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Posted at 06:50 PM ET, 08/14/2011

Flash flooding possible, especially northern suburbs

Flash Flood Watch through evening

11 p.m. update: Storms are now mainly east of I-95 and will head through P.G. County and toward the Chesapeake Bay over the next hour or so. Radar-estimated rainfall indicates 2-3”+ has fallen in some areas north of the District. A Flash Flood Warning remains in effect until 12:30 a.m. in southeast Montgomery and northwest P.G. counties, with another Flash Flood Warning until 1 a.m. from northern Montgomery into southern Frederick counties. With a water rescue already having occurred in the District, it’s important to remember not to drive across a flooded roadway.

We get a break behind this current line of storms, but a few more are possible overnight and tomorrow as well.

9:30 p.m. update: Northern suburbs (eastsern Loudoun, southern Frederick, Montgomery and northern P.G. counties) have seen heavy rain with as much as 2”+ the past couple of hours. In southeast Montgomery and north/central P.G. counties, a Flash Flood Warning is in effect until 12:30 a.m. DON’T drive across a flooded road! In the District, along much of I-66 to the west and Rt 50 to the east, and in the southern suburbs radar has been much quieter until you get down to southern Fauquier, Stafford and southern Charles counties.

6:50 p.m. update: Finally, the D.C. area may get in on some rain, as an area of showers and storms now moving into the far western suburbs (Loudoun & Fauquier counties) looks to track east across the region over the next few hours. The heaviest activity is trying to split both south and north of the District and close-in suburbs, but still anyone is at risk for a period of heavy rain and gusty winds.

See end of post for earlier updates...

From 5 a.m...

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

 
Sure, we could use the rain, but does it have to come on the weekend?
 
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EXPRESS FORECAST

Today: Numerous showers and storms. Near 80. | Tonight: 60% chance of evening showers. Upper 60s to low 70s. | Tomorrow: 40-50% chance of showers. Low-to-mid 80s. | A Look Ahead | Get Express Forecast by E-mail

FORECAST IN DETAIL

Much of the area receives a good dose of the wet stuff for the second straight day today (yesterday’s totals were generally .25”-0.5” with some locally heavier amounts). While the weekend timing isn’t ideal, our parched ground is eager to accept the rain whenever it can get it. Even though the area is in what’s considered a moderate drought, some localized flooding is possible today where heavy downpours occur. Conditions gradually improve as we head into the work week.

Today (Sunday): Waves of showers - some possibly with thunder and gusty winds - are in the forecast today. Many spots could see rain totals near or upward of a half-inch, with near or over 1” possible where locally heavy downpours occur. The National Weather Service cautions that areas that see repeated storms could see 3-6”, which has prompted a Flash Flood Watch. We’ll probably see occasional breaks from the rain, but even then skies likely remain mostly cloudy to overcast, helping to keep highs in check - near 80 with high humidity and breezes from the south. Confidence: Medium

Tonight: Occasional showers remain a decent bet this evening (60% chance) as a low-pressure center tracks nearby, before the rain risk decreases overnight. Generally not the most pleasant night to be out and about with the shower potential, muggy air, and some fog/mist possible as well. Overnight lows don’t drop too much, only to the upper 60s to low 70s. Confidence: Medium-High

Keep reading for the forecast through midweek...

Tomorrow (Monday): Our prospects for showers are still pretty good to begin the work week, though they should be lighter and less numerous than today. We’ll be on the back side of a cold front, but an upper-level impulse threatens a 40-50% chance of showers, maybe with an isolated thunderstorm mixed in during the afternoon. Skies are mostly cloudy and afternoon highs are a little warmer, in the low-to-mid 80s. Confidence: Medium-High

Tomorrow night: Rain chances wind down as we head through the night, though a couple evening showers are still possible. Skies begin to slowly clear overnight, and breezes from the west/northwest dry us out as lows reach the mid-to-upper 60s. Confidence: High

A LOOK AHEAD

Tuesday and Wednesday are shaping up to be rather nice for mid-August around here, though an isolated shower or storm can’t be ruled out on Tuesday. Humidity shouldn’t be terribly high and mid-to-upper 80s ain’t half bad with partly to mostly sunny skies. Confidence: Medium

Earlier updates...

5:25 p.m. update: Showers/storm activity has diminished and, outside an a pop shower or two, we should get another break for the next couple hours. However, a large area of showers and storms to the west and southwest may move into region after 7 or 8 p.m. We’ll keep an eye on it.

3:50 p.m. update: Widely scattered showers and thundershowers are beginning to develop and should gradually become more numerous. Still - they will tend to be hit or miss. An isolated severe storm with strong winds is possible - but heavy downpours will be the main impact with this activity.

1:20 p.m. update: Most of the area is enjoying a nice break from rain. However, partial sunshine is destabilizing the atmosphere for possible storms later today. The Storm Prediction Center indicates a slight risk of severe thunderstorms this afternoon. Any storms that develop are likely to produce very heavy rain along with the small possibility of damaging winds, hail, and an isolated tornado. The most likely timing will be between 4 and 8 p.m.

By  |  06:50 PM ET, 08/14/2011

Categories:  Forecasts

 
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