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Posted at 05:00 AM ET, 03/09/2011

Forecast: Here comes more heavy rain

Rainfall through Thurs. night could total 1.5-3"

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

 
A cloudy, cool day with more rain on the way.
 
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EXPRESS FORECAST

Today: Cloudy. 40-50% chance of showers arrives from west to east. Mid-40s to near 50. | Tonight: Rain becomes steadier, heavier. Low 40s to near 40. | Tomorrow: Breezy with rain, heavy at times. Mid-50s to near 60. | A Look Ahead | Get Express Forecast by E-mail

FORECAST IN DETAIL

Another significant rain event is on the way, with the potential for as much or more rain than this past weekend’s generally 1-2.5” soaking. The culprit is a system similar to the the weekend’s - a cold front with an area of low pressure along it - that brings a chance of showers today and the likelihood of moderate to heavy rain late tonight and tomorrow. Some might see a smidge of snow and/or sleet at the storm’s beginning and/or end, but the real concern is the chance of minor to moderate flooding issues late tonight and tomorrow.

Snow Potential Index: 1 (↑) - Any flakes Thurs. night shouldn't accumulate. Slight snow chance early next week, wouldn't put much stock in it yet.
 
The SPI is a daily assessment of the potential for accumulating snow for the next week on a 0-10 scale. Get the 'SPI' on Twitter
 

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 (Wednesday): Cloudy skies and onshore breezes, around 10-15 mph from the east/southeast, keep temperatures in check today with highs in the mid-40s to near 50. The western suburbs stand a 40-50% chance of showers as early as mid-to-late morning (there could even be a few pings of sleet if precipitation arrives early enough), then that 40-50% chance of showers advances to D.C. and east during the late morning or afternoon. Confidence: Medium

Tonight: A Flood Watch goes into effect this evening as steadier rain moves in from the southwest. The rain could be moderate to heavy at times overnight, with temperatures edging back to lows in the low 40s to near 40. Confidence: Medium

Keep reading for the forecast through the weekend...

Tomorrow (Thursday): Rain continues through much or all of the daylight hours, and it could be moderate to heavy at times. Watch for flooding on those same roads and low-lying areas that experienced flooding on Sunday. Winds from the southeast around 15-25 mph with higher gusts push highs to the mid-50s to near 60, before they shift to come out of the west and northwest during the afternoon into evening as temperatures fall through the 50s to near 50 or into the 40s. Confidence: Medium

Tomorrow night: Rain should lighten during the evening and may come to an end by around midnight. However, a trailing area of low pressure in the upper atmosphere could keep the rain going longer or bring the return of some light rain toward dawn, especially west of D.C. where it might be cold enough for any rain to mix with or change to snow and/or sleet. Any accumulations more than a dusting or so are probably confined to west of Loudoun and Fauquier counties. Confidence: Medium

A LOOK AHEAD

Depending on the location and strength of the upper-level low, a chance of light rain may linger into Friday morning. The best chance of this would be from around D.C. and to the west. Any early-morning rain could mix with or change to snow and/or sleet mainly west of D.C. Again, this would be mainly non-accumulating except possibly west of Loudoun and Fauquier counties. Otherwise, we’re looking at a breezy and colder day with highs in the upper 40s to low 50s under partly sunny to mostly cloudy skies. Lows Friday night fall back to near 30 to the mid-30s. Confidence: Medium

The weekend looks at least partly sunny and generally pleasant with highs in the mid-50s to near 60 on Saturday and 50s on Sunday. Can’t rule out a passing shower Saturday afternoon or night with Saturday night lows in the upper 30s to mid-40s. Confidence: Medium

By  |  05:00 AM ET, 03/09/2011

Categories:  Forecasts

 
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