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Posted at 05:00 AM ET, 07/30/2011

Forecast: No end in sight to 90+ heat

New, interactive: CWG intern Justin Grieser checks who/what was hottest in D.C. on hottest day in 14 years yesterday: Quiz | Gallery

Code Orange air quality today: unhealthy for sensitive groups

Today's Daily Digit
 
A somewhat subjective rating of the
day's weather, on a scale of 0 to 10.

 
Amazing: Around 10 degrees cooler than Friday only gets us down to the mid-90s. At least the heat index isn't off the charts like last heat wave.
 
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EXPRESS FORECAST

Today: Partly to mostly sunny. Slight p.m. t’storm chance. Mid-90s. | Tonight: Slight t’storm chance early. Upper 60s to upper 70s. | Tomorrow: Partly to mostly sunny. Slight p.m. t’storm chance. Low-to-mid 90s. | A Look Ahead | Get Express Forecast by E-mail

FORECAST IN DETAIL

After yesterday’s record-smasher, today’s high-temperature records (99 at National, 98 at Dulles, 98 at BWI) are probably safe, though I do emphasize probably given our proclivity for tying or breaking records this summer. Record or not, the generally hot and humid streak goes on with no end in sight. In fact, we’re coming up on two weeks straight of 90 or better at Reagan National. The all-time record 90+ streak is 21 days (occurring in both 1980 and 1988; h/t CWG’s Ian Livingston), and while it’s very far from a sure bet, I do think we have a fighting chance of reaching or passing that mark.

Temperatures: Latest D.C. area temperature map powered by iMapWeather (base map by Google). Click and hold on map to pan. Double-click to zoom. Refresh page to update. See larger map on our Weather Wall.

Today (Saturday): Relative to yesterday, there’s definitely a glass-half-full way to look at today’s partly to mostly sunny skies and hot highs in the mid-90s - that’s several degrees cooler than Friday, and a drying breeze from the northwest should gradually push humidity down toward the moderate range, though the heat index still gets to near 100. There is a slight chance of a late afternoon or evening t’storm, mainly west and south of the District. But most activity should stay west and south of the metro area. Confidence: Medium-High

Tonight: That slight chance of a storm remains, mainly south of the District. But again, most of the action probably stays south of the metro area. Beneath partly to mostly clear skies, overnight lows range from the upper 60s in the coolest north and west suburbs, to the mid-to-upper 70s downtown. Confidence: Medium-High

Keep reading for the forecast through midweek...

Tomorrow (Sunday): Kind of a run-of-the-mill late-July Sunday, at least as far as this July is concerned, on track to become the hottest month ever in D.C. We're partly to mostly sunny, still hot and fairly humid with highs in the low-to-mid 90s and a slight chance of a late afternoon or evening storm. This would be the 14th straight day with a high at or above 90 at Reagan National. Confidence: Medium-High

Tomorrow night: Just to be sure, I’ll keep mention of a slight t’storm chance during the evening. Otherwise, we’re looking at partly to mostly clear skies and lows in the upper 60s to low 70s (suburbs) to the mid-to-upper 70s (downtown), as a light breeze from the south keeps us on the muggy side. Confidence: Medium-High

A LOOK AHEAD

More of the same expected Monday through Wednesday - partly to mostly sunny, moderate to high humidity, and highs in the low-to-mid 90s. Storm chances don’t appear all that high, around or below 20% each day. Confidence: Medium-High

Wednesday would be our 17th straight day at or above 90 at National if all goes as planned. That means if the 90+ heat continues uninterrupted - and models suggest it very well may, but of course uncertainty always increases in the long range - then we’d tie the all-time record 90+ streak of 21 days on Sunday (Aug. 7) and break it on Monday (Aug. 8).

By  |  05:00 AM ET, 07/30/2011

Categories:  Forecasts

 
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