Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 354 PM EDT Tue Sep 18 2018 Valid 00Z Wed Sep 19 2018 - 00Z Fri Sep 21 2018 ...Heavy rain is forecast for parts of the Northern Plains to Midwest... ...Flash flooding is possible in the Southwest U.S. as much above normal moisture streams in... ...Warmer than average temperatures are in place for the Central Plains to Ohio Valley... ...Conditions favorable for wildfires are forecast for parts of the Intermountain West... Over the next few days, the jet stream is expected to strengthen across the Northern Rockies and into the Northern Plains, as an upper-level trough slowly develops in the northwestern U.S. At the surface, a frontal system is set up across the Intermountain West through the Central Plains, Middle Mississippi Valley, Ohio Valley, and Northeast. This front will not move much over the next couple of days across the center of the country. This, combined with a secondary front moving through the Northern Plains, will help force possibly multiple rounds of heavy rainfall across the Northern Plains and Middle to Upper Mississippi Valley. Slight Risks of excessive rainfall/flash flooding are in effect in those areas through Thursday. Much of this area has been abnormally wet recently, which could exacerbate flooding concerns. Some thunderstorms could be strong to severe, with the Storm Prediction Center outlooks showing Marginal Risks of severe weather. On the back end of the secondary front, rain is expected in the Northern High Plains, with some snow mixing in in higher elevations of the Northern Rockies. A tropical disturbance near the southern tip of Baja California has some chance of development into a tropical cyclone per the National Hurricane Center. This plus the much above average moisture streaming in to the area will lead to the potential for heavy rain across the Southwest U.S. through Thursday. The heaviest widespread rainfall totals are expected south of the U.S. border and into Mexico, but continue to monitor the forecast for changes. Cooler weather is expected north of the aforementioned frontal system across the U.S., while warm weather prevails to the south. High temperatures in the 90s are forecast for the Central Plains to Ohio Valley and southward, which is 10 to 20 degrees above average in those areas. Meanwhile, the Northern High Plains will see high temperatures in the 50s and 60s, 10 to 15 degrees below normal for mid-September. Increasing winds in the Intermountain West combined with low humidity will lead to a wildfire risk. The Storm Prediction Center has outlooked Critical Risks of fire weather in these areas. Red Flag Warnings are in effect through Wednesday evening in much of Utah and Wyoming. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php