Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 412 PM EDT Tue Apr 30 2013 Valid 00Z Wed May 01 2013 - 00Z Fri May 03 2013 ...Slight risk of severe thunderstorms from parts of the Midwest and Central Plains tonight and south central Texas on Wednesday... ...Critical Fire Weather conditions for the Desert Southwest through Wednesday evening... ...Heavy rainfall threat in the mid Missouri River Basin and Upper Mississippi River Valley through Thursday morning.... Another unusually cold storm system and Canadian airmass will spread across the Northern Plains tonight and Wednesday. There is a threat for periods of heavy rainfall along with thunderstorms from Kansas and Nebraska eastward into Iowa and Wisconsin through Wednesday. The cold front is expected to spread southward into Oklahoma...Texas...the Ozarks and central Great Lakes Illinois by Wednesday evening...then stall along the Mississippi River Valley on Thursday morning. Heavy rainfall and more thunderstorms are expected along the front from Louisiana northward into lower Michigan by Thursday morning. There is a winter side to the storm system moving through the central US and central Rockies. Along and behind the cold front...upwards of 4-6 inches of new snowfall will be possible in the Upper Platte River Valley of northern Colorado...western Nebraska and southeast Wyoming. Significant early May snowfall will continue to spread northeastward into portions of northeastern Nebraska...northwest Iowa...and southwest Minnesota on Wednesday night and Thursday morning. Very dry conditions and gusty winds are expected across portions of the Lower Colorado River basin...including northern Arizona...southeast California and southern Nevada through Wednesday night. Very low humidity and very warm temperatures will make for potentially-dangerous and fast-moving wildfire conditions. Across the East and Southeast...a ridge of cool...high pressure extends from the Canadian Maritime provinces into New England...the Mid-Atlantic states and southeast. A cool onshore flow off the western Atlantic should keep temperatures slightly below normal for most of the East Coast including Florida through Thursday morning. Vojtesak Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php