89th American Meteorological Society Annual Meeting

Sunday, 11 January 2009
The February 2007 “Valentine's Day Storm”: diagnosis and impact on the Washington, DC area
Phoenix Convention Center
Elizabeth J. Thompson, Valparaiso University, Valparaiso, IN; and B. J. Lasorsa and S. Zubrick
The so-called “Valentine's Day Storm” was a Category 3 "Major" winter storm according to the Northeast Snowfall Impact Scale. It began on 12 February 2007 in the Central Plains, continued to affect the Midwest and the Middle Atlantic States on 13 and 14 February 2007, then finally the Northeast region of the United States through 15 February 2007. The National Weather Service (NWS) Baltimore/Washington County Warning Area (the Northern Virginia/Maryland/Eastern West Virginia region) was one of the areas heavily impacted on 13 and 14 February 2007.

This case study focuses on the Valentines Day Storm's impact on the Washington, DC area on 13 and 14 February 2007. Analyses of upper air maps at standard pressure levels, high-resolution surface plots, numerical model forecasts, soundings, ASOS observations, and satellite and radar imagery were constructed to understand the development of the winter storm. Forecasting products from NWS Baltimore/Washington, the Storm Prediction Center, and the Hydrometeorological Prediction Center were also reviewed. In addition, an analysis was performed concerning the forecasting challenges that arose in determining the dominant winter precipitation type prior to the beginning of the heaviest precipitation on 14 February 2007 in Washington, DC. The results of the analysis showed that the limitations of the numerical models available contributed to the false prediction of freezing rain as the dominant precipitation type during this time period; heavy sleet/ice pellets were actually observed instead. Finally, local media sources were consulted to gain a further understanding of the storm's societal impact.

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