Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 247 AM EDT Wed May 01 2013 Valid 12Z Wed May 01 2013 - 12Z Fri May 03 2013 ...Slight risk of severe thunderstorms is possible over parts of Central Texas ... ...Heavy rain possible over the Lower Mississippi Valley/Central Gulf Coast, Parts of Southern Florida, and from the Central Plains to parts of the Upper Great Lakes.... ...Snow is possible from parts of the Central Rockies to Upper Great Lakes... ...Temperatures will be 20 to 30 degrees below average over the Central Rockies/High Plains... A front extending from the Upper Great Lakes southwestward to the Southern Rockies/High Plains will become quasi-stationary, with the eastern half moving only slightly eastward while the southwestern half advances southward into Mexico by Thursday evening. Added upper-level energy will aid in this southward plunge. The energy also aids in the development of moderate to heavy snow over parts of the Central Rockies/High Plains moving into parts of the Central Plains/Upper Mississippi Valley before waning to light snow on the Northwest side of the precipitation shield by Thursday evening. In addition to the snow, light to moderate rain will develop over parts of the Central Plains into parts of the Upper Mississippi Valley that will likewise wane to light rain over parts of the Upper/Middle Mississippi Valley by Thursday evening. But, a small sliver of light to moderate rain will continue over parts of the Southern Plains into parts of the Lower Missouri Valley on Thursday evening. Showers and thunderstorms will develop over parts of the Southern Plains stretching into parts of the Central Plains on Wednesday evening, expanding into parts of the Lower/Middle Mississippi Valley on Thursday morning into Thursday evening. Meanwhile, an upper-level low over the Central Gulf Coast will slowly move eastward to the Eastern Gulf Coast by Thursday. The energy will produce showers and thunderstorms over the Central Gulf Coast through Thursday evening. An upper-level disturbance will be ejected from the upper-level low that will move over Florida on Wednesday evening into Thursday. The perturbation will trigger showers and thunderstorms over parts of Florida through Thursday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php