Saturday, December 29, 2007
Saturday Sunshine, then a Sunday Slip Fest?
Jason Samenow @ 12:00 AM
Clouds and showers will quickly move out early this morning, clearing the way for a mainly sunny Saturday. But as quickly as it cleared today, it will cloud over Sunday, with the potential for a messy, miserable mix of precipitation.
Becoming mostly sunny and mild, low to mid 50s.. The sun should be shining by the time most of us have awakened. The sunshine will warm us up nicely, despite the passage of a cold front pre-dawn. Accompanied by a 10-15mph northwest breeze, we'll warm into the low 50s, not realizing the understated arrival of cooler air until the evening. Overnight, it will be on the chilly side with clear skies gradually becoming mostly cloudy towards morning. Low temperatures should range from 28-32 (suburbs-city).
Winter berries enjoy partial sunshine along Wisconsin Avenue in NW, DC on Thursday. By CapitalWeather.com photographer Ian Livingston.
Wintry mix developing. Light mixed precipitation will likely move in from the south in the late morning to early afternoon hours. A steady mix of rain and sleet is likely in DC and points south and east throughout the afternoon, with sleet and snow more likely north and west of DC. As usual, the rain-snow line will be somewhere in the metro area or just to the west. High temperatures should range from the mid 30s north and west of town to the upper 30s in town and to the south and east.
Overnight, the wintry mix is likely to change to snow north and west of DC where a light accumulation is possible. In town and points south and east, rain and sleet may briefly change to snow before ending, with little accumulation. Lows should range from 29-34 (northwest-southeast).
This is a complicated situation, and these details are subject to change. For more discussion, see the Snow Lover's Crystal Ball below.
Behind Sunday's storm, Monday will be dry and seasonable, with highs in the 40s. After a powerful cold front passes through the region early Tuesday, temperatures will start dropping. By Wednesday and Thursday, high temperatures will likely be locked up in the low to mid 30s.
Snow Lover's Crystal Ball 
Next Chance of Accumulating Snow:
Sunday, December 30-Monday, December 31
Probability: 30%
Potential Impact:
Commentary: A wave of low pressure will develop along a stalled front over the southeast into the Mid-Atlantic. This low will move northeastward Sunday along the front, with mixed precipitation developing mid-day and continuing into the very early morning hours Monday.
Current forecast models suggest the low will track to our east which is usually favorable for snow or frozen precipitation. That's because an easterly track means our winds will be northerly and will draw in and sustain cold air. The problem is that the supply of cold air is to the north is pretty lacking.
When the precipitation moves in during the day Sunday, temperatures will above freezing in most spots, so travel problems and accumulation are not likely -- even north and west. Precipitation will probably be a mix of rain, sleet and snow with more rain in DC and south and east, and more sleet and/or snow north and west of town.
After dark, things could get a bit more interesting as precipitation increases in intensity, temperatures drop and rain/sleet changes to snow. As usual, the colder spots to the north and west stand the best chance of seeing measurable frozen precipitation.
Based on current information, the immediate metro area probably has about a 1/3 or 1/4 chance of seeing some accumulation Sunday night, with the north and west suburbs having as high as a 50/50 shot. Stay tuned for further updates.
Today
Becoming mostly sunny and mild, low to mid 50s.. The sun should be shining by the time most of us have awakened. The sunshine will warm us up nicely, despite the passage of a cold front pre-dawn. Accompanied by a 10-15mph northwest breeze, we'll warm into the low 50s, not realizing the understated arrival of cooler air until the evening. Overnight, it will be on the chilly side with clear skies gradually becoming mostly cloudy towards morning. Low temperatures should range from 28-32 (suburbs-city).Winter berries enjoy partial sunshine along Wisconsin Avenue in NW, DC on Thursday. By CapitalWeather.com photographer Ian Livingston.
Sunday
Wintry mix developing. Light mixed precipitation will likely move in from the south in the late morning to early afternoon hours. A steady mix of rain and sleet is likely in DC and points south and east throughout the afternoon, with sleet and snow more likely north and west of DC. As usual, the rain-snow line will be somewhere in the metro area or just to the west. High temperatures should range from the mid 30s north and west of town to the upper 30s in town and to the south and east.Overnight, the wintry mix is likely to change to snow north and west of DC where a light accumulation is possible. In town and points south and east, rain and sleet may briefly change to snow before ending, with little accumulation. Lows should range from 29-34 (northwest-southeast).
This is a complicated situation, and these details are subject to change. For more discussion, see the Snow Lover's Crystal Ball below.
A Look Ahead: Cold Spell Mid-week
Behind Sunday's storm, Monday will be dry and seasonable, with highs in the 40s. After a powerful cold front passes through the region early Tuesday, temperatures will start dropping. By Wednesday and Thursday, high temperatures will likely be locked up in the low to mid 30s.
Next Chance of Accumulating Snow:
Sunday, December 30-Monday, December 31
Probability: 30%
Potential Impact:
Commentary: A wave of low pressure will develop along a stalled front over the southeast into the Mid-Atlantic. This low will move northeastward Sunday along the front, with mixed precipitation developing mid-day and continuing into the very early morning hours Monday.
Current forecast models suggest the low will track to our east which is usually favorable for snow or frozen precipitation. That's because an easterly track means our winds will be northerly and will draw in and sustain cold air. The problem is that the supply of cold air is to the north is pretty lacking.
When the precipitation moves in during the day Sunday, temperatures will above freezing in most spots, so travel problems and accumulation are not likely -- even north and west. Precipitation will probably be a mix of rain, sleet and snow with more rain in DC and south and east, and more sleet and/or snow north and west of town. After dark, things could get a bit more interesting as precipitation increases in intensity, temperatures drop and rain/sleet changes to snow. As usual, the colder spots to the north and west stand the best chance of seeing measurable frozen precipitation.
Based on current information, the immediate metro area probably has about a 1/3 or 1/4 chance of seeing some accumulation Sunday night, with the north and west suburbs having as high as a 50/50 shot. Stay tuned for further updates.
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