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Posted at 05:00 AM ET, 10/28/2011

Forecast: Colder air is here as wintry weather approaches for Saturday

This post will be updated as necessary during the morning as new information trickles in about the Saturday storm system

10:00 a.m. update: The Winter Storm Watch has been extended into Loudoun county, primarily for elevated areas in the Blue Ridge.

7:00 a.m. update: Overnight models continue to look snowy for outlying western areas, with more rain (potentially a lot of it), potentially mixing with snow late during storm for D.C. and points east. A winter storm watch has been posted for northern Fauquier and Frederick counties (for elevations above 1500 feet), and points north and west (although Loudoun is not in the watch at this time) for the potential of 5” or more of snow. We should emphasize snow amounts (and whether it rains or snows more) look to be highly elevation dependent.We’ll post an accumulation map and more details late this morning.

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

 
I really don't want another heavily-gray day. And temps in the 50s? Boo. +1 for "calm before the storm!"
 
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EXPRESS FORECAST

Today: Mostly cloudy. Late shower? Near 50 to mid-50s. | Tonight: Nippy, rain increasingly likely. Mid-30s to Near 40. | Tomorrow: Rain mixing with and changing to snow, particularly N & W. Some accumulation possible. Near 40. | Sunday: Partly sunny. Near 50 to low 50s. | Get Express Forecast by E-mail

FORECAST IN DETAIL

Some challenges await us as today’s filtered sunshine gets shrouded in increasing cloudcover and temperatures reach the 50s. Tomorrow’s the real tough one: How soon could any snowflakes mix in with our rainfall or even become all snow? We know there’s a storm coming, but the details remain about as uncertain as we see in this range. The odds of accumulating snow in parts of the area (elevated areas to the west and northwest) appear on the way up, at the very least.

Today (Friday): As a piece of our Saturday storm system rolls toward the region, we may eke out some morning sun, but probably clouds win-over the sky. Highs won’t be so high, in the 50-56 degree range. A northerly breeze around 10 mph steadily keeps us chilled, perhaps with a few higher gusts. A few showers (10-20%) are possible by the evening rush hour. Confidence: Medium

Tonight: Rain chances increase as the evening wears on (to about 70% after midnight). Periods of rain may become more persistent toward sunrise, as temperatures bottom in the chilly mid-30s nearer the Blue Ridge, and lower 40s downtown. Confidence: Low-Medium

Keep reading for the forecast through the beginning of next week...

Tomorrow (Saturday): It’s going to be a chilly and wet start to the day with questions quickly turning to snow mixing and perhaps becoming dominant in the area. The changeover is likely to occur over the west and northwest first, maybe sagging southeast through the day. It could be quite the slopfest — anything from moderate rain, to rain and snow mixed, to maybe all snow.

Right now, we think even down into D.C. and southeast the odds are up (about 50%) for a bit of slushy accumulation on grass or elevated objects. Up to a few inches are *possible* in the further north and west suburbs (outside the beltway, places like Sterling, Damascus, Gaithersburg, Clarksburg, Leesburg), with 3”-6” or so a potential outcome once up near the I-81 corridor and west. Whatever falls, it should have plenty of water content. In places that snow accumulates, we might have to worry about tree and power problems if leaves are still plentiful. Temperatures don’t do much during the day, and they may even drop from near 40 if snow works in. Confidence: Low

Tomorrow night: Light snow or light rain and snow mixed should wind down heading through the evening if not prior. It looks like a freeze (the first of the season) is possible for many western suburbs, with temperatures dipping to or below the 32 degree mark. In looking at the potential for clear skies and slowly dying winds, temperatures should fall nicely Lows should range from about the upper 20s to near 30 in the coldest spots to potentially as high as the mid-30s downtown. Bundle up! Confidence: Low-Medium

Sunday: It’s still chilly and wholly autumnal, but at least we should see a greater chance of sunshine. Temperatures, even with substantial sunshine, struggle again, though they should be higher than Saturday thanks to the lack of precipitation. Highs ranging from near 50 to the mid-50s should work, though Saturday’s potential snow may lead to cooler temperatures in spots. The bright spot for all of us may be lighter winds than Saturday. Confidence: Medium

A LOOK AHEAD

Sunday night: We’re still cold with a few isolated spots perhaps nearing freezing conditions again. Lows for the region should generally range in the mid-to-upper 30s (downtown DC seeing the warmest readings nearer 40). As far as sky conditions go, stars could be blocked by some passing clouds. Confidence: Low-Medium

Halloween looks so-so with sun battling the clouds for dominance. A sprinkle or short period of drizzle can’t be ruled out. Highs stay chilly in the mid-50s or perhaps a bit warmer. So, especially in the evening with kids in costumes, make sure to dress in layers as temperatures fall back into the 40s pretty quick after dark. Confidence: Low-Medium

On Tuesday we spend the day with many clouds overhead and temperatures in the mid-to-upper 50s. So far there is no major threat of rain, but we’ll keep you updated if we deem new information indicates any notable change! Thinking positive to close: If we see a few breaks in the clouds, I suppose… we could hit 60 in a few spots? Confidence: Low

By  |  05:00 AM ET, 10/28/2011

Categories:  Forecasts

 
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