Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 356 PM EDT Tue May 06 2014 Valid 00Z Wed May 07 2014 - 00Z Fri May 09 2014 ...Heavy rain possible over parts of the Northern Plains... ...Temperatures will be 15 to 20 degrees below average over parts of the Northern High Plains... A quasi-stationary front extending from the Southern Mid-Atlantic westward to the Rockies and Great Basin will have a wave of low pressure develop over the Central Rockies. The wave will slowly move eastward to the Central Plains by Thursday morning. Upper-level energy flowing over the Upper Midwest to the Mid-Atlantic will trigger showers and thunderstorms over parts of the Upper Great Lakes to the Mid-Atlantic that will wane to the Mid-Atlantic by Thursday. In addition, showers and thunderstorms will develop along the dryline over parts of the Southern Plains on Tuesday evening and on Wednesday evening, expanding into parts of the Central Plains and Middle/Lower Mississippi by Thursday evening. Meanwhile, the associated upper-level trough will move eastward from the Great Basin to the Central Plains by Thursday. The energy will produce rain from parts of the Great Basin to the Northern Plains with an area of embedded showers and thunderstorms over parts of the Central Rockies through Wednesday morning. Snow will also develop over parts of the Sierras on Tuesday evening. Snow will develop over parts of the higher elevations of the Northern/Central Rockies and Eastern Great Basin overnight Tuesday through Thursday. Additionally, moisture from the Gulf of Mexico will flow northward over the Plains aiding in the development of moderate to heavy rain over parts of the Northern/Central Rockies on Thursday. Showers and thunderstorms will develop over parts of the Upper Mississippi Valley Wednesday evening into the Upper Great Lakes by Thursday morning. Elsewhere, an approaching front over the Eastern Pacific will produce light rain over parts of the Pacific Northwest Coast by Thursday morning. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php