Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 PM EDT Sat Jul 18 2020 Valid 00Z Sun Jul 19 2020 - 00Z Tue Jul 21 2020 ...Very hot temperatures and heat indices are forecast from the Plains to the East Coast... ...Severe weather and flash flooding are possible with thunderstorms in the Upper Midwest to Great Lakes... An upper-level ridge will lead to widespread heat across central and eastern portions of the country through the beginning of next week. Heat Advisories and Excessive Heat Warnings have been issued for parts of the Central Plains and Midwest today with heat indices ranging between 105 and 110 degrees. A cold front passing through should moderate temperatures there on Sunday, but the heat will spread eastward on Sunday toward the Ohio Valley, Mid-Atlantic, and Northeast. Excessive Heat Warnings are in place on Sunday for parts of the northern Mid-Atlantic including the Philadelphia metro area, with Heat Advisories throughout other parts of the region. Record highs could be broken along with record warm minimum temperatures. Farther west, abnormally hot conditions are possible in parts of the Southwest, and there is an Excessive Heat Warning for the immediate Phoenix metro area on Sunday. A cold front passing through the Midwest and Great Lakes region will provide a focus for thunderstorms through tonight. An Enhanced Risk of severe weather is in place for parts of the Upper Mississippi Valley today, and Slight Risks of severe weather and flash flooding are delineated from that area eastward into the Great Lakes through the night. As the cold front pushes eastward, the Lower Great Lakes could see severe weather on Sunday. Meanwhile farther west, the front is expected to meander across the Central Plains and Middle Mississippi Valley on Sunday and Monday, providing a focus for storms. A Slight Risk of flash flooding is in place for parts of Kansas and Missouri where storms could produce the heaviest rainfall, and locally heavy rainfall is also possible in the Ohio Valley. Severe weather is a threat for the Central High Plains on Sunday as well, and scattered thunderstorms are also possible in the Southern/Central Rockies to Southern High Plains. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php