Thursday, February 01, 2007
Winter Weather on Its Way?
Light Accumulations Possible
Josh Larson @ 1:20 PM
*Winter Weather Advisory in Effect 6pm today through 9am Friday*
A fast moving and fickle winter storm arrives today with scattered flurries during the daylight hours; evening rush should be fine in almost all areas. More in the way of precipitation (from a second area of low pressure) is possible tonight. The CapitalWeather.com team believes that up to an inch of snow could fall before a changeover to sleet and freezing rain (or even plain rain in spots) overnight.
Where will the heaviest precipitation fall? The heaviest precipitation will likely be south of Washington, DC. Note, however, that the further east you go from DC, the more mixing in there will be of ice and rain.
When will the snow start? Scattered flurries are possible during the daylight hours today; however, it looks like the heaviest precipitation will hold off until this evening and the overnight hours. See detailed timeline above.
Where is the precipitation now? Click here for the latest radar loop. Note that parts of the leading edge of the precipitation may be virga -- precipitation that's in the air but not yet reaching the ground.
Will the snow stick? Tough call. Temperatures may be right around freezing the vast majority of the event. If snow is light in intensity it may only stick to grassy and typically cooler surfaces.
When will travel be most difficult? Expect possible minor impacts for this evening's rush -- especially on lightly traveled roads, ramps and bridges. Depending on precipitation type, Friday morning's rush may present complications; some areas may see an icy glaze for rush hour Friday morning, while other areas, especially those with salt and sand applied, will experience just wet or slushy roads.
What about precipitation type? All areas in the region will start off with light snow or flurries this afternoon into this evening. From SE to NW tonight and into the overnight hours precipitation will likely change to sleet and freezing rain. DC and points south and east may see plain rain by Friday morning. Favored areas to the north and west of DC will likely hold onto frozen precipitation of some type for the duration of the event, but these areas are also likely to see less precipitation overall.
When will conditions improve? Cooler areas that see all frozen precipitation are likely to be somewhat treacherous Friday AM; however, for DC and points south and east plain rain may ameliorate the conditions somewhat. Temperatures everywhere will climb above freezing by mid-morning Friday.
Could it fizzle out? Yes, for two reasons: (1) Some models are hinting that this storm system will be weak and suppressed south, if that is the case we may see nothing more than flurries. (2) Temperatures will be very close to 32 during much of the event. Note that as little as a few miles may separate the line between each precipitation type: snow and sleet; sleet and freezing rain; freezing rain and plain rain.
Could the storm bring more snow than expected? Perhaps. Some models are also suggesting some rapid intensification of the storm Thursday night which would increase precipitation. However, this is exactly when a changeover from snow to ice or rain (south and east) is most likely to occur. Areas that remain snow, however -- most likely the far northwest suburbs -- could see a nice burst of snow with accumulations higher than forecast.
What are other forecasters saying? Most forecast outlets are calling for light accumulations of snow (around an inch or two) with an icy coating possible on top.
What's the bottom line? For the immediate DC area, a 40% chance of snow accumulations of around an inch followed by a period of sleet, freezing rain, and perhaps plain rain (especially south and east of town); 25% chance of 2-3" of snow followed by a mix which may change back to snow before ending; 25% chance of little or no accumulation; 10% chance of a 'moderate' snowfall of 3-6" or so. Overall amounts will be slightly higher north and west of town and a bit reduced south and east of town.
A fast moving and fickle winter storm arrives today with scattered flurries during the daylight hours; evening rush should be fine in almost all areas. More in the way of precipitation (from a second area of low pressure) is possible tonight. The CapitalWeather.com team believes that up to an inch of snow could fall before a changeover to sleet and freezing rain (or even plain rain in spots) overnight.
 | 
10am to 5pm THURS: Scattered flurries around; temperatures 31-34. |
  Travelcast: Schoolcast (Fri.):  | |
Frequently asked Questions
Where will the heaviest precipitation fall? The heaviest precipitation will likely be south of Washington, DC. Note, however, that the further east you go from DC, the more mixing in there will be of ice and rain.
When will the snow start? Scattered flurries are possible during the daylight hours today; however, it looks like the heaviest precipitation will hold off until this evening and the overnight hours. See detailed timeline above.
Where is the precipitation now? Click here for the latest radar loop. Note that parts of the leading edge of the precipitation may be virga -- precipitation that's in the air but not yet reaching the ground.
Will the snow stick? Tough call. Temperatures may be right around freezing the vast majority of the event. If snow is light in intensity it may only stick to grassy and typically cooler surfaces.
When will travel be most difficult? Expect possible minor impacts for this evening's rush -- especially on lightly traveled roads, ramps and bridges. Depending on precipitation type, Friday morning's rush may present complications; some areas may see an icy glaze for rush hour Friday morning, while other areas, especially those with salt and sand applied, will experience just wet or slushy roads.
What about precipitation type? All areas in the region will start off with light snow or flurries this afternoon into this evening. From SE to NW tonight and into the overnight hours precipitation will likely change to sleet and freezing rain. DC and points south and east may see plain rain by Friday morning. Favored areas to the north and west of DC will likely hold onto frozen precipitation of some type for the duration of the event, but these areas are also likely to see less precipitation overall.
When will conditions improve? Cooler areas that see all frozen precipitation are likely to be somewhat treacherous Friday AM; however, for DC and points south and east plain rain may ameliorate the conditions somewhat. Temperatures everywhere will climb above freezing by mid-morning Friday.
Could it fizzle out? Yes, for two reasons: (1) Some models are hinting that this storm system will be weak and suppressed south, if that is the case we may see nothing more than flurries. (2) Temperatures will be very close to 32 during much of the event. Note that as little as a few miles may separate the line between each precipitation type: snow and sleet; sleet and freezing rain; freezing rain and plain rain.
Could the storm bring more snow than expected? Perhaps. Some models are also suggesting some rapid intensification of the storm Thursday night which would increase precipitation. However, this is exactly when a changeover from snow to ice or rain (south and east) is most likely to occur. Areas that remain snow, however -- most likely the far northwest suburbs -- could see a nice burst of snow with accumulations higher than forecast.
What are other forecasters saying? Most forecast outlets are calling for light accumulations of snow (around an inch or two) with an icy coating possible on top.
What's the bottom line? For the immediate DC area, a 40% chance of snow accumulations of around an inch followed by a period of sleet, freezing rain, and perhaps plain rain (especially south and east of town); 25% chance of 2-3" of snow followed by a mix which may change back to snow before ending; 25% chance of little or no accumulation; 10% chance of a 'moderate' snowfall of 3-6" or so. Overall amounts will be slightly higher north and west of town and a bit reduced south and east of town.
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