Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 328 PM EDT Wed Aug 21 2019 Valid 00Z Thu Aug 22 2019 - 00Z Sat Aug 24 2019 ...Severe thunderstorms and heavy to excessive rainfall possible today across parts of the Northeast, with the heavy rain threat extending westward into the Central Plains through Friday... ...Showers and thunderstorms are also likely across parts of the Northwest, Southern Rockies, and Central Gulf Coast... ...Another day of dangerous, potentially record-breaking, heat across the Southwest with heat and humidity continuing through Wednesday across parts of the South... Showers and thunderstorms are likely ahead of a cold front advancing into the Northeast this afternoon. Some of the storms could be capable of severe weather and flash flooding with both WPC and SPC highlighting slight risks for this region through tonight. The western portion of this boundary from the Mid-Atlantic to the Central Plains will be slower to move increasing the threat for heavy to excessive rainfall as moisture pools along the front. Flash flooding and strong to locally severe thunderstorms will be possible through the rest of the week. Behind this front, daytime temperatures could be 5 to 10+ degrees below normal from the Northern Plains to the Upper Midwest. Elsewhere, a cold front through the Northwest states will bring scattered showers and thunderstorms across the Northern Rockies to the Northern High Plains into Thursday. Locally strong to severe thunderstorms are possible. Monsoonal moisture into the Southern Rockies/High Plains may also bring a threat for locally heavy rainfall. And tropical moisture streaming north through the Gulf of Mexico may support heavy rainfall across parts of the Central Gulf Coast states Thursday night into Friday. Excessive heat continues this afternoon across the Southwest where high temperatures near and above 110 degrees could set records, with daytime highs well into the 90s expected through the Great Basin as well. A slight cool down is expected to arrive by Thursday following the passage of a cold front. Heat advisories also remain in effect through tonight across parts of the Southern Plains and Lower Mississippi Valley, with cooler temperatures arriving on Thursday. Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php