Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 342 AM EDT Tue Aug 22 2017 Valid 12Z Tue Aug 22 2017 - 12Z Thu Aug 24 2017 ...Cold front sweeping across the eastern U.S. will bring with it heavy rainfall and severe weather... ...Showers and thunderstorms expected to continue across the Southern Rockies... A cold front stretched from southeastern Canada to the Rockies will be the focus for weather across the eastern U.S. during the short term period. On Tuesday, this front will move southeastward across the Great Lakes, Tennessee Valley, Mississippi Valley and the Southern Plains. With copious amounts of moisture in place along with instability, convection will continue developing along and ahead of the front. On Tuesday the heaviest rainfall will move from the Middle Mississippi Valley and into the Southern Plains/Lower Mississippi Valley. Farther north, the cold front will also begin approaching the Lower Great Lakes and New England--bringing chances of flash flooding and severe weather to these regions. As the cold front slows along the Red River Valley late Tuesday night, heavy rainfall will also develop in this region and slowly push southward. By Wednesday, the cold front will approach the East Coast while sinking southward across the Southeast. Once again, precipitation will also move along the front. By Thursday morning, showers and thunderstorms will concentrate in the coastal Carolinas and north/central Texas. Thunderstorms across the Southern Rockies will continue to fire off each afternoon over the short term period. Expect a marginal risk for flash flooding as some of these storms could produce heavy downpours that may lead to flash flooding. A slow-moving upper level low will linger along the California coast--which will give way to scattered showers and thunderstorms across areas in California and the Great Basin. The heaviest rainfall is forecast to be in the Sierra Nevada mountain range. Meanwhile, farther north, a cold front will move across the Pacific Northwest on Wednesday night/Thursday morning, bringing light showers especially in the Northern Rockies. Typical summertime thunderstorms will occur along the Gulf Coast states each afternoon. There will be an increase in coverage on Wednesday as the cold front approaches the coastline. Florida can also expect an increase in thunderstorm activity as an inverted trough approaches its Atlantic coastline this morning. In terms of temperatures, cooler conditions will settle in behind the strong cold front sweeping the eastern U.S. In fact, most of the country east of the Rockies will be below average on Thursday. Ahead of the incoming cold front, the Pacific Northwest and northern Rockies will experience warmer than normal temperatures. As the cold front pushes across this region, temperatures will drop back down to near normal or slightly below normal. Reinhart Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php