Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 338 AM EDT Wed Sep 11 2019 Valid 12Z Wed Sep 11 2019 - 12Z Fri Sep 13 2019 ...Threats for severe thunderstorms and flash flooding from the Upper Midwest westward into portions of the central and northern Plains through Thursday... ...Much below normal temperatures likely from the Northern Rockies to Northern Plains, with much above normal temperatures across the Central and Eastern states... A stationary boundary set up from the Upper Great Lakes westward towards the northern High Plains will serve as a focus for potentially heavy rainfall and severe weather today. SPC shows a slight risk for severe thunderstorms along this boundary from southern Wisconsin to far southeast Wyoming, with an embedded enhanced risk across western Nebraska. WPC highlights parts of the Upper Midwest within a slight to moderate risk for excessive rainfall, with the potential for several inches of rain from northern Iowa/southern Minnesota into Wisconsin. An upper level trough across the western U.S. will advance eastward on Wednesday, eventually spinning up a robust surface low pressure system in the High Plains by early Thursday. Heavy to locally excessive rainfall is possible across parts of eastern Wyoming into the northern Plains on Wednesday. As this low lifts into the Upper Mississippi Valley on Thursday, another round of potentially heavy rainfall is expected from the Northern Plains to the Upper Great Lakes. Recent wet weather and saturated soils across this region will likely increase the flood/flash flood potential and WPC highlights much of the region within a slight risk for Thursday. This system will also drag a cold front across the Central Plains into the Mid-Mississippi Valley, with showers and thunderstorms and a threat for heavy rainfall and severe weather along the boundary as it progresses eastward Thursday into Friday. The deep troughing in the West will usher in an anomalously chilly air mass Wednesday and Thursday across the Northern Rockies into the Northern Plains with daytime highs 10 to 20 degrees below normal. As this system continues east into the Plains on Thursday, a warming trend can be expected across the West Coast states, with high temperatures returning into the 90s for the Central Valley of California. Meanwhile, east of the Rockies, upper level ridging will keep temperatures quite warm with daytime highs from the mid-80s to the mid-90s for many from the Mississippi Valley to the East Coast. These kinds of temperatures may approach or exceed record values, especially for parts of the Southern Appalachians. Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php