Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 421 PM EDT Sun May 22 2016 Valid 00Z Mon May 23 2016 - 00Z Wed May 25 2016 ...Heavy rains and severe storms possible for portions of the Great Plains and Mississippi Valley early this week... ...Daytime temperatures will remain below normal from the West Coast to the Rockies... ...Damp and dreary conditions should gradually diminish across the Mid-Atlantic states... Showers and thunderstorms are expected ahead of a frontal boundary edging eastward out into the Great Plains Sunday night into Monday. An axis of Gulf moisture streaming northward between a broad trough in the West and upper ridge over the Midwest should fuel heavy rains within developing storms...and some storms will have the potential to become severe. The northern portion of the front should progress through the Upper and Middle Mississippi Valley Monday night into Tuesday...shifting the threat for heavy rain and severe weather eastward into Minnesota...Iowa...and Missouri. However...the southern portion of the boundary will remain stalled in the High Plains...keeping the potential for showers and thunderstorms in Texas...Oklahoma...and Kansas. Daytime temperatures will remain below normal from the West Coast to the Rockies beneath an expansive upper trough carved out over the western half of the Nation. In addition to the cool conditions...widespread shower activity is expected during the afternoon hours...with snow even possible for the higher elevations of the Rockies and Sierra Nevada Range. Damp and dreary conditions should gradually improve across the Mid-Atlantic states early this week as a closed low aloft begins to weaken and lift northeastward. Scattered showers will still be possible on Monday...but activity should diminish and temperatures should be noticeably on the rise by Tuesday. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php