Monday, March 20, 2006
Winter to overshadow arrival of Spring
Jason Samenow @ 9:00 AM
Spring arrives at 1:26pm today. With full sunshine, a light northerly wind and temperatures approaching 50 degrees, it will feel somewhat springlike. But tomorrow (spring's first full day) won't resemble anything like spring, with temperatures in the 30s and snowflakes in the air.
Special Weather Statement from National Weather Service
Will the snow stick? Probably not much. Most accumulation will occur on grassy areas due to daylight timing, warm ground and strong sun angle. Roads should remain just wet and problem free except for brief periods if/when snow falls heavily.
Will the snow affect schools? Unlikely. The flakes will start falling after decisionmaking time Tuesday morning. Any snow falling in the late morning to early afternoon is unlikely to stick. There's a slight chance of a period of snow Tuesday night which could cause a few slick spots --offering the possibility of a delay Wednesday morning.
Who will get the most snow? The west and northwest suburbs will likely see the most snow -- particularly the high spots. The mountains may receive enough to shovel.
Who will get the least snow? Areas downtown and points east should get the least amount of snow (perhaps as little as a trace). Urban heat island effects and low elevation will reduce amounts in the city. Areas to northeast will be on the northern edge of the precipitation and areas to the southeast will likely mix with rain. Also the storm will generally weaken as it moves eastward as the mountains squeeze out some of the moisture and the storm's energy is transferred to a new low forming over the ocean (and moving out to sea).
How cold will it be? Temperatures will rise to near 50 the day preceding the storm and will fall into the 30s tomorrow night. When the precipitation starts Tuesday morning, most areas will probably have surface temperatures above freezing. The air may cool to near freezing and hold there north and west of the city as precipitation falls Tuesday morning into the afternoon. Inside the beltway, temperatures will likely be between 32-37 during most of the storm, minimizing its impact.
What factors could result in more snow than forecast for the area? If a narrow band of heavy snow develops over the area and brings down some of the colder air aloft, temperatures could drop and the snow could have a bigger impact. Also, an upper level low will swing through Tuesday night and has a slight chance of bringing a second round of snow which might stand a better chance of accumulating due to its nighttime arrival.
What factors could result in less snow than forecast for the area? The precipitation will be moving into a very dry airmass which may cause some of the precipitation to evaporate. Lighter than expected precipitation would mean warmer than expected temperatures and less snow. Also, if the storm continues to trend southward, very little precipitation may reach our area.
What are other forecasters saying? Tony Pann (WUSA, 9) and Clay Anderson (WRC, 4) just mentioned a mix of rain and snow for Tuesday with no specific accumulation forecast. Tony did say if there is any accumulation, it will most likely be Tuesday night. Joe Witte (WJLA, 7) suggested a trace to an inch is possible in the metro area. Meteorologist Dave Tolleris of WxRisk.com forecasted 4-8" but that was before reviewing tonight's models which would indicate less snow than that. The National Weather Service is calling for 1-2".
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7am to 10am: Light rain, sleet and snow overspread area. |
  Travelcast: Schoolcast (Tues.): | |
Special Weather Statement from National Weather Service
Frequently Asked Questions
Will the snow stick? Probably not much. Most accumulation will occur on grassy areas due to daylight timing, warm ground and strong sun angle. Roads should remain just wet and problem free except for brief periods if/when snow falls heavily.
Will the snow affect schools? Unlikely. The flakes will start falling after decisionmaking time Tuesday morning. Any snow falling in the late morning to early afternoon is unlikely to stick. There's a slight chance of a period of snow Tuesday night which could cause a few slick spots --offering the possibility of a delay Wednesday morning.
Who will get the most snow? The west and northwest suburbs will likely see the most snow -- particularly the high spots. The mountains may receive enough to shovel.
Who will get the least snow? Areas downtown and points east should get the least amount of snow (perhaps as little as a trace). Urban heat island effects and low elevation will reduce amounts in the city. Areas to northeast will be on the northern edge of the precipitation and areas to the southeast will likely mix with rain. Also the storm will generally weaken as it moves eastward as the mountains squeeze out some of the moisture and the storm's energy is transferred to a new low forming over the ocean (and moving out to sea).
How cold will it be? Temperatures will rise to near 50 the day preceding the storm and will fall into the 30s tomorrow night. When the precipitation starts Tuesday morning, most areas will probably have surface temperatures above freezing. The air may cool to near freezing and hold there north and west of the city as precipitation falls Tuesday morning into the afternoon. Inside the beltway, temperatures will likely be between 32-37 during most of the storm, minimizing its impact.
What factors could result in more snow than forecast for the area? If a narrow band of heavy snow develops over the area and brings down some of the colder air aloft, temperatures could drop and the snow could have a bigger impact. Also, an upper level low will swing through Tuesday night and has a slight chance of bringing a second round of snow which might stand a better chance of accumulating due to its nighttime arrival.
What factors could result in less snow than forecast for the area? The precipitation will be moving into a very dry airmass which may cause some of the precipitation to evaporate. Lighter than expected precipitation would mean warmer than expected temperatures and less snow. Also, if the storm continues to trend southward, very little precipitation may reach our area.
What are other forecasters saying? Tony Pann (WUSA, 9) and Clay Anderson (WRC, 4) just mentioned a mix of rain and snow for Tuesday with no specific accumulation forecast. Tony did say if there is any accumulation, it will most likely be Tuesday night. Joe Witte (WJLA, 7) suggested a trace to an inch is possible in the metro area. Meteorologist Dave Tolleris of WxRisk.com forecasted 4-8" but that was before reviewing tonight's models which would indicate less snow than that. The National Weather Service is calling for 1-2".
Other Notes
- Pollen, UV and Air Quality Forecasts are now available under "Quick Links"
- The detailed week ahead forecast commentary (which usually is given today) is canceled due to coverage of Tuesday's winter weather.
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