Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 436 PM EDT Tue Apr 21 2015 Valid 00Z Wed Apr 22 2015 - 00Z Fri Apr 24 2015 ...Severe thunderstorms possible across the southern plains and lower Mississippi valley Wednesday and Thursday... ...A cold front will bring rain and thunderstorms from the Ohio valley to the Mid-Atlantic and portions of the Northeast... ...Below average temperatures will persist across the Great Lakes and the Northeast with a chance for rain and snow... A cold front moving southward across the plains will bring scattered showers and thunderstorms to portions of the central and southern plains tonight. Early Wednesday morning, a more organized area of rain and thunderstorms may develop across northern Texas and western Oklahoma and move southeastward toward the lower Mississippi valley during the day on Wednesday. Additional thunderstorms are forecast to develop late Wednesday over northern Texas in the warm and moist air south of the cold front and ahead of a dryline. Additional showers and thunderstorms will be possible on Thursday from Texas eastward to the lower Mississippi valley south of the cold front. The Storm Prediction Center is forecasting a risk of severe thunderstorms Wednesday and Thursday across these areas. Please refer to the Convective Outlook products issued by the SPC for further details on the severe weather threat. A large upper-level low pressure system continues to spin across the Upper Great Lakes this afternoon, keeping below average temperatures and scattered rain and snow showers in place. This system will persist over the next couple days, keeping a chance for rain and snow in place across much of the Great Lakes. A cold front will move across the Ohio valley on Wednesday, likely producing a focused area of showers and thunderstorms, which will move eastward into the Mid-Atlantic and parts of the Northeast. By Thursday morning a more pronounced surface low pressure system will develop along the New England coast, bringing widespread rain and possibly a few thunderstorms to much of Maine. In the wake of this low pressure system, colder air will spread eastward from the Great Lakes into the Northeast, where a mix of rain and snow is possible early Thursday. A Pacific frontal system across the Northwest this afternoon will continue to move east into the interior West by early Wednesday, spreading areas of precipitation with it. The majority of the precipitation will fall as rain at all but the highest elevations with this system as snow levels will be relatively high. Scattered thunderstorms may also be possible. Another Pacific frontal system will approach the Northwest on Thursday, bringing another round of primarily rain at all but the highest elevations. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php