Friday, March 10, 2006

This Preview Approved for All Audiences

6:00 Record Update: NWS reports that Dulles also broke the record with 78, BWI tied at 77, and Salisbury broke the record with 77.

PM Update was sorely tempted to play hooky today, but no true weather geek can escape the alluring sound of records crashing. The window is open, and the sweatshirt is off here at Afternoon Blog Central, where the temperature has zoomed to summer-like levels, and the local shopping center is advertising a "Beach Party" promotion.

What a difference a month makes. Exactly 4 weeks ago, we were contemplating a major snowstorm for the Washington DC area. Now we've jumped ahead to temperatures which are typical of the average in late May.

Strong southwesterly breezes were aided by the bright near-equinox sun as the 78° temperature broke a 42-year-old record in Washington DC this afternoon. Dulles at least tied its record of 77° from 1986. The record readings were part of a surge of warm air which brought 60+ temperatures well up into the Hudson Valley and southern New England ahead of a low pressure area racing northeastward from the Great Lakes to Quebec.

Temperature chart at 3pm today from Unisys

The best part of the early-season heat wave was the humidity, or rather the lack of it. Dewpoints were in the upper 30s throughout the region (37° was a very popular number at 4pm), so afternoon relative humidities were in the 20s.

With the passage of a "cold" front, temperatures will pull back from record territory tomorrow, but a very pleasant weekend is on tap for the area. The air behind the front is of Pacific origin, so 70+ temperatures are likely again before the weekend is out. chart from NWS data, photo © Kevin Ambrose

Tonight and Tomorrow

Tonight, temperatures will fall to lows near 50 in the city to mid 40s in the 'burbs under scattered clouds. Tomorrow should be partly cloudy in the morning with clouds increasing during the afternoon and highs in the upper 60s.

Thursday, March 9, 2006

Spring Fever Warning

Get your excuses ready for skipping work tomorrow: Strong southerly flow ahead of a multiple-center low pressure area in the Mississippi valley is bringing warmer temperatures to the Washington DC region this afternoon. By mid afternoon, many locations had reached the upper 60s, but the notorious south wind effect off the Potomac was keeping the official National Airport reading at 63. Even there, however, it jumped to 67 the following hour. Here at south-facing Afternoon Blog Central, the indoor-outdoor Oregon Scientific is showing "6" for 5 out of its 6 digits.

Further south, 70s were widespread from southern Virginia across North Carolina. The regional radar is nearly totally dry as the precipitation associated with the low stretches from the lower Mississippi valley up through the Great Lakes. Included with that precipitation were some severe storms.

Temperature chart at 3pm today from Unisys

Tomorrow should see a widespread outbreak of the highly contagious seasonal malady known as Spring Fever across cubicles throughout the region. In case the Afternoon Update doesn't appear tomorrow, you'll know why. If you haven't taken your lawnmower in for a tuneup yet, now is the time; the backlog was already 3½ weeks when I brought mine on Tuesday.

There are only a handful of days in March with record highs below 80, and one of them is tomorrow. The record for the 10th was 77 in 1964. This is undoubtedly safe from being broken, but we should at least be within shouting distance.

Tonight and Tomorrow

Mostly cloudy skies tonight should keep low temperatures within a few degrees of the long-term average high for today, which is 53. There is a 20% chance of showers late at night or tomorrow morning. More sunshine tomorrow afternoon should help push temperatures into the low 70s.

Art and Science

The RealClimate blog has an interesting new post on the reflection of climate in art. It includes a discussion of the artistic license expressed by the ice depicted in "Washington Crossing the Delaware."

Wednesday, March 8, 2006

Not the March of the Penguins

Today's temperature map shows signs of the coming season as the 60-degree line reaches the Virginia-North Carolina border. Closer to home, temperatures in the Washington DC metro area are in the low 50s at mid afternoon. Cloud cover has increased, but the nearest showers on radar are in far southwest Virginia and southern West Virginia.

Temperature chart at 3pm today from Unisys

Tonight and Tomorrow

Tonight will be cloudy with a 25% chance of showers; lows will be near 40. Temperatures will rise with a southwesterly breeze tomorrow as clouds decrease after a slight chance of showers early in the day. The exact high will depend on how much sun breaks through in the afternoon; anywhere from 62 to 67 is quite possible.

March Snow chart from NWS data, photo © Kevin Ambrose

Despite the chilly start, this month is not looking like the March of the penguins. I'm sure Josh will have more to say about this in his post tonight. Meanwhile, a look back shows that while it is relatively rare, March snow in Washington is not unique. The average March total for the entire period of record in Washington (downtown and airport) is only 1.6". On the other hand, every date in March has seen a snowfall of at least 1.5" at some point. Interestingly, the highest daily total of 11.5" fell as late as the 29th in 1942. That storm also accounted for the entire month's total that year.

This decade has been particularly scanty, with an average monthly total in March of less than 0.2". The last century closed out with 8.7" in 1999, but the last time 10" or more fell was in 1960, when the second-highest March total of 17.1" occurred, including the record for the date of 7.1" on the 3rd. Today's record snowfall was 5.8" in 1911. That month had a total of 8".

Monday, March 6, 2006

Looking for Regime Change

A feeble low pressure area scooting eastward to the Atlantic across North Carolina is bringing clouds and some patches of light rain or drizzle to the Washington DC metro area this afternoon. In the far western Maryland panhandle and north of the Mason-Dixon line, the isolated precipitation is of the frozen variety. Temperatures ranged from the upper 30s in a few spots to the low and mid 40s at mid afternoon.

As the week wears on, warm high pressure building over the center of the country will be signaling a regime change which will reverse our recent string of mostly cooler than average days.

Tonight and Tomorrow

There is a slight chance of showers or snow flurries through this evening; lows tonight will be near 30. Clearing tomorrow will be accompanied by high temperatures still on the cool side for this time of year, around 47.

Political Climate

Friday's WaPo had a front page article, "Antarctic Ice Sheet Is Melting Rapidly", describing the results of a new study of Antarctic ice mass decreases. The research, using an innovative technique acronymed GRACE, involved measuring small variations in Earth's gravity detected by a pair of satellites flying in tandem along the same orbit. Articles about the results also appeared in:
The BoGlo reprinted the WaPo article.

Reaction from the usual oil-industry-funded suspects was quick and predictable. Also just in the nick of time to save us from the facts, Situational Science Man made an appearance in yesterday's Doonesbury.

Seasonal Outlook

Latest seasonal forecast: Click here.

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