Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 342 AM EDT Mon May 16 2016 Valid 12Z Mon May 16 2016 - 12Z Wed May 18 2016 ...Strong to severe thunderstorms possible over parts of the central and southern High Plains... ...Heavy rain possible over the central Plains into the middle Mississippi valley and parts of the Western Gulf Coast... ...Temperatures will be 10 to 20 degrees below average from the Central Appalachians westward to the Central Rockies... As an upper-level low sinks toward the Great Basin a surface cold front will slowly move through the Four Corners region and cross the Southern Rockies today, then track across the southern and central plains through midweek. Showers and thunderstorms are forecast from the Pacific Northwest to the southern Plains and western Gulf Coast, with mountain snow possible in the Northern/Central Rockies and the Wasatchs at the highest elevations. The precipitation will expand eastward into the Midwest and Ohio/Tennessee valleys by tonight and early Tuesday morning. Additionally, showers and thunderstorms will develop over parts of the Southeast by Tuesday morning. Precipitation will taper off by late this afternoon across the Pacific Northwest. Conditions will be favorable for some of the storms to become rather strong or severe across the southern and central Plains. The Storm Prediction Center has issued a slight risk for the Texas and Oklahoma today, with an enhanced area over the panhandles. The area of elevated risk will shift south on Tuesday - much of Texas and western Arkansas/Louisiana with a slight risk and the Texas Hill Country with an enhanced risk. Heavy rain and flash flooding will be another threat with the showers and thunderstorms across the southern and central Plains. Excessive rainfall outlooks have been issued for the western Gulf Coast and central Plains/middle Mississippi valley. Rain showers across the Northeast will slowly diminish by Tuesday as the upper-level low over the Northeast moves eastward into Eastern Canada. A weak system over South-Central Canada will move southeastward to the Lower Great Lakes by Tuesday morning expanding showers and thunderstorms into parts of the Middle Missouri valley to parts of the Lower Great Lake. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php