Monday, January 31, 2005
Storm recap and the week ahead
Jason Samenow @ 7:34 AM
As CapitalWeather.com predicted, about 2-3" of snow and ice fell across the DC metro area between Saturday night and Sunday afternoon. Isolated areas got a little more or a little less than this within the metro region.
Here are some accumulation totals from across the area:
The Washington Post published this article on the storm: Weekend Snowstorm Gives Road Plows an Edge
Post mortem forecast assessment
We first mentioned the possibility of some weekend storminess on Monday and went back and forth on the forecast until we got a firmer grip on the situation Thursday night. On Friday night, when it was time to make the call on snowfall amounts, CapitalWeather nailed it -- forecasting 2-3" of snow for the DC area which was exactly the amount that fell. On Saturday night, when other forecasters (e.g. at the National Weather Service) lowered forecast amounts due to sleet and freezing rain, CapitalWeather stuck to its forecast and correctly predicted a changeover back to snow towards dawn Sunday. CapitalWeather correctly forecasted the time of onset of the precipitation Saturday evening, although the precipitation lasted a few hours longer than we expected on Sunday.
While CapitalWeather got the DC area right (which is our focus), its snowfall accumulation map was flawed to the south and southwest. Areas that were forecast to get 3-5" in some cases got just 1/2" of ice/snow. This occurred due to a shallow warm layer aloft that caused the precipitation type to be mostly freezing rain and sleet rather than snow in those areas. We'll try to do better for our Charlottesville and Fredericksburg readers the next time.
This week's weather
Expect dry conditions and moderating temperatures each day--starting with highs around 40 today warming to near 50 by the end of the week. Overnight lows will moderate from the low 20s to the low 30s. There is some uncertainty about the late week forecast as there may be a coastal storm. If that happens, it will not be as warm as currently forecast.
Expect dry conditions and moderating temperatures each day--starting with highs around 40 today warming to near 50 by the end of the week. Overnight lows will moderate from the low 20s to the low 30s. There is some uncertainty about the late week forecast as there may be a coastal storm. If that happens, it will not be as warm as currently forecast.
Here are some accumulation totals from across the area:
| Select NWS Reports
Virginia National Airport: 2.6" Dulles Airport: 2.8" Annandale: 3" West Falls Church: 4" Centreville: 2.8" Vienna: 2.5" Maryland Annapolis: 3" Columbia: 2.5" Gaithersburg: 2.9" Oxon Hill:2.5" BWI: 1.7" |
CapitalWeather reports
DC Jason, NW: ~3" snow/ice Virginia Rick and Josh, Springfield: 3" Mike and Nikolai, McLean: 3" KCM, Arlington: 3" Kevin: Oakton: 3.2" [Jamie/Scott, Charlottesville area: 0.5" snow/ice] Maryland Steve S, Potomac: 2" JW, Montgomery County: 2.5" Mark, Greenbelt: 2"+ |
The Washington Post published this article on the storm: Weekend Snowstorm Gives Road Plows an Edge
Post mortem forecast assessment
We first mentioned the possibility of some weekend storminess on Monday and went back and forth on the forecast until we got a firmer grip on the situation Thursday night. On Friday night, when it was time to make the call on snowfall amounts, CapitalWeather nailed it -- forecasting 2-3" of snow for the DC area which was exactly the amount that fell. On Saturday night, when other forecasters (e.g. at the National Weather Service) lowered forecast amounts due to sleet and freezing rain, CapitalWeather stuck to its forecast and correctly predicted a changeover back to snow towards dawn Sunday. CapitalWeather correctly forecasted the time of onset of the precipitation Saturday evening, although the precipitation lasted a few hours longer than we expected on Sunday.
While CapitalWeather got the DC area right (which is our focus), its snowfall accumulation map was flawed to the south and southwest. Areas that were forecast to get 3-5" in some cases got just 1/2" of ice/snow. This occurred due to a shallow warm layer aloft that caused the precipitation type to be mostly freezing rain and sleet rather than snow in those areas. We'll try to do better for our Charlottesville and Fredericksburg readers the next time.
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