Friday, April 28, 2006

Getting Better All the Time

This afternoon's weather map shows a cool, dry high pressure area centered over southern Canada and dominating the entire Atlantic coast. Despite the northerly breeze veering somewhat easterly at times, the entire Washington metro region was enjoying sunny mid 60s temperatures by mid afternoon. Even the Bay and Eastern Shore locations were mainly over 60, although Ocean City was a brisk 57 with a northeasterly wind gusting to 26 mph. Today's models are unanimous in saying that Camden's earlier weekend assessment may have been a bit pessimistic; the sunny and dry conditions are predicted to continue right on through Sunday.

Surface weather map and satellite picture at 2pm today from HPC/NCEP/NWS

Tonight and Tomorrow

For tonight, clear skies and light winds should allow temperatures to drop to the mid 40s city, as low as the mid 30s in the colder 'burbs. Tomorrow earns the Seal of Approval, although the high near 67 under sunny skies will be only marginally "room temperature".

Tropical Topics

As the clock ticks down to the beginning of another tropical season, the American Meteorological Society's 27th Conference on Hurricanes and Tropical Meteorology is winding up today in Monterey, CA. There have been a number of interesting presentations, especially on the controversial issue of the relationship between global warming and hurricane activity.

Colorado State University's Dr. William Gray, whose claim to fame appears to be mainly based on statistical forecasting, goes out on a limb with his strong denial of any connection. His presentation is certainly "in your face"; the introduction is a quote from an ideologically partisan oil-state senator and the closing is a statement from the public relations person of the American Association of Petroleum Geologists about a science fiction book. Gray's scientific assertions regarding the oceanic thermohaline circulation (THC) are thoroughly demolished at, where a spirited discussion has generated over 60 comments in the last couple of days.

MIT Prof. Kerry Emanuel, author of the recent book Divine Wind, is a joint author with two researchers from the University of Miami of a paper, Could hurricanes form from random convection in a warmer world?. This study uses physical modeling to assess whether increases in sea-surface temperatures could induce spontaneous generation of hurricanes without the usual prerequisites.

Abstracts for all the conference presentations, as well as many extended versions with graphics, are available on the conference web page.

Thursday, April 27, 2006

FEMA Found FUBAR; Weather Not

Yesterday's cloud-enhanced chill in the Washington DC metro area has been replaced by much more seasonable readings. Wednesday's official high of 59° was the lowest since the 57° on the 9th, but nearly all locations were at or above 70 by mid afternoon today ahead of a cold front bringing a reinforcing shot of cooler air for tomorrow. chart from NWS data, photo ©
Kevin Ambrose

Tonight and Tomorrow

Tonight will be variably cloudy with lows from the upper 40s to near 50 in the city and lower 40s in the cooler 'burbs. Tomorrow will be mostly sunny with highs around 66, but northeasterly winds could bring in more clouds and cooler temperatures east of the immediate metro area.

Preparedness Disaster

The AP reports via the online WaPo that the Senate Committee on Homeland Security and Governmental Affairs has recommended that FEMA be abolished and replaced by a National Preparedness and Response Authority. The committee report concludes that
1) long-term warnings went unheeded and government officials neglected their duties to prepare for a forewarned catastrophe; 2) government officials took insufficient actions or made poor decisions in the days immediately before and after landfall; 3) systems on which officials relied on to support their response efforts failed, and 4) government officials at all levels failed to provide effective leadership.
Notice the emphasis on the fact that the catastrophe was "forewarned". The meteorological community, and especially the staff members of the National Hurricane Center, can take pride in the recognized excellence of the forecasts leading up to the storm's landfall. The report singles out the "strongly worded advisories from the National Hurricane Center (NHC) and personal warnings from NHC Director Max Mayfield".

Meanwhile, Reuters reports that the White House is opposed to the committee's recommendation that FEMA be scrapped. Hurricane season officially begins in 34 days.

Tuesday, April 25, 2006

Dry Afternoon; Liquid Likely Later?

The rain associated with a strong cold front and a weak low pressure area approaching from the Ohio Valley had made it only as far as the Pittsburgh area by mid afternoon today. Current indications are that showers will continue to develop along the front, but any rain in the Washington metro area is likely to hold off until the low pressure area swings eastward through central Virginia late this evening. If you're headed outdoors this evening, bring rain gear, but there is a good chance that the Nats game will be dry until at least the late innings. The NatCast has been adjusted to reflect the later arrival of precipitation. For the outlook the rest of the week, see Matt's post below.

Monday, April 24, 2006

Drought Busters

The weekend's rain went a long way toward relieving the drought in the Washington DC area. The map of the Maryland/DC/Virginia area, from the National Weather Service's experimental Precipitation Analysis, shows the rainfall for the 24 hours ending at 8am Sunday. There was a wide variation across the area, from the merely generous to the nearly stupendous. Notice the southwest-to-northeast banding structure, with the heaviest amounts both northwest and southeast of the District. As Jason explained earlier, showers and thunderstorms are likely late tomorrow, especially south of the Beltway, but the rest of the week looks quite fine.

Tonight and Tomorrow

Lows tonight under mostly clear skies will be from the low 50s in the city to the upper 40s in the colder 'burbs. Clouds will increase tomorrow afternoon with highs around 71. There is a 60% chance of showers and possibly thunderstorms late tomorrow afternoon through the evening, with higher amounts likely in the southern portion of the region.

Deficit Reduction

The above-average precipitation so far in April has reduced the accumulated yearly deficit from around 40% at the beginning of this month to 24% as of today. The chart shows the official observations at National; weekend rainfall at Dulles was over twice as high. At Dulles, nearly a month's normal rainfall fell in one day, but the total is still well short of the April monthly record of 7.35" set in 1973. chart from NWS data, photo © Kevin Ambrose

Capitol Climate

The American Meteorological Society's Environmental Science Seminar Series on Capitol Hill continues next week on May 3 with the topic, "Changes in Cold Places - A Look at the Greenland Ice Sheet, Arctic Sea Ice and the Antarctic Ice Sheet".

Seasonal Outlook

Latest seasonal forecast: Click here.

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