Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 441 AM EDT Wed Jun 18 2014 Valid 12Z Wed Jun 18 2014 - 12Z Fri Jun 20 2014 ...Showers and thunderstorms continue along the northern Rockies and into the High Plains and even high elevation snows... ...Strong to severe storms and flash flooding are possible along a boundary draped from the central Plains to the Middle Atlantic... The impressive upper level low continues its slow trek eastward across the Intermountain West. Between Tuesday morning and Wednesday morning, this upper low does not move very much. This is translating to a continuous bout of precipitation along and east of the northern Rockies as a surface trough provides a focal point for the convection. Behind the cold front that has pushed southward into the central Plains, cold temperatures have filtered in and have already brought snows to portions of the high elevations of the northern Rockies and higher elevations in Utah/Wyoming. These snows will continue to happen through Thursday. By late Wednesday night, the upper level low finally swings out into the High Plains and moves towards central Canada. As the upper low makes its exit, showers and thunderstorms will follow suit and come to an end. However, scattered convection will still be possible on Thursday. All eyes have focused on the central Plains with multiple rounds of severe thunderstorms. Unfortunately, this trend will persist as a quasi-stationary front will stretch from the central Plains eastward to the Mid-Atlantic region. An unstable environment along with an abundance of moisture from the Gulf of Mexico will give way to threats such as strong to severe storms and flash flooding. These threats will continue through the central Plains and Upper Midwest/Great Lakes region on Wednesday and into Thursday. By Thursday evening, the storms firing ahead of the frontal boundary will move eastward as the front moves into the Upper Midwest and Mississippi Valley. With the convective activity moving eastward, so too will the severe weather and flash flooding. Ahead of the warm front, anomalously warm temperatures are expected especially in the Mid-Atlantic region. This marks the first heat wave of the season for the area with some places reaching heat indices over 100 degrees. In Texas, storms will keep firing off ahead of the dryline especially during the afternoon. Fanning Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php