Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 331 PM EDT Thu Jun 20 2019 Valid 00Z Fri Jun 21 2019 - 00Z Sun Jun 23 2019 ...Severe thunderstorms and flash flooding possible for portions of the central and eastern U.S... ...Chilly conditions expected for the Great Basin and northern Rockies with snow possible for the higher elevations of western Montana... ...Above average temperatures expected from the Southern Plains to the Southeast... A deepening surface low pressure system crossing New England tonight is expected to bring widespread rain and thunderstorms, with the potential for heavy rainfall and flash flooding for areas from the central Appalachians to the Northeast. Severe weather is also possible along/ahead of the surface front through tonight from the Southeast to the Mid-Atlantic. Rain and thunderstorms may persist into Friday across much of New England as the low continues to deepen offshore as it moves relatively slowly northeastward toward the Canadian Maritimes. Farther west, a wavy quasi-stationary surface front extending from the Central Plains to the Mid-Mississippi Valley will also produce areas of showers and thunderstorms tonight from the Central/Northern Plains to portions of the Midwest, with severe thunderstorms a possibility. A relatively strong upper-level trough and cold front crossing the western U.S. today is expected to bring rain and mountain snow to much of the central/northern Rockies through Friday, with the greatest potential for accumulating snows across the higher elevations of western Montana, where several inches of snow are possible. Cold air associated with the upper-level trough will also result in high temperatures on Friday 15 to as much as 30 degrees below average across areas from the Great Basin to the northern/central Rockies. As this system shifts east toward the central U.S. on Friday, lift will increase along the preexisting surface front, and a round of more widespread/heavier showers and storms are possible later Friday across portions of the Northern Plains and Midwest. Severe weather and flash flooding will once again be possible. Meanwhile, areas from the Southern Plains to the Southeast will remain warm to hot, with only isolated showers and thunderstorms possible. High temperatures on Friday are forecast to be 5 to 10 degrees F above average across much of this area. Slightly cooler temperatures are possible for the Southern Plains by Saturday due to more cloud cover associated with the incoming upper-level trough and cold front. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php