Superb Solstice, But Some Storms Possible

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

Now

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.

CapitalWeather.com 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

CapitalWeather.com'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.

DC: Drier, Cooler

Now

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.

DC Gets Mugged; Thunderstorms Likely

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

Now

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.

Mediarology

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.

Hot Shot

Now

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.

Mediarology

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.

Junier Conditions on the Way for Father's Day

Now

Cloudy, cool. It's another cloudy and cool afternoon in the Washington DC metro region today as we close out the first half of the month. Temperatures have struggled to get out of the 60s, but by mid afternoon, all reporting locations in the immediate area were at 70° or a little above.

Radar is clear within about a 300 mile range, except for some very isolated showers in extreme southwestern Virginia. The good news is that sunnier, more June-like conditions are expected for the weekend. The bad news is that mugginess will increase also.

Tonight and Tomorrow

Clouds diminishing, warmer. As clouds decrease somewhat tonight, lows will range from the mid 50s ('burbs) to low 60s (urbs) with comfortable humidity. Tomorrow will be mainly sunny with highs near June averages at 80-84°. There is a slight chance of showers or thunderstorms in the afternoon.

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

Still Starving for Moisture

Although this week's rains have helped reduce the moderate drought which was developing in the region through June 9, the 60-day precipitation percentage of normal from NWS (right) shows large deficits through this morning. DC and all adjoining counties are at 75% or less of average, with wide areas at 25-50% (dark orange). Although measurable rain fell the last 3 days, National recorded less than ¼" total. Dulles, on the other hand, had 1.35", but BWI reported 0.12" on Wednesday and only a trace on each of Tuesday and Thursday.

Tropical Topics

A reconnaissance flight was tentatively scheduled today to investigate an area of shower activity over the northwestern Caribbean, but it was canceled because the showers had become less organized than yesterday.

Climate Corner

Last week's SciFri on NPR broadcast live both hours from Alaska on the effect of climate change on the Arctic. Podcasts are available on the web site.

Sit and SpinPesky low pressure to spawn evening storms

** Severe Thunderstorm Watch in Effect Until 9 PM **

Now

Warm, humid, scattered thunderstorms. The persistent low pressure area off the coast that Dan noted earlier today continues to spin counterclockwise, sending a moist flow onto the coastal plain and piedmont of the Northeast and Mid Atlantic regions. The scattered thunderstorms erupting in this flow are once again moving from northeast to southwest across the Washington DC metro region, prompting severe thunderstorm warnings earlier this afternoon for portions of MoCo and Prince George's. Hail up to 1" was reported from the Four Corners and White Oak areas of Silver Spring and NASA in Greenbelt, as well as Herndon, Reston, and Chantilly in Virginia.

A large batch of storms scattered across central and southeastern Pennsylvania is also moving southwest and is likely to affect portions of the metro region in the next couple of hours. The leading group of these storms was already reaching Baltimore City and County by 4:30. Temperatures peaked just over 80° at noon at National, but tumbled to the upper 60s in thundershowers by mid afternoon.

Conditions should be somwhat drier and cooler tomorrow, but temperatures will warm over the weekend.

Pictured: Map of surface pressure (solid lines) and 500 mb height (color shading) this morning over North America and adjacent Atlantic from Unisys. Click here for more explanation.

Tonight and Tomorrow

Scattered showers diminishing, turning cooler. Some scattered showers and thunderstorms may continue through the evening. Otherwise, tonight will be partly cloudy with lows from the low 60s downtown to some upper 50s in the cooler 'burbs. Tomorrow will be mainly cloudy with highs only 69-74°.

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

Tropical Topics: 3-E is History

Depression 3-E in the eastern Pacific has been given last rites. The Atlantic is similarly comatose.

Climate Corner: How Many College Presidents Does It Take to Change a Light Bulb?

Yesterday's WaPo ("Colleges Pledge to Back Climate Initiative") described efforts by 280 college presidents to "raise awareness about global warming and limit their institutions' emissions in moving toward 'climate neutrality'." Local institutions participating include UMD, James Madison, and Howard Community. The subject was also covered by the Baltimore Sun and Chronicle of Higher Education (behind the pay wall).

Great Golfing Day

Now

Sunny, warm. PM Update is blogging today from the beautiful grounds of Woodmont Country Club, where we're providing weather support for the Women's U.S. Open Sectional Qualifier. It's a fine afternoon for golf in the Washington metro area, as temperatures have reached the mid 80s by early afternoon and dewpoints have dropped to the more comfortable low and mid 50s on a northerly breeze around 10 mph. Regional radar around lunch time showed a small, but locally intense, cell southwest of Culpeper moving southeastward, but the immediate metro area has remained clear.

Tonight and Tomorrow

Continued warm, increasing chance of showers. There is a slight chance of isolated showers or thunderstorms through this evening, especially south of the immediate metro area. The rest of tonight will be partly cloudy, continued warm and moderately humid with lows in the upper 60s downtown to near 60° in the cooler 'burbs. Clouds will increase tomorrow afternoon with a 40% chance of showers or thunderstorms late in the day. Highs will be 80-84°.

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

Tropical Topics

The National Hurricane Center began issuing advisories this morning on TD 3-E in the Eastern Pacific. In the Atlantic Basin, tropical cyclone formation is not expected for the next 48 hours.

Climate Corner

The WaPo continued its coverage of Greenland climate changes on Saturday with an article, "In Arctic Ice, Lessons on Effects of Warming", about glacial melting, including the accelerating flow of the Jakobshavn Glacier. For an equal 60 seconds from the (Anti) Competitive Enterpise Institute, click here.