Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 352 AM EDT Thu Jun 27 2019 Valid 12Z Thu Jun 27 2019 - 12Z Sat Jun 29 2019 ...Thunderstorms, some containing severe weather and flash flooding, are forecast across the northern tier of the U.S. through the end of the workweek... The weather pattern over the next couple of days consists of an upper-level low that will persist over the Pacific Northwest, while a slow-moving frontal boundary at the surface remains stretched across the northern tier of the country. Showers and thunderstorms are expected to form and focus along and near this front. On Thursday, an Enhanced Risk of severe weather is in place for the Northern High Plains, as well as a Slight Risk of excessive rainfall/flash flooding. Severe weather and flash flooding are also possible in the Upper Midwest, where Slight Risks of both hazards are delineated. Widespread rainfall amounts there are expected to be 1 to 2 inches, with locally higher amounts. Severe weather and an isolated flash flood could continue into Friday for the Northern High Plains. The aforementioned upper low will cause unseasonably cold conditions, with high temperatures 15 to 25 degrees below normal in northern California and much of Oregon on Thursday. The highest elevations of the Cascades could even see some snow. Meanwhile, summer heat will prevail from the continental divide eastward, with high temperatures reaching the 90s as far north as the Northern Plains and Upper Midwest by Friday. Elsewhere, the southern tier of the country from the Southern High Plains to the Southeast could see scattered summertime thunderstorms, and a few strong storms containing locally heavy rainfall are possible in the Lower Mississippi and Tennessee Valleys on Thursday. Red Flag Warnings are in effect for parts of the Central Great Basin and Four Corners region, where fire weather conditions are elevated. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php