Thursday, June 21, 2007

Superb Solstice, But Some Storms Possible

** Severe Thunderstorm Watch in Effect Until 10 PM **


Mostly sunny, warm. Clouds drifting southward this afternoon from some fairly heavy thunderstorm activity in Pennsylvania ahead of a cold front have marred what was otherwise a crystal-clear blue sky in the Washington metro area. In fact, these storms, which have already prompted a severe thunderstorm warning for Washington County, MD, appear to have the momentum to at least graze the northern suburbs by evening.

Otherwise, mid afternoon temperatures in the range of 86-88° and dewpoints as low as 50° have combined for a very comfortable summer solstice. chart from NWS data, photo © Kevin Ambrose

Tonight and Tomorrow

Chance of evening storms, but mainly comfortable. There is a chance of showers or thunderstorms through this evening, especially north of the Beltway. The remainder of tonight will be partly cloudy with comfortable humidity and lows in the low to mid 60s in the city and some upper 50s in the 'burbs. Tomorrow will be sunny, dry, and a little cooler with highs 81-84°.

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

Blogrolling's Andrew Freedman had a post on Monday at The Weather Channel's Forecast Earth blog reviewing temperature and precipitation anomalies (departures from average) through May of this year.

Wednesday, June 20, 2007

DC: Drier, Cooler


Sunny, cooler, less humid. The cold front which passed through in the early morning hours has brought with it sunny, cooler, and less humid conditions for the Washington metro area this afternoon. Temperatures at mid afternoon were generally in the low to mid 80s, dewpoints were in the much more comfortable 50s, and a refreshing northwesterly breeze was gusting to 25 mph at times.

Yes, we did have thunderstorms in the area. National Airport reported thunder or light rain in 8 separate hourly observations overnight, but the grand total of precipitation was only the minimum amount to verify a rain forecast, 0.01". Dulles didn't fare much better with a mere 0.04", and BWI had only 0.17".

Tonight and Tomorrow

Open the windows! Mostly clear and cooler conditions with comfortable humidity will prevail overnight; lows will range from the low 60s in the city to the low 50s in the outlying areas. Tomorrow will be sunny and seasonably warm with low humidity and highs 83-88°.

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

Climate Corner/Book Nook

The latest post over where the Real Climatologists hang out is an extensive review of a new book by Chris Mooney coming out in a couple of weeks (July 9), "Storm World". The book tackles one of the most controversial subjects related to climate change, the relationship between global warming and hurricanes. Despite Mooney's previous politically-oriented book, the Real folks say that this is "a thoughtful, non-partisan, and scientifically and historically accurate review of the emergent science." To meet the author, mark the date of July 21, when the Storm World tour arrives at Politics and Prose right here in Spin City.

The book is scheduled to be featured in the July issue of Wired magazine. It was also mentioned briefly in the recent summer reading roundup of the BoGlo.

Tuesday, June 19, 2007

DC Gets Mugged; Thunderstorms Likely

** Severe Thunderstorm Watch in Effect Until 11 PM **


Hot, very humid. OK, it's official, you can start complaining now. With dewpoints in the oppressive 70s, temperatures in the 90s are feeling very uncomfortable in the Washington metro area this afternoon. One of the worst reports in the greater metro region was at 2pm from Fredericksburg, where a dewpoint of 75° combined with an air temperature of 95° to yield a heat index of 107.

A line of thunderstorms forming by mid afternoon in the usual location, just west of I-81, was moving generally northeastward, but it could reach at least the far western suburbs by early evening. A couple of small popup storms were also developing to the east, including one in the far western corner of Montgomery County which has produced some distant rumbles of thunder here at Update Central.

Tonight and Tomorrow

Muggy, thunderstorms likely, then cooler, less humid. The chance of thunderstorms will continue through this evening, especially to the west of the immediate metro area. Lows will be in the low 70s downtown to the upper 60s in the cooler 'burbs. Some clouds and possibly some lingering showers in the morning tomorrow will give way to sunshine in the afternoon and much more pleasant conditions. Highs of 84-87° will be accompanied by much lower humidity.

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


Today's WaPo salutes the approaching solstice with the return of its series, "Secret Worlds of Summer", in the Metro section. The first installment, "Mysteries of Light", surveys the role of the sun in myth and in local scientific investigations at NIST in Gaithersburg and NASA in Greenbelt.

Monday, June 18, 2007

Hot Shot


Hot, humid. It's a two-fer in the Washington metro area today as the proverbial mercury reached 90° for the second day in a row by early this afternoon, hitting at least 94° at both National and Dulles. At Dulles, this ties the record for the date set just last year. This is the first time this season we've had consecutive 90° days. From the sun-drenched patio of Update Central here in west-central MoCo, the remote readout is a bit too enthusiastic in displaying triple digits, but the official reporting stations at Culpeper and Frederick registered 97°.

Humidity, while not oppressive, is somewhat more noticeable than yesterday with dewpoints rising from the mid 50s to the low and mid 60s (afternoon relative humidity around 35%). Some scattered thunderstorms have popped up near Winchester and also further south towards Charlottesville.

Hot and muggy conditions will prevail through tomorrow as a nearly-stationary cold front lurks around the "back door" (along the Mason-Dixon line). Cooler temperatures will await the arrival of a cold front from the west on Wednesday.

Tonight and Tomorrow

Muggy. There is a slight chance of widely scattered thunderstorms through this evening, especially to the west. It will be warm and muggy tonight with lows in the low 70s downtown to some upper 60s in the 'burbs. Tomorrow will be hot and humid with a 30% chance of thunderstorms late in the day or at night and highs 91-96°.

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


Congratulations to WTTG Channel 5's Sue Palka, who won the local Emmy award on Saturday for best weathercaster. This is the second time in recent years that Sue has collected the trophy. She also won in 2005. Among its total of 16 Emmys, the station also won the spot news award for coverage of tropical storm Ernesto.

Climate Corner

Despite some teething troubles, the authoritative British journal "Nature" has formally launched its "Nature Reports Climate Change", including sections for latest news and blogs. An introduction to Vol. 1 calls for "An end to hot air" on the subject.

Seasonal Outlook

Latest seasonal forecast: Click here.

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