Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 348 AM EDT Mon Jul 22 2019 Valid 12Z Mon Jul 22 2019 - 12Z Wed Jul 24 2019 ...There is a slight risk of severe thunderstorms over parts of the Mid-Atlantic into Southern New England... ...There is a slight risk of excessive rainfall from parts of the Tennessee Valley roughly northeastward to Southern New England... ...There is an embedded region of moderate risk of excessive rainfall from parts of the Eastern Tennessee Valley across parts of the Central Appalachians into parts of Northern Mid-Atlantic ... The dangerous heat wave which enveloped much of the Midwest to the East Coast is finally breaking on Monday as a front drops southward across parts of the East. Showers and thunderstorms will accompany this boundary from the Northeast to the Southern Plains with heavy to excessive rainfall and severe weather possible. The boundary will be slow moving, especially across parts of the Northern Mid-Atlantic/Central Appalachians, which will increase the threat for flash flooding. WPC highlights the region from Northern New Jersey southwestward to parts of the Eastern Tennessee Valley within a moderate risk of excessive rainfall on Monday. A slight risk extends from parts of Southern New England to the Western Tennessee Valley/Lower Mississippi Valley. More widespread showers and thunderstorms develop over parts of the Southeast and Gulf Coast states on Monday. This boundary will usher in a much appreciated cooler airmass with most of the country east of the Rockies with temperatures 10 degrees below average. In addition, the front will move off most of the East Coast and most of the Gulf Coast by Wednesday. Monsoonal moisture and daytime heating will aid in producing showers and thunderstorms over parts of the Southern/Central Rockies into parts of the Southwest on Monday and Tuesday afternoon into the late evening. A front moving into the Pacific Northwest on Tuesday will produce rain across the Northwest and Northern Rockies. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php