Wednesday, December 28, 2005

Fifty/Fifty

Southerly winds ahead of a developing low pressure area in the lower Ohio Valley are bringing mild conditions to most of the East Coast this afternoon. Temperatures are above freezing everywhere except northernmost New England, and the 60s are being observed as far north as northern and western West Virginia. Aided by strong upper level support (For the geeks, that means "positive vorticity advection" and a "negative tilt" to the trough axis), squall lines broke out in early afternoon from southern Ohio through Kentucky and in the western Carolinas.

By 3pm, temperatures at all reporting locations in the Washington DC metro area were in the 50s, except for the river-contaminated readings at National and Quantico. At 4pm, however, the official temperature did make it to 51. Radar is showing some showers scattered from north of Pittsburgh through West Virginia into southwest Virginia.

Tonight and Tomorrow

Latest indications are that any serious showers won't arrive in our area until around midnight tonight, ending by mid afternoon. The heaviest rain should be well to the south, through the eastern Carolinas and far southeast Virginia. There is a 70% chance of rain by morning with low temperatures from 41 to 45. Rain probabilities will decrease to 40% by early afternoon tomorrow with highs around 50.

Fifty BELOW

I've been a scifi fan ever since I discovered the Tom Swift, Jr. series not long after they were originally published. One current author who's been below my radar screen, however, is Kim Stanley Robinson, since I'm still working through the backlog of books acquired in a decade of the annual New Year's sales at the Golden Notebook. Robinson has won multiple Hugo and Nebula awards, which scifi fans will recognize as two of the most prestigious awards in the field. His book, Forty Signs of Rain, published last year, was recommended by Books from the Crypt of North Potomac in the book issue of the Bulletin of the American Meteorological Society in May. It was the first in a trilogy about the effects of climate change right here in River City.

The second book, Fifty Degrees Below, was recently published, and it was reviewed in the WaPo Style section last week. The author was interviewed by the UK Guardian back in September in connection with the publication of the latest book:
"In the wake of a tropical storm, a low-lying American city is drowning. Buildings are demolished and bridges knocked out; tens of thousands of people are without electricity or fresh water; hospitals are bursting at the seams with the sick and the dead."
The city, in this case, is not New Orleans, but Washington DC, which has been flooded at the end of the first book. The premise of the second book is a severe cooling triggered by the shutdown of the Gulf Stream. This is similar to that of "The Day After Tomorrow", but apparently much more scientifically plausible.

Tuesday, December 27, 2005

As December Goes . . .

After yesterday's official high of 48, temperatures are closer to seasonable levels for late December in the Washington DC metro area, mainly in the mid 40s under partly cloudy skies. Winds have been brisk at times, but well below yesterday's levels. Across the country, there is virtually no precipitation east of the Rockies, except for the Dakotas.

Tonight and Tomorrow

Tonight's lows will range from the mid to upper 30s. Tomorrow will see increasing cloudiness and highs around 54.

. . . So Goes January?

Someone suggested in the previous comments that this weather is so boring it should have a web site called "LowercaseWeather.com". The one thing that is constant about weather is that it will always change. Since things are a little slow now, I had the chance to do some homework.

Following on to Matt's earlier discussion, I looked at the historical relationship between December and January weather in Washington. The chart on the left is a plot of each year's December average temperature (x-axis) vs. the following January's average (y-axis). As you can see, there is a lot of scatter to the data. The solid sloping line is a regression line, which minimizes the collective distance to all of the plotted points. The algebraic equation for that line is shown in the upper part of the graph, along with R². R is known as the correlation coefficient. It is a measure of how well two sets of data are correlated (in this case, December and January temperatures). The value of R can vary all the way from -1 (perfect, but opposite, correlation) to +1 (directly correlated). A value of 0 indicates the relationship is completely random. In this case, the value of R is 0.4, since R² is 0.16. This shows that the quantities are related, but not very strongly. Without getting too technical about it, R² represents the amount of variability of one set of data (January temperature) which is "explained" by the variability in the other set of data (December temperature). In this case, a little over 16% of the variance is explained---not random, but not terribly strong, either.

In the case of snowfall, all bets are off. The chart on the right shows a plot of total snowfall for December vs. January (trace amounts were considered 0). Notice how the points are much more random than in the temperature chart. In fact, the R² value is much less than 0.01; about ¼ of 1% of the variability of January snowfall is explained by the December amount. This is shown by the regression line being almost completely flat. What relationship does exist is actually negative, indicated by the negative coefficient of x in the regression equation. So, there is a non-zero probability that January snowfall will be low when December's is high, but the statistical reliability of that connection is extremely low.

Friday, November 11, 2005

Science and Service

FREEZE WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 6 AM EST SATURDAY
The coldest temperatures of the season in the Washington metro area rebounded to 50 or above by noon today; mid-50s were widespread by mid afternoon. This will be the first day in almost 2 weeks with below-normal temperature. The official low this morning was 38, the first time it's been below 40 this fall. Here in Montgomery County outside the Beltway, it was 35 with some frost. Dulles briefly broke the freezing mark at 31. Winds have dropped dramatically; note the much wider distance between isobars on this afternoon's weather map.

With clear skies and calm winds, temperatures tonight will drop a little further, to the upper 30s in the city and the lower 30s in the suburbs with widespread frost. Tomorrow will see a warmup to around 61 under sunny skies.

Seventh Service Salute

On this Veterans Day, Camden has included in his post below a review of the importance of weather in war. As a proud veteran of the NOAA Commissioned Corps and member of the 28th Basic Officer Training Course, I salute the men and women of this elite organization. One of the 7 uniformed services of the U.S., the NOAA Corps is one of only 2 civilian services, the other one being the much better known Public Health Service. The NOAA Corps is by far the smallest service at a total strength of about 300. Members of the Corps steer the ships and pilot the planes which support NOAA's meteorological, oceanographic, and fisheries missions.

The ancestry of the NOAA Corps can be traced back to 1807, when scientist-president (Now there's a concept!) Thomas Jefferson was instrumental in creating a "Survey of the Coast". This Coast Survey, which was responsible for developing nautical navigation charts, evolved into the Coast & Geodetic Survey (C&GS), which also had the responsibility for establishing the national geodetic network as a reference for land surveys. Civilian members of the Coast Survey served in many theaters of the Civil War, often performing mapping duty in or ahead of the front lines. The commissioned corps of the C&GS was formed when the U.S. entered World War I in 1917, in order to facilitate coordination of its activities with the military services. Over half of the commissioned officers served active duty with the Army, Navy, or Marines during both WWI and WWII. Following a series of reorganizations of scientific agencies, the NOAA Corps as it exists today was formed along with NOAA in 1970.

Among the many duties of NOAA Corps officers is piloting hurricane reconnaissance missions. Military Officer magazine had an article in 2003 about one such flight. Surveying the land, air, and oceans and performing scientific research on the environment, the NOAA Corps shows that is possible to promote public safety without using weapons of destruction.

College students who meet the eligibility requirements, like to work outdoors, want to serve the country without blowing things up, and are interested in qualifying for full Veterans Administration benefits (Yes, the GI Bill paid the rent for grad school.), should check out the application process.

Armistice Day Storm

Paul Kocin has a review of the Armistice Day Storm of 1940 in the Weather Channel blog. This is the same storm which earlier led to the collapse of the Tacoma Narrows Bridge.

Monday, November 7, 2005

Bridging the Seasons

Yesterday's high of 77 in Baltimore tied the record set in 1978, and the high of 77 also in Washington was only 1 degree short of the record set in 1948. It was a perfect day for 13,000 people to attend a simulcast of Porgy and Bess on the Mall.

As Jason said earlier, the air behind the cold front which passed through the Washington metro area last evening is still above normal for this time of year. Temperatures by mid afternoon today were in the mid to upper 60s, compared with a normal high for the date of 60. Nov. 6 (yesterday) is also the earliest date in the fall which has never reached 80. The low has failed to break 40 officially yet this season, although the normal low is now 42. In fact, every date in November has a record low below 30 degrees. Total heating degree days through yesterday were 50% below normal for the month and 27% below normal so far this season.

The tropics remain quiet.

Tonight and Tomorrow

Tonight will be mostly clear, lows in the upper 40s city, low 40s 'burbs. Tomorrow will be partly cloudy with clouds increasing late in the day and highs near 70.

Eye in the Sky

The WaPo reports today that Bethesda-based Lockheed Martin is one of 3 companies each receiving a $10 million 6-month contract for the definition and risk reduction phase of development for the next generation of operational weather satellites, GOES-R. The new series of satellites is scheduled for launch in 2012. It will have significantly faster imaging and higher spatial resolution than current satellites.

A Troubled Bridge

The current issue of Weatherwise Magazine, which also has a redesigned web site, notes that today is the anniversary of the collapse of the Tacoma Narrows Bridge on Puget Sound in 1940. The bridge, which began oscillating as soon as it opened on July 1, eventually collapsed spectacularly 4 months later. Although wind caused the fatal oscillation, it was only in the range of 30-40 mph ahead of a Pacific storm entering the Northwest. The lessons learned from the bridge disaster have contributed to much safer designs for today's suspension bridges. PBS NOVA has a video of the bridge on their web site.

Friday, November 4, 2005

Signs of the Seasons

(After Verizon dug a five-foot-deep trench in my front yard attempting a repair to the 37-year-old string connecting to my tin-can modem, I wasn't sure there would be an afternoon update, but here it is. If any of you argued for underground utilities after the damage from Isabel, I can testify from long experience: You don't want to go there!)

High, thin clouds are retarding the temperature rise this afternoon in the Washington metro area, but the 5-month stretch of warm temperatures is continuing into the new month of November. Since June, which had 17 days above the long-term average, the number of days at or above normal has been: July: 23, August: 25, September: 27, October: 21. Most reporting locations have reached 70 or above, although the Anomalous Airport has reported only 66. Mild and dry conditions are on tap through the weekend; all of the models are predicting only single-digit "POPs" (probabilities of precipitation) through Sunday. This is a good thing, since getting Verizon's exposed string wet would certainly jeopardize Monday afternoon's update.

Tonight and Tomorrow

Tonight's lows will be in the mid 50s downtown to around 50 in the suburbs. Tomorrow should be mostly sunny with highs in the low 70s, mid 70s if we get more sun.

Seasonal Shopping

In a sure sign that fall is deer mating season, the WaPo reports that a deer was shot to death yesterday in a Germantown Giant after apparently being disappointed by a leftover Halloween display and attacking the pharmacy. (There was no word on whether the animal was upset on finding out that the boxed milk is not on the dairy aisle, or with boxed juice, or with coffee and tea, or with baby products, but is in fact on the baking products aisle.)

Another sign of the season is the arrival through the mail slot yesterday of my favorite weather catalog, Wind and Weather, from northern California. Over the years, they have expanded from barometers, weathervanes, and sundials to all manner of indoor and outdoor tchotchkes, but they still have a nice selection of weather instruments.

Casio has apparently given up on their barometer watch, but the GQ (Geek Quotient) of this year's wrist adornment is unsurpassed: The "Multi-purpose Weather Watch" measures "wind speed (0 to 186 mph) with a Swiss-made flip-up impeller." This is on top of air pressure (down to 8.84"!), temperature (-40F to 176F), wind chill, stopwatch, and date/time alarm. This sounds like great fun and just the thing to have if you're planning to fall out of an airplane at about 50,000 feet or to spend some time in the toaster oven on defrost setting. On the other hand, I'm not sure I want to wear a device which requires me to go sideways through doorways. Only 51 shopping days left to the holidays!

Thursday, November 3, 2005

Fabulous Fall, Failing Forty, Finding Fault, Fixing Funding

There's not much to say about such fine November weather except, "Look for more and better tomorrow." If you are reading tomorrow's afternoon update from work, it won't be because we didn't warn you! Start thinking up your excuses now for leaving early. Temperatures which just nudged or slightly exceeded 70 today will make a more emphatic push into the 70s tomorrow. As Josh noted in the previous comments, the Official Observation still has not reached 40 degrees this season, although some places have seen readings in the 30s.

Tonight and Tomorrow

Tonight's lows will range from the mid 40s in town to near 40 in outlying areas. Tomorrow's sunny skies will drive temperatures to the low 70s, possibly mid 70s in the warmer locations.

More Hurricane Fallout

It's clear that the implications of this year's record hurricane season will play a major role in the public policy debate for a long time. Today's WaPo has an article, "Levees' Construction Faulted In New Orleans Flood Inquiry", which describes the preliminary findings of some expert studies indicating that design or construction failures led to the flooding from Katrina.

NOAA Administrator Conrad C. Lautenbacher has recently responded to the criticism of NOAA and the National Weather Service which was made in a series of Miami Herald articles. Dan discussed this issue (under the heading "A Scathing Review") here a couple of weeks ago.

On the other hand, the Herald reported on Sunday that $25 million has been proposed for improvement in hurricane forecasting.
"Included in the request are new equipment for hurricane hunter planes, more buoys to track ocean conditions, a redesign of the sensors dropped into storms, repairs to damaged equipment, and most notably, another hurricane hunter plane."
While this request deals with equipment, meteorologists say more is needed in the form of:
"more flight crews and flight hours for hurricane hunter planes, more Hurricane Center forecasters, more scientists to build a new hurricane computer model, and equipment and staff members for NOAA's Hurricane Research Division in Miami, whose base budget hasn't topped $3.5 million in more than two decades."
Can you believe NOAA is spending only $3.5 million per year on hurricane research? Every time something like this comes along, it reminds me why I left the government after only 5 years of civilian employment, even though I would be getting a very nice pension by now if I had stayed.

Wednesday, November 2, 2005

Afternoon Update

This afternoon's weather map shows a large high pressure area dominating most of the U.S. There is virtually no precipitation anywhere east of the Rockies except for some showers in the Upper Peninsula of Michigan and northernmost Minnesota.
image
The rain associated with the cold front which we discussed yesterday did bring the lightest of accumulations to the western and northern fringes of the Washington metro area. Potomac Falls HS in Sterling, VA, for instance, managed to eke out 0.01".

Temperatures this afternoon are seasonable; they range from 60 through the low 60s.

Regional radar image at 10:09pm last night from the Weather Channel.

Tonight and Tomorrow

Tonight, clear skies and light winds will promote cooling to the mid 40s in the city, as low as the mid 30s in some outlying areas. Tomorrow will be sunny and a little warmer, highs in the upper 60s.

Tropical Beat

"There are no tropical cyclones in the Atlantic at this time," and none are expected to develop through tomorrow.

Broadcast News: Global Warming Special

Reminder: The PBS global warming special is on tonight at 8pm (both channels 22 and 26 locally). South Carolina ETV, which co-produced the show, has a preview on their web site.

Disaster Recovery

WaPo prints an AP story today reporting that Donald Powell, the chairman of the Federal Deposit Insurance Corporation, has been appointed to "oversee federal efforts to rebuild the U.S. Gulf Coast region devastated by hurricanes Katrina and Rita." Among Mr. Powell's many qualifications for overseeing disaster recovery are:
  • Downsizing the FDIC
  • Running the First National Bank of Amarillo, Texas
  • Raising over $100K for the Bush campaign
COMET: The Little Web Schoolhouse

One of our objectives here at CapitalWeather is to educate as well as entertain. The National Center for Atmospheric Research (NCAR) has developed an online educational program called COMET (Cooperative Program for Operational Meteorology). Modules are available for a variety of levels, from kids through operational forecasters. One of the more intriguing hurricane topics is "Community Hurricane Preparedness", in which "the last section is a decision-making exercise in which you, as the emergency manager, must decide when and if to call for an evacuation as a hurricane moves toward your city." Presumably, if you make the right decision, it says, "You're doing a heckuva job."

Tuesday, November 1, 2005

Nice November Start

High, thin clouds ahead of a weak cold front are keeping November 1 from being quite as spectacular as Halloween, but it's a nice start to the new month. Temperatures around the Washington DC metro area are in the range of upper 60s to 70. Showers associated with the front, a few of them moderate, were making their way at mid afternoon from just past Pittsburgh to Morgantown, WV and across western West Virginia.

Regional radar image at 3:53pm from The Weather Channel.
image
Today's forecast problem is not earth-shattering, but it does illustrate one of the classic dilemmas in forecasting for the Nation's Capital: Will it rain tonight as the cold front moves through? On the one hand, the models are remarkably low in their "POPs" (probabilities of precipitation). One of them, the "NAM", keeps the POP no higher than 8% through tomorrow morning. The latest model run, from data collected at 1pm this afternoon, brings light precipitation (up to 0.10") about halfway across Maryland before drying it out. The National Weather Service forecast discussion this afternoon says, "The models have been pretty consistent bringing this boundary through with very little measurable precip and rapid drying behind the boundary." On the other hand, there is the "look out the window" (or at least the Doppler radar screen) factor. The line of showers is quite respectable-looking, and it has already brought about 0.1" to Pittsburgh. There is, however, the matter of those pesky mountains between there and here which often break up the precipitation before it can reach the metro region.

My bottom line is: The long-term average number of days with measurable precipitation in November is the third lowest of the year at 8.5, but this is still 28%. The current situation is at least as likely as any random November day to produce precipitation. Therefore, I would have to say that the probability of precipitation is 30% tonight, rather than ruling it out, as the official forecast does. The caveats are: Any rainfall will be very light and scattered, and it is more likely to the north and west of the immediate metro area.

Tonight and Tomorrow

Tonight will be mostly cloudy with a 30% chance of light and scattered showers, lows near 49. Tomorrow will be sunny and a little cooler with highs in the mid 60s.

Tropical Beat

The tropics remain relatively quiet. There are several tropical waves across the Caribbean and Atlantic, but none of them are showing signs of development.

Broadcast News

I accidentally came across some nice hurricane video on NASA TV this morning, but it's not listed in the schedule. If you're flipping channels, you might want to look for it (channel 21 on Comcast Montgomery analog).

The NASA hurricane web page has an animated depiction of the 2005 hurricane season from Arlene through Wilma, including sea surface temperatures, clouds, and storm tracks. I didn't have time for the 2-hour download, so if anyone looks at it, please let us know in the comments how it looks.

WETA, channel 26, is broadcasting "Global Warming: The Signs and the Science" tomorrow night at 8:00. The show is hosted by Alanis Morissette; it "profiles people who are living with the grave consequences of a changing climate, as well as the individuals, communities and scientists inventing new approaches." A 2-minute preview is available to download.

Cinemania

The Weather Man movie got 2 Thumbs Up® from Ebert and Roeper last weekend. As Jason pointed out in his review below, it's not about meteorology; the science is somewhere between negligible and nonexistent.

Monday, October 31, 2005

Bootiful, Spooktacular Weather: Monstrously Mild

It isn't enough to threaten the Washington Halloween record of 85 set in 1950, but today's warmth is much more in line with the highs of 70 and 79 of the last two Halloweens than the nasty 47 of 2002. Despite the Frost Advisory, the low last night at Afternoon Blog Central here in Montgomery County didn't even break 40; the official low was 42. There is not a cloud in the sky for hundreds of miles around as temperatures climbed into the low 70s this afternoon.

Tonight and Tomorrow

With the very low humidity, temperatures will drop quickly after dark, but they will still be mild for the season, mainly in the 50s at Trick-or-Treat time. Lows in the early morning should be in the low 40s in the suburbs to upper 40s downtown. Tomorrow will again be sunny and mild, highs in the low 70s.

Tropical Beat

The tropics are calming down following the dissipation of Beta yesterday over Nicaragua. The last advisory was issued at 10pm last night.

There is a tropical wave in the eastern Caribbean which is not showing signs of development.

Broadcast News

Bird watchers, who are at least as obsessive-compulsive as weather nerds, got a dividend from the recent hurricanes when sea birds were blown hundreds of miles away from their usual habitats. NPR had an interview yesterday with the president of the South Alabama Birding Association on the subject.

Energy Watch

CNBC reported this morning that natural gas prices were dropping this morning by as much as 6% to a 6-week low, although they are still nearly double the levels of last year. We are finishing this month with about 10% fewer heating degree days than normal in the Washington area. We'll have more on this as the heating season develops.

Friday, October 28, 2005

Taking a Beta-ing

FROST ADVISORY IN EFFECT FROM 4 AM TO 8 AM EDT SATURDAY

Rain from a weak low pressure area off the North Carolina coast is remaining well offshore, and the Washington DC metro area is enjoying a mostly sunny late October afternoon, with temperatures in the mid 50s.

Tonight and Tomorrow

Clear skies and low winds tonight will allow temperatures to drop into the 30s in many locations, and there is a frost advisory in effect for the entire area, including the District itself. Tomorrow will feature sunny skies and highs around 56. The weekend, especially Sunday afternoon, looks like a fine time to get in that one last lawn mowing of the season.

Tropical Beat

Tropical Storm Beta continues to move slowly off the Nicaragua coast. The Miami Herald and Washington Post (Reuters) reported that the Colombian-owned islands of San Andrés and Providencia were being lashed by the storm. Its 65 mph winds at 5pm are expected to intensify to hurricane strength, possibly by tomorrow. If it does become the 13th hurricane of the season, it will beat the old record of 12. The forecast track along the Nicaragua/Honduras border puts it close to the region which was devastated by the flooding from infamous Hurricane Mitch in late October 1998. The toll from Mitch was the deadliest in the Atlantic Basin since 1780. Some unofficial rainfall reports from that storm were over 48 inches at the higher elevations.

A tropical wave in the central Caribbean is showing no signs of development, and its area of showers may be absorbed into Beta.

Climate Clues

An article about Arctic warming which was published online September 22 has appeared in the issue of Science magazine published today. The article, entitled "Role of Land-Surface Changes in Arctic Summer Warming", analyzes feedback effects from atmospheric warming. It finds that local warming caused by decreased albedo (reflectivity) from earlier snow melting is on the order of 3 watts per square meter per decade, which is comparable to the heating from a doubling of atmospheric CO2 alone. An accompanying analysis, "Tipping Points in the Tundra", says, "Environmental changes in the Arctic may be an early warning system for global climate change, and recent reports from the region are alarming."

Weather Man Movie

I agree with Jason that the "Weather Man" movie sounds like a mixed bag. I'm waiting to hear from Ebert and Roper (set your TiVo for 1:05am Sunday) to form my final opinion on whether it's worth seeing. If you do decide to go, showtimes and online ticket ordering are available at Moviefone.

Wednesday, October 26, 2005

Becoming Better and Beta

FROST ADVISORY IN EFFECT FROM 2 AM TO 8 AM EDT

Today's weather map shows a large high pressure area centered over Ontario and a deep low pressure area (yesterday's nor'easter) centered over the Maritime provinces of Canada. The pressure gradient force between these two features, modified by the Coriolis force, is producing a geostrophic wind in the form of strong northwesterly breezes over the Northeast and Mid Atlantic states. Here in the Washington metro area, winds have been gusting as high as 26 mph, keeping temperatures in the mid 50s despite abundant October sunshine. Overall, it's a much better day than yesterday.

Chart by CapitalWeather.com from NWS dataimage
Yesterday's 0.59" of rain in the Official Bucket puts the new record for October precipitation at 9.41", vs. the previous record of 8.81" in 1937. This month is now tied for 22nd wettest overall in 135 years of record in Washington.


Tonight and Tomorrow

Tonight, diminishing winds and clear skies will help temperatures dip to the coldest levels so far this season: near 41 inside the Beltway, as low as the mid 30s in the outer suburbs. There is a frost advisory in effect for the western and northern suburbs. Temperatures will have a hard time rebounding tomorrow as clouds increase and highs remain in the mid 50s.

Beta on Deck

That low pressure area in the southwest Caribbean is showing more signs of becoming Beta. The afternoon tropical weather discussion from NHC points out the "hallmarks of development": dropping pressure, curved convection bands on satellite becoming better defined. It's most likely an artifact, but the latest image I'm viewing as I write this shows an eye-like feature; it's just northwest of the label for longitude 80W.

Media Mutters

Once again, the WaPo trashes science for the sake of generating "news". It took 2 "Staff Writers" to find enough morons to produce a story on how some Florida residents were "surprised" by the strength of Wilma, particularly on the east coast. Even the mayor of Fort Lauderdale is quoted as saying he expected a Category 1 storm. Excuse me, but what part of Category 2 don't you understand? Even if there were any reputable forecasts of Category 1, which I most seriously doubt, the fundamental rule of preparedness is to anticipate one category higher than forecast. In any case, a number of people (I believe 6) died as a result of ignoring the risk of Katrina when it was a Category 1 in the Miami-Dade area. Rather than pointing out the outstanding accuracy of the forecast track even before the turn away from Yucatan, the article digs up a bureaucrat from Silver Spring HQ to mumble about the difficulty of forecasting intensity.

Broadcast News

The dcrtv blog reports the latest chapter in the misadventures of former Channel 9 weatherman and now inmate Bill Kamal. When Kamal's former station in Miami was knocked off the air by Wilma, someone put on an old hurricane preparedness tape by Kamal. The tape ran for about 10 minutes before the mistake was noticed and it was taken off.

Tuesday, October 25, 2005

Record Rainfall; Beta Testing

Temperatures this afternoon in the Washington DC metro area are more typical of an average day in mid or late December. Mid or even low 40s prevail as some scattered showers linger in the area. In the higher elevations, snow has been falling, with as much as 6" reported this morning in western Maryland and West Virginia.

Yesterday's rainfall of 0.57" was enough by 0.01" to set a new record for maximum October monthly rainfall in Washington. This record is especially significant since last month set the record for minimum September precipitation. With additional rainfall around an inch today, this month has achieved the dubious distinction of being 1 of only 25 months overall in 135 years to have exceeded 9", and it is well on the way to reaching 10".

Tonight and Tomorrow

Cloudy skies will continue tonight with lows near 40 and a 30% chance of showers (or snow flurries in the colder locations). Tomorrow will see gradual clearing and highs in the mid 50s. A frost advisory may be needed tomorrow night.

Tropical Beat
image
The idea of Wilma merging with a non-tropical low to produce a "perfect storm" turned out to be a little simplistic. The image shows the surface weather map early this afternoon (18Z or 2pm EDT) from the National Weather Service HPC. The center of Wilma is shown as the small hurricane symbol in the warm-air sector to the northeast of the large nor'easter pummeling New England. (Providence RI was reporting wind gusts of 41 mph, for example, at 4pm.) Although the non-tropical low is absorbing some of the moisture and energy of the tropical system, Wilma is an intense enough storm to maintain its own identity within the larger circulation. At 5pm, the 105 mph winds of this morning had decreased to 85, the storm was losing its tropical characteristics, and advisories were discontinued.

With Wilma rapidly exiting stage right, the search is on for storm Beta. A suitable candidate has appeared in the form of a low pressure area located in the southwestern Caribbean (11N 78W, for those of you keeping score at home). The National Hurricane Center reports this afternoon that computer models "unanimously" agree this area is stocked with those essential ingredients for Momma Nature's favorite Weather Grill tropical treats: warm salt water and low-fat wind shear.

Stupid Storm Stunts

For more on Al Roker's excellent adventure and other stupid storm reporting tricks, check out the reruns of last night's Daily Show on Comedy Central. Since ridicule doesn't reduce this foolish behavior, it seems that a reporter or crew member will have to be killed or maimed before the various news media reform their storm reporting techniques.

Monday, October 24, 2005

Wilma's Wrath Wanes, Waxes

This afternoon's weather map shows Hurricane Wilma emerging as a rejuvenated Category 3 storm over the Atlantic after crossing southern Florida this morning. As the storm continues to accelerate to the northeast, it will interact with a non-tropical frontal system associated with a low developing near Cape Hatteras.

At mid afternoon, radar showed the northern edge of the rain shield from this system extending from near Richmond northeastward across the mouth of the Potomac, the middle of the Chesapeake Bay, central Delaware, and near Atlantic City, NJ. Further west, rain and showers extended from western Pennsylvania through central West Virginia to the border of Virginia. The mountainous portion of this area appeared to include sleet and snow. In fact, Hot Springs, VA reported snow with visibility less than 1/4 mile at 3 and 4pm. At 5pm, showers were approaching the Beltway from the south.

Temperatures around the Washington metro area were mainly in the upper 50s with a northeast wind gusting as high as 28 mph.

Image of NWS/NCEP 24-hour surface map and 6-hr precipitation forecast valid 18Z (2pm EDT) Tuesday

By early afternoon tomorrow, the remains of Wilma and Tropical Depression Alpha will have merged with the "extratropical" low to "bomb out" just south of Long Island. Note that the light blue areas in the image represent precipitation as high as 1.25" in 6 hours. The area within the dashed blue line including West Virginia, western Maryland, and the mountains of Virginia is cold enough for snow showers.

Tonight and Tomorrow

Tonight, rain will continue to advance from the southeast. Heaviest amounts will be on the Eastern Shore and in southeastern Virginia. Low temperatures will drop to the mid 40s. The chance of rain diminishes to 30% by late afternoon tomorrow with highs around 50.

Tropical Beat

Wilma made landfall this morning on the west coast of Florida south of Naples as a Category 3 storm. This is the first time that more than 3 hurricanes have made landfall in the U.S. at Category 3 or higher in the same year. It was downgraded to Category 2 while over southern Florida, but was upgraded again to Category 3 after crossing the east coast into the Atlantic. By 5pm, it was back up to 120 mph peak winds as it moved northeast at about 37 mph.

After a brief fling as a Tropical Storm over the weekend, Alpha became Tropically Depressed following its crossing of Hispaniola. It had maximum sustained winds of 35 mph this morning, but it is expected to be absorbed into the circulation of Wilma.

There are several tropical waves scattered across the Atlantic from near Africa to Central America.

Faces Behind the Signatures

If you read the advisories and discussions issued by the National Hurricane Center, you may have noticed that each one is signed with the name of the lead forecaster. The Daytona Beach News-Journal last fall published a set of profiles of the faces behind those signatures.

Hurricane Seminar Reminder

The AMS Environmental Science Seminar on hurricanes is tomorrow. Scroll on down to Friday's afternoon update for details.

Friday, October 21, 2005

Waiting, Watching Wilma

After some morning showers and thunderstorms, a northeast wind, heavy clouds, and a light drizzle are keeping temperatures in the Washington DC metro area in the distinctly non-Octoberish low 50s. (The long term average high for today is 66.) The precipitation is associated with a low pressure area moving slowly eastward through the Ohio Valley and a wave on the front extending eastward from the low to the southeastern Virginia coast. Rainfall amounts in the area have been quite light; the official amount so far is only 0.01", while heavier showers at Dulles produced only 0.12".

Tonight and Tomorrow

More rain is likely (90% chance) tonight with lows within 2 or 3 degrees of the current 52. Chances of rain will decrease to near 50% by late in the day tomorrow, but skies will remain cloudy with highs near 60.

Tropical Beat

Hurricane Wilma continues to pound the Cozumel/Cancun area of the Yucatan peninsula. Early this afternoon, the center of the storm was just 15 miles offshore from Cozumel; maximum winds were 140 mph. By late afternoon, the eye was crossing Cozumel, and the edge of the eyewall was on the coast of the peninsula. The track is still to the northwest at 5 mph, but a turn to the northeast is still expected over the weekend. Fortunately for southern Florida, an extended visit to the Yucatan will weaken the storm. Increasing wind shear over the Gulf of Mexico is another likely cause of weakening. If Wilma does make landfall in Florida as a Category 3 or higher, this would be the first time that 4 major hurricanes have made landfall in the U.S. in the same year.

Meanwhile, a tropical wave in the eastern Caribbean is showing signs on satellite imagery of developing a circulation. It could become Tropically Depressed in the next few days. If it turns into a named storm, it would be the record-setting 22nd storm of the season named "Alpha."

Capitol Climate: All-Star Cast!
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Clear your calendar for next Tuesday early afternoon. The American Meteorological Society's Environmental Science Seminar Series is presenting a panel discussion on the subject, "Hurricanes: Are They Changing and Are We Adequately Prepared for the Future?"
  • Time: Tuesday, October 25, 2005, 12:00 - 2:00 p.m. (Followed by a Reception! Note to starving interns: This sounds like free food.)
  • Location: Dirksen Senate Office Building, Room G-50
The speakers have all published important papers in the last several months on trends in hurricane occurrence and intensity, some of which you may have read about right here on CapitalWeather.com:
  • Dr. Kevin Trenberth, Head of the Climate Analysis Section, National Center for Atmospheric Research (NCAR), Boulder, CO
  • Dr. Judith Curry, Professor and Chair of the School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA
  • Dr. Kerry Emanuel, Professor of Atmospheric Science, Massachusetts
    Institute of Technology, Cambridge, MA
The questions to be discussed are:
Are hurricanes, or certain categories of hurricanes, changing? Are these changes more likely tied to a globally-averaged climate warming or are they more likely to be manifestations of natural climate variability? Can large storms be unaffected by a globally-averaged climate warming that has resulted, in part, in an altered hydrologic cycle (i.e., more water vapor in the atmosphere)? Is it reasonable to presume that natural cycles and oscillations can go unaffected by a globally-averaged climate warming? Are there limits on a hurricane's intensity and, if so, what are they? Is there any scientific basis for concern over the plausibility of hurricanes in excess of a category 5 hurricane in the foreseeable future, in a climatically-altered world?
The public is cordially invited.

Katrina Post Mortem

Today's WaPo reports that a FEMA aide testified in hearings that FEMA Administrator Mike Brown's assistant was notified at 11am on Aug. 29 that the New Orleans levees had been breached. These warnings were ignored for 16 hours. If you were reading CapitalWeather.com that day, you saw quotes from the Times-Picayune storm blog as early as 10:30 which indicated flooding was occurring.

Thursday, October 20, 2005

Wilma Wending Westerly Way

A cold front which passed through the Washington DC metro area overnight is becoming stationary across southern Virginia. Temperatures which had been in the low 60s earlier have dropped to the upper 50s with some light showers. Radar in early afternoon showed an area of showers from near Morgantown, West Virginia eastward across far western Maryland, the eastern panhandle of West Virginia, and extreme northwestern Virginia. By mid afternoon, the bulk of the rain had moved quickly to north-central Maryland and the Baltimore area, but a few showers reached the western suburbs of Washington.

Tonight and Tomorrow

Tonight will be cloudy with a 50% chance of showers and lows in the low 50s. Tomorrow, cloudy skies and an east wind will keep high temperatures in the mid 50s with a 70% chance of rain.

Tropical Beat

Accuweather image via CNN.com.
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Although it weakened somewhat yesterday from its most extreme intensity, Hurricane Wilma is still a Category 4 storm with maximum winds of 145 mph as of 2pm and back up to 150 at 5pm. It has been moving more westerly than originally expected, and so it is likely to make landfall on the northeastern Yucatan peninsula or remain just offshore tomorrow before turning toward the northeast and heading for southwestern Florida. The storm was centered 135 miles southeast of Cozumel in late afternoon, moving northwest at only 6 mph. Reports from Cozumel showed winds from the east-northeast at 35-40 kt this afternoon. (You can track real-time conditions at the Aviation Digital Data Service METAR web page. Enter station code MMCZ for Cozumel or MMUN for Cancun, although the latest from Cozumel states "FUSE POR WILMA".)

The track models are fairly consistent in turning Wilma toward the northeast and across Florida, but a few are hinting at a later threat to the New England coast, or even Cape Hatteras and Ocean City. The official "zone of uncertainty" extends as far west as the Chesapeake Bay and the lower Potomac. (There is probably a more descriptive term for the shape, but we'll leave that to Wonkette).

You Don't Need a Weatherman
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Watch out, Topper, Bob, Sue, Joe, and company: A press release from Televirtual's UK Media Lab announces the world's first artificial TV personality. (That point might actually be debatable.) METman is "a virtual weather reporter/forecaster, whose entire performance is generated automatically from a few lines of text-based data issued as a meteorological summary, and accompanied by a weather map update." The METvoice speech engine is driven by XML-style mark up language to control lip-synch, moods, and gestures.

Wednesday, October 19, 2005

Wobbling Wilma Weakens

South to southwesterly breezes ahead of a cold front are pushing temperatures in the Washington DC metro area again into the upper 70s this afternoon. There is virtually no precipitation anywhere in the U.S. east of the Rockies.

Tonight and Tomorrow

Temperatures tonight will drop into the low 50s. Tomorrow will feature considerable clouds and cooler temperatures with highs around 64.

Tropical Beat

Hurricane Wilma intensified at an astonishing rate overnight, reaching the Atlantic Basin record low barometric pressure of 882 mb/26.05 inches this morning. (The previous record was 888 in '88 with Gilbert.) The storm weakened slightly during the day; the pressure rose to 900 mb at 2pm, and the maximum winds were "only" 165 mph, down from 175. At 5pm, max winds were 160 mph, and pressure was 892 mb. The path was wobbling (Can you say "trochoidal", boys and girls?) around an average direction of west-northwest at 7 mph.

Conditions will be somewhat less favorable once Wilma enters the Gulf of Mexico, but it is still likely to be quite strong if it approaches Florida as expected towards the weekend. All interests in the Florida Keys and peninsula need to keep an eye on developments. Some models are suggesting the hurricane will link up with a low pressure trough now moving eastward through the U.S. This could threaten parts of the East Coast, particularly southeastern New England. On the other hand, a close encounter with the Yucatan could throw a monkey wrench into the whole scenario.

Climate Mash
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Just in time for Halloween is the Climate Mash, a fun video from the Clear the Air organization.

Broadcast News

The PBS NewsHour had a discussion about hurricane activity last night with Christopher Landsea, a meteorologist with the hurricane research division at NOAA, and Judith Curry, a climate scientist and chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology.

Tuesday, October 18, 2005

Weekend Wilma Worries?

Temperatures this afternoon are about 10 degrees warmer than yesterday in the Washington DC metro area, ranging from 77 to as high as 81 in the southern portions of the region. The only precipitation east of the Mississippi consists of some scattered showers in northern New York and New England.

Tonight and Tomorrow

Under clear skies, temperatures tonight will drop to the low 50s in the city and the mid to upper 40s outside the Beltway. Tomorrow will once again be sunny and dry with highs near 76.

Tropical Beat

Wilma became a hurricane this morning; at 5pm, maximum winds were 80 mph and the storm was moving west-northwest at about 8 mph from a position about 180 miles south of Grand Cayman Island in the Caribbean. Wilma is expected to intensify to major hurricane status (Category 3) as it moves more toward the northwest and into the Gulf of Mexico, eventually turning northeastward toward southern Florida. The storm's impact on our area is very uncertain at this point; that depends on whether it is (1) picked up by a trough in the westerlies and moves up the Atlantic Coast or is (2) pushed offshore to the south.

Climate Clues: A Hard Rain

Image from Meehl et al., Geophysical Research Letters, Vol. 32, L18719.

Today's WaPo has an article describing a study being published online in the Proceedings of the National Academy of Sciences. The study used a climate model to investigate the effects of a doubling of CO2 in the atmosphere by the end of the century. The model predicted that there would be a large increase in the number of extreme heat events and also an increase in the intensity of precipitation. An article in Scientific American online explains that this model increases accuracy from older models by doubling the horizontal resolution from a distance of 50 km between gridpoints to 25 km. By way of comparison, this is almost 16 times the resolution in each horizontal direction compared to what was used routinely in daily weather forecasting just a couple of decades ago.

This study is consistent with one recently reported by NCAR, the National Center for Atmospheric Research, and published in Geophysical Research Letters, which found that precipitation would become more intense with an increase in CO2. The biggest increases would be over land in the tropics. Other areas with large increases include northwestern and northeastern North America.

Monday, October 17, 2005

Warming Washington, Wandering Wilma

After yesterday's high of 68 and a low this morning of 53, temperatures this afternoon in the Washington DC metro area are well into the upper 60s under bright sunny skies. This is likely to be the 15th day so far this month with temperatures at or above normal. The first half of the month has averaged almost 5 degrees above the long-term normal. I turned on my heat for the first time last night, probably the latest I've ever done so as a homeowner.

Tonight and Tomorrow

With diminishing winds and clear skies tonight, lows should be in the low 50s inside the Beltway and in the 40s in the outlying areas. Tomorrow will again be sunny and dry with highs around 75.

Tropical Beat

At 5am this morning, TD 24 became Tropical Storm Wilma. This is only the second time in over 150 years that 21 storms of tropical storm strength or higher have occurred in a single season. Wilma is only 2 days short of beating by a month the development of the previous 21st storm on Nov. 15, 1933. Wilma has also already exceeded the strength of that 1933 storm, which only reached minimal tropical storm strength of 35 kt (40 mph). At 2pm, maximum sustained winds were 50 mph; strengthening to a hurricane is expected. The storm has drifted southward recently, but a more westerly and eventually northwesterly track is expected. There is huge uncertainty in the path at this point, however.

Media Matters

The Weather Channel has begun running ads for the Weather Man movie starring Nicolas Cage as a Chicago TV weatherman whose "personal life is in complete disarray." The movie opens next Friday.

Tony Perkins will appear exclusively on Fox 5 when he returns to Washington, not on other Fox outlets as well, according to the dcrtv blog.

Also from dcrtv is the news that Comcast in the Baltimore area will be carrying the Channel 11 (WBAL) digital weather channel "11 Insta-Weather Plus".

Friday, October 14, 2005

Nowhere to Go But Up

It's not as nasty as yesterday's heavy drizzle, but this afternoon's weather in the Washington DC metro area is still a lot like the Other Washington. Occasional breaks in the clouds have allowed some warming to push temperatures into the upper 60s to 70 range with even some low 70s in the southern parts of the region. Intermittent light rain ended at National shortly after noon, with only 0.01" recorded today. The nearest organized precipitation on radar is over northern New Jersey, Long Island, and offshore. This precipitation is circulating around a stubborn low pressure area centered east of New Jersey. Although this is a non-tropical low, it has been fed by tropical moisture, leading to flooding in large parts of the Northeast.

Tonight and Tomorrow

Clouds tonight should gradually diminish towards morning with lows near 56. Tomorrow looks like a great day to get in one more lawn mowing: mostly sunny and highs around 77.

Tropical Beat

The tropical Atlantic still has no organized activity, but it's not for lack of trying. There are tropical waves near longitudes 32W, 42W, and 58W, and there is a low pressure area near Jamaica which is being monitored for development.

Climate Clues

Speaking of the Other Washington, the RealClimate blog has links to an interesting set of articles from the Seattle Times. The paper published an extensive article on global warming on Sunday. This was followed on Wednesday by a Q and A in which climate scientists answered readers' questions. (WeatherTalk guys, are you listening?)

Geeky Weather Humor

"Question: Where did the meteorologist stop for a drink on the way home after a long day in the studio?
Answer: The nearest isobar."
"Question: What comes after 2 days of rain in Seattle?
Answer: Monday."
"Isohyet: A line of constant hotels."
"Water vapor channel: The channel that comes after MTV."

If this kind of humor appeals to you, check out meteorology's version of the Style Invitational. These are some of the entries in the Coin-A-Phenomenon #3 joke contest from the September issue of the Bulletin of the American Meteorological Society. The latest contest is looking for funny definitions of terms related to tropical storms (tropical depression, feeder bands, etc.). Entries may be submitted to letterstotheeditor at ametsoc dot org. The deadline is November 1.

Wednesday, October 12, 2005

Wet Wednesday?

4:30 update: This just in, AP reports via WaPo Tony Perkins returns from GMA to Channel 5.

Despite persistent cloudiness and a damp easterly flow, precipitation in the Washington DC metro area has been limited to some drizzle and mist this morning; only a trace of accumulation has been reported at the major observation locations. The nearest significant precipitation on radar is moving westward onto the New Jersey shore. With a little sun able to penetrate the clouds, temperatures are a degree or two warmer than yesterday, mainly in the mid 60s, although to the south Fredericksburg and Stafford were both reporting 68 by 2pm.

Tonight and Tomorrow

Under continued cloudy skies, low temperatures tonight should be near 58, highs tomorrow 67. Some drizzle or fog is possible, but there is only a 20% chance of measurable precipitation.

Where's Wilma?

The Weather Channel's Tropical Update Running Yellow Slicker Person is getting a well-earned break as "there are no tropical cyclones in the Atlantic at this time." That doesn't mean that the tropics are exactly quiet, however. The very large area of low pressure over the Caribbean and southwestern Atlantic still has stormy weather associated with it all the way from Central America across the Caribbean, the Leeward Islands, and into the Atlantic. This is bringing more heavy rain and the threat of flooding to Puerto Rico and the Virgin Islands. San Juan only had 0.50" in the 24 hours ending this morning on top of the more than 4 inches yesterday, however. There is no indication of tropical cyclone development within this area.

The Basque News and Information Channel has a report of Vince's rare landfall in Spain yesterday.

Winter Weather
Winter Outlook
NOAA has come out with the preliminary version of their winter weather outlook covering the months December through February. For those who are looking for a dramatic follow-up to at least the second most active hurricane season in over 150 years, the outlook is rather bland for much of the U.S. It calls for near-normal temperatures over the area east of the Mississippi and warmer than normal temperatures over most of the Great Plains and the Pacific Northwest. Precipitation is forecast to be near normal over nearly all of the country. Sea-surface temperatures in the central Pacific are near normal and are expected to remain that way, so neither El Niño nor La Niña events are anticipated. The outlook will be updated on Oct. 20 and Nov. 17.

Web Watch

Channel 9 has added a web page which gives nice 3-up graphics of regional temperatures, satellite, and radar. The satellite and radar images are clickable to display time loops, which are, alas, too slow for my tin-can-and-string connection. One suggestion, 9 guys: The logo probably doesn't need to obscure most of the Southern Tier and Hudson Valley of New York as well as central New England.

Tuesday, October 11, 2005

Rain, Spain, Pain, and Bane

Scattered light showers are persisting in the Washington metro area, but the rain amounts have been generally heavier to the east. This is consistent with the "NAM" model forecast (and CapitalWeather.com) yesterday, although the total amounts have been lighter overall. The Official Rain Bucket at National has recorded only a trace since noon, after 0.09" fell earlier. To the north, Baltimore reported 0.13". Annapolis, on the other hand, has had a little over a third of an inch, and the amount at Patuxent River was more than twice as much, 0.83".

Temperatures were all in the 63-64 degree range at mid afternoon with humidities around 90%.

Tonight and Tomorrow

Clouds will persist through tomorrow, with lows tonight near 56 and highs tomorrow near 64. There is a 30% chance of showers throughout the period. Amounts should be generally light, under 0.10".

Tropical Beat

Vince dissipated early this morning as a Tropical Depression on the coast of southwestern Spain. The National Hurricane Center reports that this is the first time a tropical cyclone has made landfall in Spain. Maximum sustained winds were 35 mph and the central pressure was 1002 mb.

The large area of storms in the eastern Caribbean northeastward into the Atlantic is showing no signs of organization, but it is bringing flooding rains to Puerto Rico and the Virgin Islands, where flash flood warnings are in effect. San Juan reported 4.27" in the 24 hours ending this morning, although amounts so far today have been light.

The remnants of what was once Subtropical depression 22 are also still hanging around in the Atlantic, now a couple of hundred miles east of Norfolk. No development is expected with this, either.

Gas Pains

Heating degree days (departures from normal in parentheses):
yesterday 1, month 6 (-32), season 11 (-53)

There's been a lot of attention on gasoline prices lately, but if you pay a natural gas heating bill, you're probably going to be a lot more interested in heating degree days in the coming months, even if we have a mild winter. Natural gas prices have been severely impacted by Katrita (Katrina/Rita) effects on the Gulf Coast. Although wholesale prices were down this morning about 10% from their recent high of $14.50, they are more than double what they were last year at this time. Some experts are predicting the price could go as high as $20 if there are weather-induced shortages. Since there is roughly a 10:1 ratio between this price and the price you pay Washington Gas per therm, that means that you're likely to pay at least $1.40 per therm to heat your house this winter, compared with the 75 cents you were billed last November. In fact, I see from the "Fixed Price Protection" offer I got in the mail last week from Washington Gas, the price on a 1-year contract is $1.39 per therm, and on a 2-year contract it's $1.45. Because there is a fixed-rate distribution charge built in to the bill, the increase in prices does not translate directly into an increase in the total bill, but their "Blanket Bill" offer shows a monthly amount which is a whopping 65% above the average I paid for the 12 months ending in June. (There was no decimal point in that percentage!) The rate for November's meter reading has already been posted at $1.69. In a worst-case scenario, the fixed-price offer could end up being a bargain, but if you do decide to sign up, I suggest you use a microscope to check out the terms in the 1-point type.

Frankenfish Report

The WaPo reports today that the heavy weekend rains were associated with a run of the snakehead "frankenfish" in Dogue Creek adjacent to Fort Belvoir in Virginia. At least 80 of the strange critters were caught Sunday and yesterday. They were literally jumping onto the banks as they chased minnows. It looks like fears of a massive infestation of the predatory species are being confirmed.

Monday, October 10, 2005

Hello, Columbus

FLOOD WATCH IN EFFECT FROM 2 AM EDT TUESDAY THROUGH TUESDAY AFTERNOON

Some peeks of sunshine through the clouds have pushed temperatures in the Washington DC metro area above the most pessimistic forecasts for today. At mid afternoon, temperatures were from the upper 60s to a few readings of 70. Radar shows a broken area of showers from northwest of Charlottesville south and east to near Richmond. The clouds in our area are associated with a stationary front extending from near the Outer Banks to just offshore of Cape Cod and northward to Nova Scotia. Some weak disturbances along the front are likely to produce some rain or showers as an area of spin ("vorticity") makes its way northeastward from the lower Ohio Valley. The heaviest precipitation is likely to be to the east of the metro area. However, the high amount of moisture in the air along with a source of upper-level energy and the already saturated ground combine to produce a threat of some flooding. At this point, we are less than 1.5" away from breaking the all-time October maximum precipitation record of 8.81".

Tonight and Tomorrow

Tonight will be cloudy with lows in the upper 50s and showers or occasional rain developing by morning. Rain is likely tomorrow with highs around 63. The most likely time for precipitation is from late morning through tomorrow evening.

Tropical Beat

Vince's brief reign as a hurricane has ended; peak winds this morning were down to 45 mph as the result of northwesterly shear and cool water temperatures around 22C (72F). It is now close to being Tropically Depressed at 40 mph. Vince is the earliest 20th "named" storm by 17 days. The only other one recorded since 1851 occurred on 10/26/33. That 1933 system was a tropical storm; it was followed by a minimal tropical storm (35 kt) which formed on Nov. 15 and lasted barely 48 hours.

The other areas of activity in the Atlantic are (1) an area of showers and storms from the eastern Caribbean, across the Lesser Antilles, and into the Atlantic, and (2) a tropical wave a couple of hundred miles east of the Lesser Antilles. Neither of these appear favorable for tropical development.

Columbus' Hurricanes

Columbus' first voyage to the New World was made near the peak of hurricane season, but David Ludlum, in his classic book Early American Hurricanes 1492-1870 says, "the outstanding meteorological fact of the First Voyage is simply that no hurricanes or severe storms were encountered in the West Indies despite the fact that the fleet of three small vessels traversed an area of tropical storm activity at the season of their most frequent occurrence." Was this luck, as it is sometimes described? On the 500th anniversary of the famous voyage in 1992, 2 researchers looked at the record of known tropical storms and hurricanes from 1896 through 1989 in a paper published in the Bulletin of the American Meteorological Society. They found that only 4 times in those 104 years would the center of a storm have passed within 100 km of Columbus' fleet. Only one of those storms would have been a hurricane.

Bob Sheets and Jack Williams, in their book Hurricane Watch, describe how Columbus was not so fortunate on his later voyages. On his second trip, in 1495, Columbus and his crew became the first Europeans known to have experienced a hurricane, and 2 of his 3 ships were sunk off the coast of Hispaniola. He applied that experience on his fourth and final voyage in 1502, when he noted the signs of an approaching storm. He sent a message to the governor of the new Spanish colony requesting him to hold a fleet of 30 ships in the harbor at the capital of Santo Domingo. The ships had been preparing to sail back to Spain with cargoes of gold. He also asked permission to shelter his own four ships in port. The requests were denied because of political rivalry between the governor and Columbus, and the Spanish fleet set sail right into the path of the storm. Twenty-one of the ships sank, and 500 sailors were lost. A few of the surviving ships made it back to the damaged port of Santo Domingo; only one returned safely to Spain. Meanwhile, Columbus took shelter along the south coast of the island. Three of his ships lost their anchors, but all were able to ride out the storm safely.

Friday, October 7, 2005

Super Soaker Scenario

FLOOD WATCH REMAINS IN EFFECT THROUGH SATURDAY AFTERNOON

The Washington DC metro area is being soaked with drought-busting downpours today. As of 2pm, the Official Bucket had picked up 1.23", but a mid afternoon lull was broken by a new wave of moderate to heavy rain moving up I-95. This new batch reduced visibilities as low as 1/4 mile and added 0.56" more rain by 4pm. This amount has already broken the daily record for October 7 of 1.60" in 1965. Rain is continuing, but it was light in the latest report, with another 0.24" added as of 5pm. The Doppler radar estimate of total rainfall shows some amounts in the 5" range in the higher elevations to the west.

Following the latest band of heavy showers, there will be another relative lull in the rain later this evening, but there is plenty more tropical moisture available to continue the festivities through much of the weekend. Jason has laid out a chronology of events in his earlier post. Stay tuned for updates through the weekend.

Tropical Beat

The low pressure area which was over western Cuba yesterday has weakened, but the moisture from it is moving north and bringing a lot of rain to Florida.

A low about 425 miles northeast of the Leeward Islands has been designated a "Special Feature" by the National Hurricane Center, and it has some potential to develop within the next 36 hours.

There are several tropical waves located from the central Caribbean eastward to the eastern Atlantic.

More Divine Wind

You can hear an interview with Dr. Kerry Emanuel, author of "Divine Wind", which was mentioned in yesterday's afternoon update, at the website of the Living on Earth radio program. There is also a transcript of the interview. Prof. Emanuel was interviewed on NPR on Sept. 6. The book is the text for a seminar being given this semester at UCLA. Lecture materials are being posted on the class website. If you happen to be in Bermuda next Wednesday, Prof. Emanuel is presenting a lecture at the Bermuda Biological Station for Research.

Thursday, October 6, 2005

Tammy and the Doctor

HEAVY RAIN WITH POTENTIAL FOR FLOODING THIS WEEKEND;
FLOOD WATCH IN EFFECT FROM FRIDAY MORNING THROUGH SATURDAY AFTERNOON


The National Weather Service has issued a Special Weather Statement (scroll down to 1103 am) for potential heavy rain and flooding this weekend and a Flood Watch from Friday morning through Saturday afternoon.

Parched lawns and gardens throughout the Washington DC metro area are gazing longingly southward this afternoon in hopes of receiving some rain from the remnants of former Tropical Storm Tammy. By mid afternoon, some very widely scattered showers had appeared, mainly to the west, where Leesburg was reporting heavy rain at 2pm. This was short-lived, however, as only 0.03" fell. The most intense activity was on the Eastern Shore, from the Bay Bridge southeastward to the southwestern corner of Delaware. By 3:00, many locations were reporting at least partly sunny skies and temperatures which were pushing close to or above 80; the official reading was 81 at 4pm. Dewpoints were at the "tropical" level on the muggometer, ranging from a few high 60s to the low 70s. As an upper-level trough approaches from the Midwest, the flow over our region will change from light and variable this morning to moderate (near 50 knots) from the south and southwest, helping to bring some of the much-needed tropical moisture left over from Tammy.

Tonight and Tomorrow

Tonight, the chance of rain will increase to 50% by morning as low temperatures reach only down to about 68. Rain is likely tomorrow (near 100%) with highs around 73.

Tropical Beat: Tammy

The last tropical advisory on the remnants of Tammy was issued at 11am this morning with the center of circulation over extreme southeastern Alabama. This was moving west at about 12 mph. It could even move southwest and out over the Gulf of Mexico, but regeneration is not likely. Meanwhile, the moisture originally associated with the storm is moving to the north and northeast, bringing heavy rains as far north as central North Carolina.

Further south, a weak low pressure area over western Cuba was poorly organized and unlikely to develop further, but it will bring more rain to Florida as it moves northward.

In the central Atlantic, almost 1200 miles east of the Windward Islands, a large tropical wave is being watched for potential development over the next couple of days.

Tropical Beat: The Doctor
Divine Wind
"Divine Wind", a book about "The History And Science Of Hurricanes", was delayed from its original publication date but is now available. The author is Dr. Kerry Emanuel, meteorology professor at MIT, and the book has been getting rave reviews; it is already out of stock at the publisher. Dr. Steve Lyons, the Weather Channel hurricane expert, said:
"Until I read Divine Wind I had never found a book unique enough to contain the science and the history of hurricanes accented with the prose, songs and art about them. It provides fascinating accounts of notorious hurricanes that have changed history. With sound science it educates readers about how hurricanes form, how strong they can get, how they are tracked and what types of devastation they can cause. Both meteorologist and non-meteorologist will be captivated with it. I couldn't put the book down, anxious to absorb the next fascinating piece of hurricane history. Divine Wind is a must read for everyone interested in how hurricanes work, how they have molded coastal city history and how they have affected wars.
Here are some other reviews: The book's website has links to downloadable images, supplementary material, a hurricane model computer program (Fortran 77), and other hurricane resources.

Wednesday, October 5, 2005

Tammy Tell Me True

All eyes are on minimal Tropical Storm Tammy today for the chance to bring us some drought-breaking rain. But first, let's clear up the October Urban Legend. It may be because perfect warm, dry days like today are so memorable that it seems as if October is usually a dry month. In fact, October is a transition month between the normally wetter summer and the normally drier winter. The record shows that October has only the 7th driest long-term average rainfall of all the months of the year in Washington DC weather history. That's right, at 3.22", October is (just barely) wetter than January's 3.21". The driest month is February, with 2.63". Of course, February also has only 28.25 days on average, but even accounting for that, October is nearly 12% wetter than February. The months which have less total precipitation than October are: January, February, April, June, November, December.

Currently, temperatures are near or even a little above 80 in the metro area under sunny skies.

Tonight and Tomorrow

Tonight should see lows in the low 60s with increasing cloudiness toward morning. Tomorrow will be mostly cloudy with highs in the upper 70s.

Tropical Beat

Tropical Storm Tammy developed just off the Florida coast this morning. This is only the 4th time there has been a 19th "named" storm in a single year, and it is the earliest one by almost 3 weeks. The others formed on 12/07/1887, 10/25/33, and 10/27/95 ("Tanya").

At 2pm, Tammy was centered only 20 miles northeast of Daytona Beach, moving north-northwest at 14 mph. By the 5pm advisory, it was 15 miles north-northeast of St. Augustine. Maximum winds had increased slightly to 50 mph, but tropical storm winds extended as much as 260 miles from the center. The strongest winds and heaviest rains were mainly to the north and east.

On the forecast track, the storm should be a depression in central Georgia by tomorrow evening. That's when things start to get interesting for us. There is a lot of moisture associated with this storm, and indications are that it will be moving northeastward as the high pressure ridge now over us moves slowly eastward off the coast. The global forecast model ("GFS") from this morning's data has some light rain reaching the area as early as tomorrow afternoon, but the heavier amounts don't arrive until Friday morning. The latest model ("NAM") output from this afternoon's data delays the arrival of precpitation until midday Friday and keeps the heaviest amounts in eastern North Carolina and central Virginia. The official NWS precipitation forecast ("QPF") made early this afternoon has 2" to 3+" of rain in the local region for the 24 hours from tomorrow evening through Friday evening.

At this point, I don't have a lot of confidence in either the exact timing or the amount of rain, but this is the best chance we've had in at least about 6 weeks to get some serious precipitation in the Washington area. Stay tuned tonight and tomorrow for updates as the situation develops.

Monday, October 3, 2005

Falling Back to Summer

Yesterday's official high of 82 was consistent with the long-term average for the early days of September, and temperatures this afternoon are approaching similar readings in the Washington metro area. Fortunately, dewpoints in the mid 50s are keeping comfort levels more in line with fall than summer.

Tonight and Tomorrow

After lows tonight in the low 60s, some clouds tomorrow should keep temperatures a couple of degrees cooler than today.

Tropical Beat

As Jason predicted below, Stan has been revived by the warm waters of the Bay of Campeche and is now a tropical storm again with maximum winds of 55 mph. An Air Force reconnaissance flight was on the way to investigate early this afternoon. Some strengthening is expected, and Stan could make landfall on the Mexican Gulf Coast as a hurricane.

The area of more interest for the U.S. is a low-pressure trough which extends through the central Bahamas. This has the potential to develop as it moves westward, and a NOAA flight is scheduled for tomorrow.

Bizarro Weather World

The WaPo, which has rarely shown much of an inclination to take science seriously, wastes an entire half-page of valuable A-section real estate today on the latest crackpot scheme for "controlling" hurricanes. This kind of idea, which normally hangs out in the sub-basement along with the perpetual motion machines, cold fusion, and the recipes for transmuting lead into gold, gets trotted out every few years, usually when a major weather disaster has captured the public's attention. This particular plan involves firing off large numbers of jet engines on barges in the path of the storm. The promoter is asking for a mere $10 million to perform an experiment.

Here's an idea: Walk over to Staples, buy a No. 2 pencil for about a dime, and do some arithmetic on the back of the envelope from your latest credit card offer. Prof. Kerry Emanuel, a meteorology professor at MIT who has actually done research on the energy budget of tropical storms, is way too polite when he says, "I hate to sound pessimistic, but Moshe's strategy requires many orders of magnitude of energy more than what he's talking about, and the backfires would have to be almost as strong as the hurricane itself." Unfortunately, even this relatively mild rebuke is buried near the bottom of the second column (second page of web version).

Note to WaPo "science" reporters: It's time to learn your Powers of 10. And while you're at it, why don't you cover something we actually can control, like, oh, I don't know, maybe CO2 emission?

Afternoon Update is taking a break tomorrow, but will resume on Wednesday.

Friday, September 30, 2005

Deja Vu

5:00 update: We have Tropical Depression 19. The area near the Cape Verdes has developed and has the potential to become Stan within 24 hours.

4:30 update
How cold was it? The Official Low last night was 50 (10.0 C). (Hm, I wonder why those numbers sound familiar. Check out the CarTalk Puzzler reference in Monday's post.) The Usually Colder Place was 40 (4.4 C). In case there was any suspense, the 24-hr. precipitation did come in at 0.01", so the record for driest September ever in Washington will be official at midnight. This afternoon, temperatures have rebounded; they are at or very near 70 in all reporting locations. If you want to see rain on a radar, you'll have to go at least as far as the southern Georgia/South Carolina coast.

Tonight and Tomorrow

For tonight, clear skies and calm winds will lead to some more chilly temperatures, but a few notches higher than last night: 53 city to 43 exurbs. Tomorrow: deja vu all over again. (And somebody said in the comments that summer was the boring season!)

Tropical Beat

The tropics continue their siesta. The Special Tropical Disturbance in the northwestern Caribbean was looking better organized today, but not enough to send in the planes. A flight is scheduled tentatively for late tonight or tomorrow.

A low pressure area almost 600 miles west-southwest of the Cape Verde Islands is also perking up and conditions are favorable for tropical depression development "later today or on Saturday", according to the NHC.

Policy Matters

Wonkette has some comments on Michael Crichton's "Jurassic Perk" (or should the initial consonants have been reversed?)

Capitol Climate: CO2

Congress is back in town (hold on to your wallet!), so the American Meteorological Society's Environmental Science Seminar Series resumes on Capitol Hill next Wednesday.
  • Subject: "Changes in Ocean Acidity Resulting from the Buildup of CO2: Implications for the Present and the Future"
  • Time: Wednesday, October 5, 2005, noon - 2pm
  • Location: Dirksen Senate Office Building, Room G-50
  • Moderator: Dr. Anthony Socci, Senior Policy Fellow, American Meteorological Society
  • Speaker: Dr. Richard A. Feely, Supervisory Oceanographer, NOAA Pacific Marine Environmental Laboratory, Seattle, WA
  • Speaker: Dr. Kenneth Caldeira, Department of Global Ecology, Carnegie Institution, Stanford University, CA
The questions to be addressed are:
What are the links between ocean acidity, ocean temperature and elevated atmospheric CO2? What are the implications of increasing ocean acidity in the upper ocean to ecosystems and to society? Is there historical evidence of increased ocean acidity associated with warmer temperatures and higher levels of oceanic and atmospheric CO2? If so, what were the consequences? Are there options for keeping ocean acidity in check? Is the increase in ocean acidity independent of any climate warming resulting from the buildup of CO2?
The next seminar is tentatively scheduled for October 25 on the subject, "Hurricanes: Are They Changing and Are We Adequately Prepared for the Future?"

Thursday, September 29, 2005

Record Breaking

The cold front we talked about yesterday raced through the Washington metro area around noon, bringing some very light showers (National and BWI 0.01", Dulles a trace). Unless something as unusual as an ice meteorite landing directly on the rain gauge happens before midnight tomorrow, the official total of 0.11" will become the new low rainfall amount for September in Washington. (The April record is 0.03", and October has had both a trace and 0.02".) The bright sun after the rapid clearing has pushed the temperature back up to 75 at mid afternoon.

Tonight and Tomorrow

The main issue for the next 24 hours is how many blankets you will need tonight. The model temperature forecasts were not all up to date at press time, but the current ones ranged from 49 to 50 for National, so I will go for 49. (The record of 39 has stood since 1888.) Dulles and the other usual colder suspects could easily be 10 degrees colder. (Dulles has been reporting only for about 45 years, but the record there was 35 in 1993.) Tomorrow's high should be around 70.

Tropical Beat: Not Yet Depressed

After a reconnaissance flight checked out the disturbance in the western Caribbean, the National Hurricane Center put out a Special Tropical Disturbance Statement saying that the area was still disorganized and not yet a tropical depression. Conditions are still favorable, however, and another flight is at least tentatively scheduled for tomorrow.

Policy Matters: Science or Entertainment?

While the Katrina hearings continued on Capitol Hill yesterday, the Senate Environment and Public Works committee was holding a hearing in which, probably for the first time, a science fiction writer was invited to testify on science policy. Michael Crichton, author of "State of Fear", and an M.D. by training, was asked for his opinion on global warming. For a review of the hearing by actual scientists (now there's a novel idea), look at the latest posting on the RealClimate blog. RealClimate has a link to the remarks by the ranking committee member, Sen. Jeffords of Vermont, in which he asks, "Mr. Chairman, given the profound human suffering and ecological damage along the Gulf Coast, why are we having a hearing that features a fiction writer as our key witness?" The hearings were also covered by the book sections of the U.K. Guardian ("Novel take on global warming") and the New York Times ("Michael Crichton, Novelist, Becomes Senate Witness")

Seasonal Outlook

Latest seasonal forecast: Click here.


Latest 3-month temperature outlook from Climate Prediction Center/NWS/NOAA.