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Posted at 05:00 AM ET, 03/23/2011

Forecast: Topsy-turvy March threatens t’storms today... weekend snow?

9:45 a.m. Update: After some early-morning showers, radar is quiet for the time being. Looks like we’ll stay that way, save for an isolated light shower or two, through morning and maybe into early afternoon. The best chance for showers and thunderstorms appears to be mid-afternoon into evening. As mentioned below, some storms could be strong, and with that in mind the Storm Prediction Center has placed the area under a slight risk for severe storms that could produce damaging winds and large hail.

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

 
50s and 60s are decent enough to enjoy periods between showers and storms.
 
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EXPRESS FORECAST

Today: Partly to mostly cloudy. Occasional showers & possible t’storms. Mid-50s to mid-60s (north to south). | Tonight: 60% chance of evening showers/storms. Upper 30s to mid-40s. | Tomorrow: Breezy, 30% chance of a.m. showers, p.m. clearing. Upper 40s to low 50s. | A Look Ahead | Get Express Forecast by E-mail

FORECAST IN DETAIL

Talk about a tricky forecast. Today we’ve got high temperatures that are likely to span some 20 degrees across the region (from near 50 to the north to near 70 to the south) plus the potential for some strong thunderstorms. Tomorrow’s colder with a small chance of conversational snowflakes mainly north and west of town. And a cold weekend brings a better, but nowhere near certain, chance of wintry precipitation. March weather is most certainly living up to its topsy-turvy reputation.

Snow Potential Index: 2 (↑) - Would ya look at this. SPI creeps up ahead of weekend snow chance (& another chance around Tues. next week?). Hard to get accumulation in late March but it can happen.
 
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
 


Radar & lightning: Latest regional radar shows movement of precipitation and lightning strikes over past two hours. Refresh page to update. Click here or on image to enlarge. Or see radar bigger on our Weather Wall.

Today (Wednesday): A warm front in the vicinity means partly to mostly cloudy skies (intervals of sun are more likely around D.C. and to the south than to the north), occasional showers (more rain north, less rain south), and a chance of thunderstorms. Some storms could be strong like Monday’s, with heavy rain, gusty winds, small hail and lightning. Temperatures are tricky, likely spanning a wide range over a relatively short distance. Highs probably range from the low 50s to near 50 to the north from around northern Montgomery County toward the MD/PA border, to near 70 to the south and southwest around Fredericksburg and Culpeper. In the greater metro area, mid-50s to mid-60s (from north to south) looks to be the range. Confidence: Low-Medium

Thundercast:
Probability: Morning: 20%; Afternoon/Evening: 50%
Coverage: Morning: Isolated-Scattered; Afternoon/Evening: Scattered-Widespread


Tonight: Showers and storms may (60% chance) extend into the evening - any storms could be strong as described above - but should diminish later in the evening or overnight as colder air works in from the northwest behind a cold front passing by. Could even see a few non-accumulating snowflakes or sleet pellets north and west of D.C. if any precipitation lingers late enough into the overnight. Rain totals for the day and night shoot for the 0.25”-0.75” range (best chance for higher end of range is north of D.C.), with locally higher totals possible especially in areas that see t’storms. Lows by morning drop to the upper 30s to mid-40s (coldest north & west, warmest south & east). Confidence: Low-Medium

Keep reading for the forecast through the weekend...

Tomorrow (Thursday): An upper-level disturbance trailing behind the overnight cold front means clouds may be slow to clear during the morning. A few morning showers are possible as well (30% chance), and can’t rule out some non-accumulating snowflakes in the north and west suburbs. Otherwise, it’s a cool and breezy day with clearing skies by or during the afternoon, highs in the upper 40s to low 50s, and winds from the northwest around 15-25 mph with gusts to near 35 mph. Confidence: Medium

Tomorrow night: Winds diminish and it’s rather chilly under clear and starry skies. Lows sink to the mid-20s in the coolest suburbs to the low 30s downtown. Check the blog tomorrow for our gardening expert’s advice on how to protect sensitive plants and flowers. Confidence: Medium-High

A LOOK AHEAD

Skies should be at least party sunny on Friday, and any clouds are probably high ones that would filter the sun more so than block it. Even with the sun, though, a chilly wake-up and an overall cool air mass limits afternoon highs to the upper 40s to low 50s. We may still have somewhat of a breeze but it’s likely lighter than Thursday. Clouds increase Friday night as our next weather-maker gets closer from the west and overnight lows bottom in the upper 20s to mid-30s. Confidence: Medium

Highs only in the 40s to near 40 aren’t the only thing potentially wintry this weekend. A slight chance of rain, sleet and/or snow on Saturday turns into a 50/50 chance or better Saturday night into Sunday. In late March, the odds are usually stacked against accumulating snow and/or sleet, and the overall pattern for this weekend is one that we might even have trouble getting accumulation from in the heart of winter. That said, accumulating snow and/or sleet can’t be ruled out, mainly Saturday night into Sunday morning when lows could go as low as the upper 20s to low 30s. There’s also a chance the precipitation tries to scoot by south of the area. Confidence: Low

By  |  05:00 AM ET, 03/23/2011

Categories:  Forecasts

 
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