First Snow!

Now

Sunny, cold. As Dan noted in his forecast below, a northwesterly breeze with peak gusts over 35 mph has produced an unusually brisk day for this winter in the Washington metro area. Temperatures reached only the upper 30s in most places; the high of 38° at National was 4° below average, but with the low of 31° the day was exactly average. This cold shot will be quite short-lived, however, as persistent troughiness to the west keeps more cold air from reaching the East Coast through the weekend.

Last night's snow showers were very skimpy in most of the immediate metro area (none observed here in MoCo Update Central), but the photo from Steve Pittman shows the first snow of the season on the ground in the Blue Ridge.

Tonight and Tomorrow

Clear, cold, then becoming milder. Clear skies, low humidity, and diminishing winds near the center of high pressure overnight should allow for some frosty lows in the mid 20s downtown to the upper teens in 'burbia. A quick wind shift to the south and southwest will allow temperatures tomorrow to bounce back smartly to the mid 40s.

For the outlook through the rest of the week and the weekend, scroll on down to Dan's post below.

Climate Corner

The WaPo front page 2006 climate article Dan mentioned in his earlier post has indeed become a top story. At post time, Google reported at least 287 stories on the subject, although, of course, many were reprints of the WaPo, Associated Press, and other syndicated reports. The NYT article, "Agency Affirms Human Influence on Climate", was noteworthy for confirming what we had suspected here at PM Update, that

. . . until yesterday, it appeared that no news release on annual climate trends out of the National Oceanic and Atmospheric Administration under the Bush White House had said unequivocally that a buildup of greenhouse gases was helping warm the climate.

Closer to home, the Baltimore/Washington NWS office in Sterling has released a 2006 Climate Summary detailing some significant aspects of the local climate in the past year. For Washington's 135-year record,

• 2006 was the 8th warmest year
  
• 5 of the top 8 have occurred since 1990
  
• January and December were each in the top 10 of their respective months
  
• April was the 11th warmest
  
• August was the 8th warmest and 22nd warmest of all months
  
• Total precipitation was almost 8.5" above average, the 25th wettest year
  
• There was 1 measurable snow event for the year, Feb 11-12.
  

Oh, yeah, more snow is expected in Seattle.

The Beat Goes On; Some Change in Tune

Now

Cloudy, light showers. A sunny morning has given way to a mainly overcast afternoon and scattered light showers as a very weak "clipper" and its associated upper-level energy move through the Washington metro area. The showers are in the form of snow flurries over the mountains, but to the east, they are mainly of the liquid variety.

Temperatures have peaked in the mid 40s at most locations. Today's range of 47°/32° continues the above-average streak with a +5° departure. The main effect of the clipper's passage will be to provide a reinforcing shot of cold air for the next day or so.

Tonight and Tomorrow

Clearing, cold. After some possible lingering light showers or flurries this evening, skies will clear overnight with lows a couple of degrees cooler than last night: near 30° downtown and low to mid 20s 'burbside. Tomorrow will be sunny and breezy with some scattered clouds and highs near 40°.

For the outlook through the rest of the week, scroll on down to Jason's post below.

Mediarology: Hype, Hype, Hooray!

Unless you've been living in a cave lately, you've been treated to a full dose of media hype-ocracy in the form of "explanations" for the recent warm spell. Many of these rival the profundity of the statement that "Poverty is caused by lack of income." Mainly, they have taken the form of the Point/Counterpoint:

"It's Global Warming, head for the hills!"
"No, Jane, it's just El Niño, and besides, it's snowing like crazy in Denver; nothing to see, just move along!!"

Before PM Update could untangle the ideology and agenda-mongering from the science, however, the climate scientists at RealClimate.org have sorted things out rather nicely in their latest post, entitled, "El Niño, Global Warming, and Anomalous U.S. Winter Warmth". As usual, they have managed to convey some subtle scientific concepts in a form that should be understandable to anyone who is willing to approach the subject with an objective viewpoint.

The El Niño phenomenon was known to oceanographers in the early part of the 20th century, but it was only in the latter portion of the century that serious work was done to associate it with atmospheric effects. Jerome Namias, the legendary father of modern extended-range forecasting, in a paper published about 30 years ago, clearly stated the problem that is still being resolved today:

In large-scale air-sea interactions such as El Niño it is presently almost impossible to prove cause and effect. . . Probably the sea is both slave and master of the atmosphere--a complexly coupled system.

(For the record, the media are apparently not all knuckleheads when it comes to complex scientific problems. NBC News was reported to have managed to keep things relatively straight. Warning: If you click on the preceding link, do not avoid the "About Me" section. You have been warned.)

Graphic courtesy of NOAA and threatdowngenerator.com

Blast From the Past

Now

Sunny, breezy. Temperatures have been falling slightly this afternoon under northwesterly winds gusting over 30 mph at times, but the main change has been in the humidity. While the temperature fell 1° in 6 hours from 9am to 3pm, the dewpoint plunged from 50° all the way to 22° (and 4 more degrees in the next hour). In the meantime, the high for the day reached 56° early in the afternoon.

While dropping only to near average January levels, temperatures in the next couple of days will seem especially cold after the warm spell we've been experiencing. There is even the possibility of some scattered flurries to go along with the more wintry temperatures.

Tonight and Tomorrow

Clear, cold, flurries possible. Under clear skies tonight, lows will range from the low 30s downtown to mid and upper 20s in the 'burbs. Tomorrow will be partly cloudy and seasonably cold, with highs near 44°. There is a 30% chance of some light snow flurries or sprinkles, especially in the afternoon.

For the outlook through the rest of the week, scroll on down to Jason's post below.

Reasoning By Analogy

Analogies are always imperfect, so forecasting from past analogs is a lot like driving while looking in the rear view mirror. Nevertheless, looking at past patterns can provide what the math guys call an "existence proof" and therefore give some clues as to which of the infinite number of possible states of the atmosphere are "preferred." The recent pattern of an upper-level low pressure trough in the West and a high pressure ridge in the East is similar in a lot of ways to the pattern of January 1950, which was by far the all-time warmest January in the 130+ years of official records in Washington. The monthly average of 48° that month was more than 1° higher than the second highest January in 1932 and more than 4° higher than the third place holder, 1890. January 1950 was responsible for 5 daily temperature records which stood until this year. The record for the 6th is the one which was broken on Saturday.

The chart shows the daily highs and lows for January 1950, along with the trend of the month-to-date average for that year and the average for this year so far. Note that after building warmth in the first week, January 1950 went through a series of progressively cooler cycles through the second and third week, finally culminating in the all-time warmest Washington January day, 79° on the 26th. That day was so spectacular that it got its own article in the Monthly Weather Review. The pattern finally broke down during the middle of February.

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

Mediarology: Capitol Climate

Today's Diane Rehm Show on WAMU (88.5 FM) featured a discussion of the prospects of climate policy action in the new Congress. Guests were: John Fialka, environment and energy reporter for "The Wall Street Journal"; Felicity Barringer, reporter, New York Times; Sen. Jeff Bingaman, (D-NM), new chair of the Senate Energy Committee; James Connaughton, chair, White House Council on Environmental Quality. Streaming audio is available online, and the show is scheduled to be rebroadcast tonight at 9:00.

Also from NPR were reports yesterday on the impact of this winter's temperatures on central Maine and an interview with Robert Henson, author of "The Rough Guide to Climate Change".

Plants to People: Chill Out!

Now

Cloudy, damp, mild. After this morning's showers, it's a foggy, misty afternoon here in the Washington metro area, but temperatures are quite mild for the season, generally in the upper 50s and low 60s. A few more showers, and possibly thundershowers, will give way to near-record temperatures tomorrow while a more seasonable cold snap gathers on the horizon for the early to mid part of next week.

Tonight and Tomorrow

Showers ending, near-record warmth. There is a 50% chance of showers, possibly scattered thundershowers, overnight with lows only in the mid to upper 50s. Clouds will give way to sunshine during the day tomorrow with highs near 70°.

For the outlook through the rest of the weekend, scroll on down to Jason's post below.

Plant Patrol

An article, "Kept From Hibernation By a Lingering Warmth", in today's WaPo Metro section surveys the recent unusual (and more usual) blooming patterns of the region's gardens. It quotes several local experts as saying that the plants will still be able to survive when the inevitable cold snap (and there will certainly be one) does occur.

Mediarology: Hype-ocracy

Having rerun all possible past disasters into oblivion, The Weather Channel is rolling out a new series of imaginary disasters The Day After Tomorrow (Sunday, 9-10pm). According to the on-air promos, these are the cities scheduled to die to the tune of a continuously pounding soundtrack in the new season of "It Could Happen Tomorrow": St. Louis (F5 tornado), Chicago (F5), Austin (wildfires), Houston (Cat 5 hurricane), Las Vegas (8.0 earthquake). The state of Hawaii is also scheduled to be demolished via tsunami, and there is an untitled shot of a crumbling Capitol dome under a looming presumably F5 attack. The TiVo on-screen schedule shows the Chicago and Houston programs to be the premiere back-to-back episodes of the new season.

Last January, when this series first went on the air, PM Update cautioned that the continued blurring of the line between news and entertainment can lead to a "cry wolf" effect that threatens to outweigh the possible educational benefits. The Weather Channel's Climate Code, which also debuted last year, is a very different kind of show, but it has sometimes been criticized by being lumped together in the same category. It has gone to great lengths to be objective and non-partisan (or at least bi-partisan; a Democratic and Republican governor were interviewed in the same segment), but it has still been accused of having a ratings-driven agenda. If this show is driven by ratings, why was it put on at 5pm Sunday . . . during football season?

Another example of the confusion between reality and image is the reaction to last year's documentary, "An Inconvenient Truth." It has been attacked for hyping a 50-ft wall of water demolishing New York. Guess what? The drowning Statue of Liberty was in a completely different movie, although a comparable scene was used to promote "It Could Happen Tomorrow." If you're keeping score at home, turn to scene 21, time 1:00:23, of the DVD, to see how New York is presented. For reference, here is what the book, which is an extended version of the movie script, says about Manhattan (starting on page 196):

"If Greenland melted or broke up and slipped into the sea---or if half of Greenland and half of Antarctica melted or broke up and slipped into the sea, sea levels worldwide would increase by between 18 and 20 feet. . .
[quotation from Tony Blair's advisor]
[several pages of illustrations of Florida, San Francisco Bay, Netherlands, Beijing, Shanghai, Calcutta, Bangladesh]
. . . the picture at right shows what would happen to Manhattan if sea levels rose 20 feet worldwide. The site of the World Trade Center Memorial would be underwater. Is it possible that we should prepare for other serious threats in addition to terrorism? Maybe it's time to focus on other dangers as well."

Which particular part of that includes the hysterical 50-ft wall of water?

The plants may be more rational than the humans.

Temperature Temperance

Now

Sunny, mild. Under some scattered high clouds and a southerly breeze, temperatures have reached the 60s this afternoon in the Washington metro area; the official high was 62°. Clouds will increase tonight, and showers will arrive tomorrow, as a low pressure area developing along the Gulf Coast moves toward the Ohio Valley.

Tonight and Tomorrow

Increasing clouds, mild; showers developing. Clouds will increase tonight with lows in the upper 40s to 50°. Showers will develop after dawn tomorrow morning, continuing through the afternoon. The heaviest rain, however, should remain west of the mountains and through the Ohio Valley. Highs will be in the low 60s.

For the outlook through the weekend and beyond with Larson's Long-Range, scroll on down to Josh's post below.

Warmth in Perspective

While today's temperatures certainly felt out of place for January, they were well short of the record 73° for the date. In fact, only 4 dates in January have failed to ever reach 70° in Washington. (Interestingly, this is 2 fewer than the 6 in December.) Two of them have already passed, including the lowest, 68° on the 3rd. What is noteworthy about the current warmth, however, is its persistence. The current string of 25 consecutive above-average days is longer than last January's run. Although there were only 3 average or below days in January 2006, they were scattered through the month.

The warmth is also pervasive through the whole country. The plot above of temperatures at midnight last night (from Unisys) shows only a very small extent of sub-30° temperatures (blue and blue-green), nearly all in the southern Rockies. The daily high temperature map shows above-freezing temperatures in all 48 states. I could find only 4 locations with temperatures below 32°. If you can find more, please let us know in the comments where they are located.

Modeling Myths

A common myth, especially, it seems, among operational meteorologists, is that climate models must be inaccurate simply because daily forecast models become inaccurate beyond about a week with current technology. Therefore, the argument goes, how can you possibly forecast years, decades, centuries into the future? A "Quick Study" in the latest (January 2007) issue of Physics Today called "The physics of climate modeling" helps to explain this apparent paradox. The article is open to non-subscribers and is quite accessible, no equations necessary. The key distinction between the two types of models is the following:

Weather concerns an initial value problem: Given today's situation, what will tomorrow bring? Weather is chaotic; imperceptible differences in the initial state of the atmosphere lead to radically different conditions in a week or so. Climate is instead a boundary value problem-a statistical description of the mean state and variability of a system, not an individual path through phase space. Current climate models yield stable and nonchaotic climates, which implies that questions regarding the sensitivity of climate to, say, an increase in greenhouse gases are well posed and can be justifiably asked of the models.

Unfortunately, the online version omits a figure from the carbon-based version which shows how well climate models are able to reproduce the effects from the eruption of Mt. Pinatubo in 1991, although the results are described in the text. Hopefully this will appear in the pdf version, which is not yet online.

Also pertinent to this question is the article "Belief and knowledge-a plea about language" in the same issue. It discusses how different meanings for the same words can produce misunderstandings about scientific concepts. Saying "I don't believe the results of climate models" without verifiable contrary data is simply an ideological assertion. On the other hand, the statement, "[Scientists believe that] climate is changing in many ways, and there is strong observational and scientific evidence that, at least over the last 50 years, human activities are the major contributor to climate change," reflects the current state of scientific knowledge.

24 Days and Counting

Now

Clear, mild. After a frosty start, it's a brilliantly sunny mid March day here in the Washington metro area. The official high was 56°, equal to the climatological average high for March 16-18. This is now the 24th consecutive day of above-average temperatures, and there are at least several more on tap. The PM Update mobile unit observed numerous walkers, joggers (note to spellcheck: not jokers!), and bicyclists enjoying the conditions along Beach Drive in the Kensington-Bethesda area early this afternoon.

Tonight and Tomorrow

Continued seasonably mild; some increase in clouds. Under mainly clear skies, low temperatures tonight will be in the upper 30s downtown to near freezing in the 'burbies. Clouds will increase somewhat tomorrow, particularly late in the day, with highs near 60°

For the outlook through the weekend, scroll down to Dan's post below.

The Trend is Your Friend?

The trend is definitely not your friend if you're a snow-lover. As we've cautioned many times, however, "past performance is no guarantee of future results". Matt recapped December in his Tuesday post. The chart to the right summarizes the temperature part of the story. Note the 2 daily record highs, but also the fact that the linear trend (dashed line) of the highs is actually slightly upward, despite the usual downward trend of the average during the month.

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

Science Fact and Fiction

Dan poses the intriguing question of what Washington would be like under a different climate in his earlier post. For a really far out consideration of this question, check out the science fiction section of the new CapitalWeather.com store. Kim Stanley Robinson's trilogy is based right here in a future DC. The second volume comes out in paperback at the end of the month and is available for pre-order; the third book is scheduled for release in February.

In case you missed it, let me repeat that this is fiction, although the first one (I haven't yet read the other two) is much more plausible than, say, "The Day After Tomorrow." Unlike some people who run energy industry lobbying operations from their $1.2 million Potomac homes, we are extremely careful here at CapitalWeather.com to separate fact from fiction. Like alternative histories, however, alternative futures can often provide interesting and useful insights.

December Extender

Now

Clear, mild. Despite northwesterly breezes, temperatures reached 50° or higher throughout the Washington metro area this afternoon. The official high was 51°; the low so far of 42° is just 1° below the average high for the date and 43° above the record set in 1899. BWI and Dulles were both at 50°. The national weather map shows high pressure from coast to coast with the only significant precipitation in the Pacific Northwest and extreme northern Rockies.

Tonight and Tomorrow

Continued clear and seasonably mild. Clear skies should continue through tomorrow, with lows tonight from the mid 30s downtown to the upper 20s in 'burbland. Tomorrow will be even milder than today, highs near 57°.

For the outlook through the rest of the week, scroll down to Jason's post below.

Season of Lights

The upcoming seasonably mild and dry evenings provide a last chance this week to enjoy the Garden of Lights display at Brookside Gardens in Wheaton. The scenes displayed in lights include a rainstorm, lightning, and a rainbow. Even with over 600,000 lights, it was a little hard to tell in the dark, but some kind of cherry-like tree was in full bloom there last night. That would be consistent with reports from several site visitors in recent days and an article ("Trees Abloom Amid Winter Warm Spell") in yesterday's WaPo.

ISO Snow IV

If nothing else works, try a time machine: The 1780 major East Coast snowstorm noted tersely in "Today in Weather History" was the second of three major nor'easters from Virginia northward over a 10-day period which "rank with the greatest such combinations in our meteorological history", according to the definitive work on the subject, "Early American Winters", by David Ludlam. Following these storms, snow covered the fence tops in southern Connecticut and depths in the woods were 42-48 inches. Drifts were estimated at 6 to 10 feet in New Haven, on the coast.

Political Science

In an impressive display of journalistic ambidexterity, today's carbon-based WaPo has an article both above ("Arlington Takes On") and below ("Global Warming") the fold. It describes the actions of the Arlington County Board in reducing CO₂ emissions. We'll leave it to the tin-foil-hat types to decode the agenda, but the article is written by the Arlington/Alexandria reporter, while the erstwhile environment reporter returns to her former political beat to take the page A1 pole position with an article analyzing the House Democrats' legislative plans in the new Congress.