Friday, July 21, 2006

Showers Possible, More Likely Tomorrow


Scattered thunderstorms were breaking out late this afternoon south of the Beltway along I-95 and more widespread southwest of Culpeper toward Charlottesville. These were mostly moving eastward. Temperatures which had stayed mainly in the upper 80s popped up to 92° at National Airport with the switch to a more favorable west wind at 3pm.

Tonight and Tomorrow

There is a 50% chance of scattered showers and thunderstorms through this evening. The most likely targets are the areas south and west of the District. Lows tonight under hazy skies will be from the upper 70s downtown to the low 70s in the 'burbs. Tomorrow will again be muggy but with less sun than today in most places and highs in the mid 80s. The chance of mainly afternoon thundershowers, some possibly severe, is 60%.

For the outlook through the rest of the weekend, see Camden's post below.

Tropical Topics

After making landfall early this morning at Nantucket, Beryl lost its tropical characteristics as it headed northeastward to Nova Scotia. The last tropical advisory on the storm was issued at 11am. (Just for the record, the official pronunciation is either "Burl" or "Ber-il".)

Thursday, July 20, 2006

Warm and Humid; Beryl Brushing By Beantown


Warm and humid conditions prevail throughout the Washington metro area this afternoon. Temperatures at mid afternoon were in the upper 80s to 90° and dewpoints were mainly in the low 70s. National Airport claimed to have light rain at 3pm, but it was virtually undetectable on radar.

Tonight and Tomorrow

Warm and humid: Tonight will be warm and humid, with a slight chance of a passing shower or thunderstorm through this evening and lows in the mid 70s. Tomorrow will be (wait for it . . . ) warm and humid! (Hey, it's July in DC, folks.) Highs should be close to where they were today; that means right 'round the upper 80s in most parts. The chance of thunderstorms is 40%.

For the chances of improvement in the short and medium range, see Larson's Long-Range below.

Tropical Topics

Tropical Storm Beryl is moving toward the northeast with maximum winds of 50 mph (down from 60) late this afternoon; some further weakening is expected. At 5pm it was about 150 miles southwest of Nantucket on a track which is likely to just brush the southeastern coast of Massachusetts. Radar shows some showers over central and eastern Long Island and the outer portion of Cape Cod.

Non-stop breathless coverage of this relatively minor event from Cantore & Co., complete with tourists on cellphones waving in the background, is predicted for TWC.


Most sane people will find this very hard to believe, but there are some otherwise normal-looking residents of the DC area who actually dislike air conditioning. The WaPo profiles this phenomenon in today's Home section.

Britain Bacon

The Guardian newspaper reports that Britain was "bacon" along with much of Europe under record heat yesterday. The reading of 36.3° C (97.3° F) at Charlwood (near Gatwick) broke the national all-time July record of 36° C set in 1911. The new record was in turn surpassed by 97.7° F at Wisley in Surrey.

Photo of a pedigree Berkshire pig keeping cool in Worcester, England, from Guardian Unlimited.

Tuesday, July 18, 2006

Scorching Heat Could Give Way to Severe Storms

A Severe Thunderstorm Watch is in effect for the Washington area until 10pm. The Heat Advisory remains in place through 8pm. Detailed watches and warnings by county are available above.


Although no records are at risk of being broken, the Washington metro area is sweltering this afternoon under heat indexes exceeding 100 at nearly all locations. The official reading reached 97° shortly before 2pm, but a southerly river breeze knocked that back down to 94° by 3pm and another degree lower the following hour.

Shortly after 4pm, a line of thunderstorms extended southwestward from near the intersection of I-66 and I-81 in Virginia. It was expanding and moving slowly eastward.

Tonight and Tomorrow

There is a chance of thunderstorms, some possibly severe, through this evening, especially in the western and southern suburbs. Lows tonight will be in the mid to upper 70s. Tomorrow will continue to be humid, but with high temperatures near 90.

For the outlook through the rest of the week, see Jason's post below.

As Matt noted earlier, the DC area has certainly seen more extreme heat waves. What is remarkable about the current heat, however, is the breadth of its coverage across the country. The four shades of purple in the maximum temperature map for yesterday represent 5-degree intervals from 90° up to 110°. These extend literally from coast to coast. Although the smoothing in the plot doesn't show all of the detail, the individual high temperatures confirm that every one of the 48 contiguous states reported a temperature of at least 90°.

Maximum daily temperature chart at 8pm yesterday from Unisys.

Tropical Topics

Tropical Depression 2 formed this morning, and a Tropical Storm Watch has been issued for the North Carolina coast, including most of the Outer Banks. As of the 5pm Advisory, the system was very close to tropical storm strength. The depression is moving slowly toward the north with a more northwesterly track expected along with further intensification.

Monday, July 17, 2006

Hot Town, Summer in the City


Heat advisories are in effect through this evening and again tomorrow afternoon and evening. Temperatures were well into the mid 90s by mid afternoon today in the Washington metro area. The most common reading was 95° at 3pm. At 4pm, National Airport was 96° (back to 93° at 5pm), and BWI reported 97&deg. Fortunately, the subsiding air under a dome of high pressure which was producing the heat was also limiting dewpoints to the upper 60s and low 70s.

Tonight and Tomorrow

Hot! Tonight will be mainly clear and very warm with lows in the upper 70s, a bit cooler in the less-paved areas. Tomorrow will be continued hot and a little more humid with highs in upper 90s to near 100 and a slight chance of an afternoon or evening thunderstorm.

For the extended outlook through the rest of the week, see Jason's post below.

The core of today's heat is focused in the southern Plains, where readings over 100° are common from Kansas southward through Oklahoma to northern Texas. Temperatures over 90° (purple shading) covered most of the East Coast, reaching well into western New England.

Temperature chart at 4pm today from Unisys.

Tropical Topics

An area of storms hanging around a couple of hundred miles off the Carolina coast is starting to show some potential to become tropically depressed. A reconnaissance flight is scheduled for tomorrow to investigate the situation.

Climate Corner

The Discovery Channel, which happens to be based in Silver Spring, premiered a 2-hour documentary last night on global warming. The program, which was jointly produced by NBC News and the BBC for Discovery, was hosted by Tom Brokaw. Besides being a well-presented and comprehensive view of the subject, the show refreshingly interviewed only scientists directly involved in the area, rather than pretending to present a "balanced" mix of pundits, politicians, and lobbyists. Naturally, the right-wing noise machine wasted no time in spewing out personal attacks on the messengers (especially Brokaw, whose name appears in nearly every paragraph of the taxpayer-funded propaganda issued from the committee run by the Senator from Oilahama. Of course, what can you expect from public "servants" who have not the slightest clue about the Internet, let alone anything scientific?). The program is scheduled to be re-broadcast Saturday at 8pm.

Seasonal Outlook

Latest seasonal forecast: Click here.

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