Wednesday, March 07, 2007
Alberta Clipper on Track to Bring Minor Snowfall
Team Forecast @ 12:00 PM
*Snow Advisory in effect from 7 AM to 7 PM*
Thought you were done with winter? Not so fast. Arctic air settled into the area yesterday, and today a snow-producing Alberta clipper moves through. But, as has been the case with most of our storms this winter, except for the Valentine's Day ice storm and the recent "surprise" snowstorm, only minor accumulations are expected.
When/where will the heaviest snow fall? Snow is likely to be heaviest north of DC during the morning hours, and then east of town during the afternoon.
Will the snow accumulate?
It should accumulate quite easily on grassy surfaces, sidewalks and untreated roads. Accumulation on treated roads will depend on the intensity of the precipitation. In areas where snow intensity is mostly light, the early-March sun, even through overcast skies, may help reduce accumulation. Heavier bands or bursts of snow will tend to accumulate more easily on all surfaces.
Where is the precipitation now? Click here for the latest radar loop. Note that parts of the leading edge of precipitation may be virga (precipitation in the air that is not yet reaching the ground).
When will travel be most difficult?
During the late morning through early evening. But treated roads should fair pretty well except during periods of heavier precipitation.
Will it definitely be snow and not ice or rain? Clipper systems originate from Canada, and thus usually bring very cold air with them at all levels of the atmosphere. So, we are quite confident that the metro area will see an all-snow event, with any rain staying well to the south and southeast. Ice is not a likely form of precipitation with this type of system.
When will conditions improve? The snow could impact the afternoon rush, especially east of town where precipitation may linger the longest. Conditions should quickly improve everywhere by later on the evening.
Could the storm bring more snow than expected? As the storm reforms off the coast, it could keep heavier precipitation going longer than expected, especially to the east. This could increase accumulations over those shown on the map above, but 4-5 inches would be about the absolute maximum anyone in the metro area would see.
Could the storm bring less snow than expected? The models, as indicated by our accumulation map above, are hinting at an area of reduced accumulations from DC toward points west and southwest. This is a result of the storm weakening as it passes over the mountains, and then not strengthening until it reforms to our east. It's possible that precipitation in this area could end up being even lighter than expected, which would result in less accumulation.
What are other forecasters saying? The National Weather Service is forecasting 2-4". WJLA, WUSA and WTTG are forecasting 1-3". And WRC is predicting 1-2".
What's the bottom line? A minor snowfall is expected for the metro area, with 1-2" expected for DC and points west, and 2-4" possible to the east.
Thought you were done with winter? Not so fast. Arctic air settled into the area yesterday, and today a snow-producing Alberta clipper moves through. But, as has been the case with most of our storms this winter, except for the Valentine's Day ice storm and the recent "surprise" snowstorm, only minor accumulations are expected.
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 Travelcast: Schoolcast (Wed and Thu):  | |
Frequently Asked Questions
When/where will the heaviest snow fall? Snow is likely to be heaviest north of DC during the morning hours, and then east of town during the afternoon.
Will the snow accumulate?
It should accumulate quite easily on grassy surfaces, sidewalks and untreated roads. Accumulation on treated roads will depend on the intensity of the precipitation. In areas where snow intensity is mostly light, the early-March sun, even through overcast skies, may help reduce accumulation. Heavier bands or bursts of snow will tend to accumulate more easily on all surfaces.
Where is the precipitation now? Click here for the latest radar loop. Note that parts of the leading edge of precipitation may be virga (precipitation in the air that is not yet reaching the ground).When will travel be most difficult?
During the late morning through early evening. But treated roads should fair pretty well except during periods of heavier precipitation.
Will it definitely be snow and not ice or rain? Clipper systems originate from Canada, and thus usually bring very cold air with them at all levels of the atmosphere. So, we are quite confident that the metro area will see an all-snow event, with any rain staying well to the south and southeast. Ice is not a likely form of precipitation with this type of system.
When will conditions improve? The snow could impact the afternoon rush, especially east of town where precipitation may linger the longest. Conditions should quickly improve everywhere by later on the evening.
Could the storm bring more snow than expected? As the storm reforms off the coast, it could keep heavier precipitation going longer than expected, especially to the east. This could increase accumulations over those shown on the map above, but 4-5 inches would be about the absolute maximum anyone in the metro area would see.
Could the storm bring less snow than expected? The models, as indicated by our accumulation map above, are hinting at an area of reduced accumulations from DC toward points west and southwest. This is a result of the storm weakening as it passes over the mountains, and then not strengthening until it reforms to our east. It's possible that precipitation in this area could end up being even lighter than expected, which would result in less accumulation.
What are other forecasters saying? The National Weather Service is forecasting 2-4". WJLA, WUSA and WTTG are forecasting 1-3". And WRC is predicting 1-2".
What's the bottom line? A minor snowfall is expected for the metro area, with 1-2" expected for DC and points west, and 2-4" possible to the east.
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