Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 312 PM EST Sat Feb 21 2015 Valid 00Z Sun Feb 22 2015 - 00Z Tue Feb 24 2015 ...Heavy rain possible for parts of the Lower Mississippi Valley and the Central Gulf Coast... ...Heavy snow possible for parts of the Central Rockies and Great Basin... ...Temperatures will be 20 to 35 degrees below average from the Upper Midwest to the Southern High Plains... A front extending from the Mid-Atlantic southwestward to the Southern Plains then westward across parts of the Southwest will develop a wave of low pressure over the Ohio Valley that will move northeastward to Eastern Canada by Monday. The wave will pull the front northward to Northern New England by Sunday afternoon before the boundary moves off the East Coast and into the Gulf of Mexico by Monday. The system will produce light to moderate snow over parts of the Mid-Atlantic into New England on Saturday evening with the light to moderate snow moving to New England by early Sunday morning. The snow over New England will end by Sunday morning. In addition, light to moderate rain will develop over parts of the Tennessee/Southern Ohio Valleys and move eastward off the Southeast/Southern Mid-Atlantic Coast by Sunday afternoon. Between the rain/snow line, an area of rain/freezing rain and sleet will develop over parts of the Mid-Atlantic through early Sunday morning. An area of showers and thunderstorms will also develop over parts of the Lower Mississippi Valley/Western Gulf Coast through Sunday morning. Additionally, a cold area of high pressure over West-Central Canada will move southeastward to the Middle Mississippi Valley by Monday. Circulation around the high pressure will produce upslope flow over parts of the Northern/Central Rockies producing an area of snow over the region through Sunday evening. The snow will sink southward to the Southern Rockies/Southern Plains also by Sunday evening. Rain will develop over parts of the Southern High Plains on Sunday morning that will move southward to the Southern Plains by Sunday night/Monday morning. An area of rain/freezing rain and sleet will develop between the rain/snow line over the Southern Plains into parts of the Lower Mississippi Valley on Sunday afternoon into Monday. Showers and thunderstorms will also develop over parts of the Western Gulf Coast Sunday afternoon into Monday. Meanwhile, upper-level energy over the Pacific Northwest will move southward to Southern California/Great Basin developing a closed upper-level low by Monday. The system will produce areas of light to moderate snow over parts of the Great Basin that will move into parts of the Central Rockies and California Sunday into Monday. Rain will also develop over parts of Southern California by Sunday morning expanding into parts of the Southwest by Sunday evening into Monday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php