Wind-ing Down

At least there's no wind with the chill. Late March sun through a high overcast in the Washington DC metro area is pushing temperatures this afternoon a degree or 2 higher than yesterday's below-average high of 51. Clouds and a chance of showers are likely through much of the weekend as weak disturbances rotate southeastward around a persistent upper-level low now centered over the Great Lakes. Meanwhile, a surface low lurking off the Carolina coast is modeled to deepen vigorously by Sunday afternoon. As it remains well off the coast, however, its effects on the local area are expected to be limited to reinforcing the flow of cold air with its counterclockwise circulation.

North American 500 mb height (colors) and surface pressure (solid lines) this morning from Unisys

Tonight and Tomorrow

Under cloudy skies tonight, lows will range from near 40 city to upper 30s 'burbs. Clouds will continue tomorrow with highs in the upper 40s, a couple of degrees warmer if more sun breaks through. There is a 30% chance of light showers tonight, 50% tomorrow.

March Winds

The month so far has lived up to March's reputation as the windiest month, but the overall average of 11.5 mph is only slightly higher than the long-term average of 11.1. The peak gust of 45 mph on the 15th is less than the 52 mph recorded in 2002. The maximum 2-minute wind of 36 mph (not shown) was also exceeded in 2002.

CapitalClimate chart from NWS data, photo © Kevin Ambrose

Happy WMD!

Have you thanked a meteorologist today? It's World Meteorological Day, the anniversary of the founding of the World Meteorological Organization in 1950. This year's theme is "Preventing and Mitigating Natural Hazards". The WMO Secretary-General's message notes that 90% of natural disasters involve weather, climate and water. During the 10 years ending in 2001, natural disasters were linked to 622,000 deaths worldwide; the damage from hydrometeorological disasters was estimated at $446 billion.

Chilly but dry conditions continue across the metro Washington DC region this afternoon with temperatures near or a little above 50. The near-term outlook is well covered in Josh's earlier post, so let's take a longer-range view (about 130,000 years).

Hot off the Press Release

Earlier this afternoon, the National Center for Atmospheric Research (NCAR) in Boulder announced the publication of 2 papers by NCAR scientist Bette Otto-Bliesner and University of Arizona Environmental Studies Laboratory Director Jonathan Overpeck in tomorrow's issue of the journal Science. While not a smoking gun, the new studies help build a picture of the potentially catastrophic consequences of global warming. Combining paleoclimate records (such as ancient coral reefs and ice cores) with output from the NCAR Community Climate System Model (CCSM), the researchers found that a 5-8° F warming of Arctic temperatures by the end of this century from increased greenhouse gases would produce conditions as warm as those of 130,000 years ago. That was the period between the last great ice age and the previous one, when sea level was 20 feet (6 meters) higher than today. This is a much faster rate of sea-level rise than has previously been assumed.

The notion of abrupt climate change was unfortunately distorted out of all recognition by the recent movie, "The Day After Tomorrow", but it has been receiving much more serious attention in the last decade. The graph, from a National Academy of Sciences report, "Abrupt Climate Change", shows a very rapid warming from the so-called "Younger Dryas" period about 12,000 years ago. At that time, the temperature increased by 8° C in only a decade.

Dr. Overpeck presented an excellent overview of the abrupt climate change theory in a lecture at the American Geophysical Union (AGU) annual meeting in 2002. For some other intriguing speculation on modes of climate shift, check out the Charney lecture by MIT Prof. Kerry Emanuel (of hurricane intensity fame) from 2001. The AGU lecture archives, which I just discovered yesterday, are a treasure trove of interesting material from AGU meetings back to 1999. The two which I have sampled so far should be quite accessible to a general audience.

Spring of Our Discontent

After such an underachieving winter, what was already featured as a low-potential system created some excitement among the snow-lovers as it approached the Washington DC metro area today. Unfortunately for the flake fanatics, the extreme dryness at the surface won out over all of the other factors. Actually, no matter where you were in the metro area, you were probably no more than a mile or so from some moderate snow. The only catch is that it was straight up, and most of it evaporated before reaching ground level.

Around noon, radar truthfully showed snow falling nearly everywhere within about a 30-mile radius of the Washington Monument. The radar image above from weather.com shows snow across most of the area around noon. The surface map to the right from College of DuPage around the same time shows light snow falling in Washington, but a large area of 20° and lower dewpoints from the Mid-Atlantic region across the Northeast and back into the Great Lakes. After 2 hours of light snow, National was able to eke out 0.01" of precipitation at temperatures of 33-34°.

Remember, we told you yesterday that the devil was in the details. Ultimately, the models were just a little bit too strong on the moisture. Having said that, the models are still hinting at a little more light snow or flurries tonight, especially in the mountains, as the upper-level energy now over the Midwest and Ohio Valley moves eastward and out to sea.

The big story here is the fact that we have now had only about 1% of average precipitation in the last month and only about 10% in the last 6 weeks, with a mere 0.04" so far in March. If we don't get some soon, we will be looking at serious drought conditions going into the warmer part of the year.

Tonight and Tomorrow

For tonight, there is a slight chance of some light snow showers or flurries. Clouds will decrease toward morning with lows near 29. Tomorrow will be sunny with highs in the upper 40s.

Tropical Topics

With a little over 10 weeks before the official start, it's not too soon to start thinking about hurricane season. The Southern Hemisphere season is in full swing now. The AP graphic via BBC shows Cyclone Larry, a Category 5 storm, slamming ashore in Northern Queensland, Australia on Monday, local time. Fortunately, there were no reported deaths despite the severe damage from winds up to 180 mph. A second storm, Cyclone Wati, is now approaching the coast as a Category 3. It is forecast to intensify but remain offshore.

Closer to home, AccuWeather is going for the hype by touting the likelihood of a hit on the East Coast. In his typical low-key style, Joe Bastardi is quoted saying, "The Northeast is staring down the barrel of a gun."

PM Update will be taking off tomorrow to work on a global warming story so hot it is embargoed for release until 2pm on Thursday.

Happy Dry St. Patrick's Day!

Now, there's a contradiction in terms. The local watering holes will be doing their best to remedy the situation, but the nearly 5-week-long dry spell continues in the Washington DC metro area. The weak low pressure area moving through south of us last night was even wimpier and drier than we were hinting at yesterday. Radar showed some bands of precipitation over the area, but nearly all of it failed to penetrate the very dry air closer to the surface.

The map of 24-hr. precipitation from Unisys shows only one report of as much as 0.01" east of the mountains. Alone of the 3 major regional reporting locations, National reported a trace of light rain from around midnight to 2am, leaving the total for the month since mid-February at a little over ¼".

CapitalWeather.com chart from NWS data, photo © Kevin Ambrose.

There have been only 4 Marches in 135 years in Washington with less than 1" of precipitation, and we are now at 3% of that amount. The most recent March under 1" was 1986 with 0.74".

With the extensive clearing this afternoon, temperatures range from 50° to the low 50s across the region.

Tonight and Tomorrow

Under clear skies and light winds, lows tonight should fall to the low 30s in town, upper 20s in the cooler 'burbs. Tomorrow will be sunny and a bit cool for the season, highs in the upper 40s.

Winter Jumps the Shark

"Jumping the shark" has become synonymous for "passing one's prime", and this winter certainly seems to have jumped the shark for DC area snow lovers with the storm of Feb. 11-12. That doesn't mean that the chance of seeing any flakes is totally gone, however. (That may be a bit hard to believe with temperatures pushing near 60 in most of the region this afternoon.)

The current situation is an interesting case of the classic "over the mountains" Washington forecast dilemma. A disturbance which originally impacted the West Coast a few days earlier has regrouped in Colorado and marched across the Plains to be centered in Illinois early this afternoon. Supported by a small, but vigorous, area of upper-level energy, this storm has been forecast by the models to bring a narrow band of precipitation down the Potomac Valley or a bit to the south. The latest model run this afternoon brings a very narrow band of up to ½" of precipitation directly across the DC area, shown on the map as the darkest green area. Despite the lateness of the season, there is an ample supply of cold air provided by the large circulation around the low pressure area in eastern Canada we noted yesterday.

So, let's review the recipe from the kitchen of Momma Nature's Weather Grill:

1. Surface circulation? Check, but expected by the models to weaken.
   
2. Upper-level energy? Check.
   
3. Cold air? Check.
   
4. Moisture? Well, not so much. This system seems to be moisture starved. While it has brought a trace of wet snow to Chicago today, it doesn't seem to be able to tap into moisture from the Gulf of Mexico. Dewpoints ahead of the storm from the northern Gulf states through Tennessee and Kentucky were only in the upper 20s earlier, although there is a wedge of more humid air extending northeastward from the summer-level juiciness along the western Gulf Coast (mid 60s in Houston, for example).

The bottom line: There is virtually no chance of accumulating snow inside the Beltway, but many areas could see flakes falling, and there is the possibility of a coating, especially on grassy areas, in the higher elevations to the north and west.

Tonight and Tomorrow

For tonight, increasing clouds this evening will be followed by light rain or mixed rain and snow by morning; lows will be in the upper 30s in the city to low and mid 30s in the 'burbs. There is a 60% chance of measurable precipitation. Light snow or mixed precipitation will end in the morning, followed by decreasing cloudiness in the afternoon and highs well below average for this time of year, in the mid 40s.

Omnimedia: TWC Jumps

Exactly when the Weather Channel jumped the shark is debatable, but any remnant of a doubt that this had occurred was removed yesterday, when rumors swirled that winter weather expert Paul Kocin had left the network. This was confirmed last evening when PK himself posted the news that his position had been eliminated.

If my count is correct, that leaves Heidi Cullen (climate), Greg Forbes (severe weather), and Steve Lyons (tropical) as the only remaining on-air experts. With TWC's increasing emphasis on fluff over substance, even that small number is likely to be reduced soon unless Steve Lyons has gotten a hair transplant or become pregnant in the off season. It's been apparent for some time that the Weather Channel was following its cohorts in television "news" by dumbing down content in pursuit of that ever-elusive demographic: stupid people. It's a shame that TV producers have such a low estimation of the public's desire to be educated as well as entertained.

When do you think the Weather Channel jumped the shark, and what should a "Real Weather Channel" look like?

Photo from weather.com

Arctic Flows and Floes

A complex low pressure area stretching from near the mouth of the St. Lawrence River to Greenland is helping to funnel Arctic air down the entire East Coast today. In the Washington DC area, however, strong winds last night under a bright full moon kept the official low from dropping below 40&deg. A few miles outside the Beltway here at Afternoon Blog Central, the low was 38°.

This afternoon, temperatures have risen into the 50s, but the northwesterly wind gusting as high as 40 mph has quite a bite to it. The strong winds and low humidity have prompted a red flag warning for potentially dangerous fire weather conditions. (Note to Ft. Belvoir: Yes, it's extremely dry, but your dewpoint readings have lately been running about 10° or more lower than your neighboring reporting locations. It might be time to check the robo-observer.)

Surface weather map at 1pm today from HPC/NCEP/NWS

Attention now shifts to the low pressure area making its way eastward from near the corner of Colorado, Nebraska, and Kansas. As it passes south of our area, it brings the likelihood of some precipitation late tomorrow night or Friday morning. The latest model run this afternoon is weakening the storm circulation as it approaches the coast, and the precipitation is having a hard time making it over the mountains. The temperatures at upper levels, however, are favorable for at least some snow to fall, although the prospects for accumulation are limited. This is somewhat at odds with the stronger results in the morning model runs, so the situation bears watching, especially for the Friday AM rush hour.

Tonight and Tomorrow

For tonight, winds will diminish somewhat; lows under mainly clear skies will be in the low to mid 30s in the city, with some upper 20s in the colder 'burbs. Tomorrow will be sunny with highs around 55.

Climate Notes

An article in today's NY Times describes the failure of Arctic sea ice to re-form this winter to its normal extent. This is leading to predictions of record-breaking areas of open water this summer.

Meanwhile, a report from the Earth Institute at Columbia University analyzes the history of Scandinavian ice sheet melting during the end of the last ice age. The joint research by scientists from Columbia, Oregon State, and 8 European institutes found that there was an intermittent pattern of ice accumulation and melting as temperatures warmed, eventually leading to a rapid disintegration of the ice sheet once temperatures warmed enough.

And Now for Something Completely Different

After a brief blast of summer, here's a novel idea: March temperatures. Today's high will go into the record books as midnight's reading of 74, but temperatures have been falling or nearly steady since then, down to the upper 50s by mid afternoon. Winds behind the cold front which finally went through early this morning have been strong from the northwest, gusting near 40 mph.

The rain showers which accompanied the front were very weak; only a trace fell into the official rain bucket, although Dulles managed to pick up 0.02". We are now in a month-long dry spell. Only 0.03" of precipitation has been observed at National up to mid-month, and a mere 0.25" was reported in February following the snowstorm on the 12th.

Tonight and Tomorrow

Tonight will be much more March-like, with lows around 36 under mostly clear skies, a few degrees cooler in the outlying areas. Tomorrow will be sunny and breezy with highs in the mid 50s.

NOAA's New Digs

Here's something else different: After decades of residency in sunny Suitland at FOB #4 and later at the World Weather Building in Camp Springs, NOAA broke ground yesterday for the Center for Weather and Climate Prediction at the University of Maryland's M-Square Research and Technology Park in College Park. The nearly 270,000 sq. ft. building will be the new home of the 800 people who make up the Satellite and Information Service, Air Resources Laboratory, and the National Centers for Environmental Prediction (NCEP). NCEP collects and analyzes worldwide meteorological data, develops and runs the numerical weather prediction models we look at here every day, and does climate analysis and prediction.

Having first trod the hallowed halls of FOB #4 more than 4 decades ago, I wish the members of NCEP good luck in their well-deserved move to improved facilities at their new $50 million home beginning in late 2007. Full occupancy is planned for February 2008. Besides including state-of-the-art technology, the building plan qualifies for U.S. Green Building Council LEED Silver Certification for sustainable buildings.