National Weather Service United States Department of Commerce

Heavy to Excessive Rainfall in the Central Appalachians; Severe Weather in the Mid-South; Hot Weather in Southern California

Heavy to excessive rainfall may lead to flooding today over southwest Pennsylvania into northern West Virginia, and western Maryland. Severe thunderstorms are possible this afternoon and evening in the Mid-South and across Eastern North Carolina. An extended period of hot weather is forecast for parts of coastal southern California including Los Angeles from today through Thursday. Read More >

12-hour helicity forecast

 

Figure 7: ETA 12 Hour Forecast of 250-850 mb Qn vectors,
thickness and isotachs valid 1200 UTC May 12, 1997.

 

18-hour helicity forecast

 

Figure 8: ETA 18 Hour Forecast of 250-850 mb Qn vectors,
thickness and isotachs valid 1800 UTC May 12, 1997.