Friday, March 17, 2006

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". 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.

Thursday, March 16, 2006

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

Wednesday, March 15, 2006

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.

Tuesday, March 14, 2006

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.

Monday, March 13, 2006

Winds of Change

Updated at 8:30: Tim Flannery, author of "The Weather Makers" mentioned below, will be online tomorrow to discuss his book. You can submit questions ahead of time.

Proceed directly to summer. Do not pass "Go". Do not collect $200. If you disliked Friday's balminess, you're positively hating it today.

Strong southwesterly breezes ahead of a vigorous low pressure area centered near Lake Michigan this afternoon are bringing near-record temperatures to the Washington DC metro area. Mid afternoon readings pushing into the mid 80s would be quite at home in late August, but they are not accompanied by oppressive mugginess; dewpoints are mainly in the mid 50s. Here at Afternoon Blog Central, the Oregon Scientific is now down a couple of degrees from a high of 85. A low rumble turned out to be the bus from the French International School rounding the corner. As Jason explained earlier, this early visitation from summer will be short-lived.

Pictured: The first cherry blossoms appearing around the Washington Monument this morning. By photographer Kevin Ambrose.

Regional radar shows a line of showers and thunderstorms, some with heavy rain, pushing out of the upper Ohio Valley toward western Pennsylvania and the northern panhandle of West Virginia. By 4pm, they were over Pittsburgh, but not yet to Morgantown. Some of these storms may reach the local area this evening or later tonight.

Tonight and Tomorrow

For tonight, showers and possible thunderstorms are likely from the late evening to the early morning hours. Temperatures will fall by morning to the mid 50s. Tomorrow will be much cooler; highs will be only in the upper 50s with a strong northwesterly breeze.

Political Science

Today's unseasonable warmth doesn't prove global warming any more than possible snow flakes later in the week disprove it. However, yesterday's Wapo BoWo featured a cover article jointly reviewing three new books on climate change. The books, Field Notes from a Catastrophe, The Winds of Change, and The Weather Makers, are by two magazine writers and a scientist. They each take different paths through the history and implications of climate change, but they all arrive at a similar conclusion:
The Earth is warming, we're causing it, and that is not at all a good thing.
Needless to say, the review has already provoked a knee-jerk reaction from the oil-industry-funded noise machine. We'll have more to say about countering debunkers with the FAQs in a future post.

Seasonal Outlook

Latest seasonal forecast: Click here.

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