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Short Range Public Discussion
(Latest Discussion - Issued 0815Z Aug 21, 2018)
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Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 408 AM EDT Tue Aug 21 2018 Valid 12Z Tue Aug 21 2018 - 12Z Thu Aug 23 2018 ...Heavy rain and severe weather expected across the Ohio Valley and Mid-Atlantic today... ...Fire weather and air quality concerns continue for portions of the Western U.S... A very strong low pressure system will lift across the Ohio Valley and Lower Great Lakes today. From this will stretch a robust cold front which will drape southward into the southern Plains. Ahead of the frontal system, warm and moist air will be transported from the Gulf of Mexico spawning widespread showers and thunderstorms across much of the eastern U.S. and Southeast. The heaviest rainfall and best thunderstorm potential will be located along the frontal boundary and close to the center of low pressure. A slight risk of severe weather is possible for the Ohio Valley and Mid-Atlantic as well as a slight risk for flash flooding. Later on into Wednesday, the cold front will push off the East Coast--and so too will the precipitation. Some heavier precipitation will continue to move across New England as the cold front sweeps across this region. Meanwhile, behind this system, a large area of high pressure will set in across the eastern U.S., resulting in much drier weather to finish out the work week. Fire weather risks will continue to be elevated across the West, especially for parts of the Great Basin today. Red flag warnings are in effect for a small area of northeast California and northeast Nevada. Air quality also remains a concern due to the smoke from ongoing fires. Air Quality Alerts are in effect for all of the Pacific Northwest, northern Idaho, and western Montana. Furthermore, fires burning in British Columbia, Canada are transporting smoke southward into portions of Minnesota, where an Air Quality Alert is also in effect. Monsoonal moisture will surge back into the Southwest by Tuesday and expand across the Great Basin and Southern/Central Rockies, resulting in scattered to widespread showers and thunderstorms through the day. These storms will then shift eastward to encompass a portion of the central and southern Plains by mid-week. The best shower and thunderstorm potential will be in the afternoon and early evening each day. Some of these storms could produce flash flooding, especially in favorable terrain and urban areas, as well as across burn scar regions. Flash flooding will also be a concern in the high plains, where above normal rainfall has already occurred over the past week. Reinhart/Wix Graphics available at