Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 358 AM EDT Fri Jul 22 2022 Valid 12Z Fri Jul 22 2022 - 12Z Sun Jul 24 2022 ...Searing heat wave to engulf much of the Heartland, Mid-South, and East Coast this weekend.... ...Rounds of severe weather to traverse the Midwest & Northeast today; Enhanced Risk for severe storms in the Midwest on Saturday... ...Monsoonal moisture to bring locally heavy rains and isolated flash flooding across portions of the Southwest into the southern Rockies; strong thunderstorms & heavy rain possible across the South today... ...Critical Fire Weather Risk in eastern Idaho today... A strengthening upper level ridge stretching from the Southwest to the East Coast will keep stifling heat in the forecast from the Desert Southwest to the Northeast this weekend. Heading into today, Excessive Heat Warnings were issued for much of the Desert Southwest and a large portion of the Central Plains and Middle Mississippi River Valley are under Heat Advisories. Daytime highs will soar into the triple digits in these respective areas today with another day of mid-90s for highs in the Ohio Valley, Mid-Atlantic, and Northeast (heat indices close to 100 for some). By Saturday, sizzling temperatures take hold of the Midwest and Central Plains with forecast high temps likely to surpass the century mark. Temperatures also heat up into the upper 90s in the Northeast with record highs possible from the central Rockies to the Megalopolis of the Northeast. The heat wave finally crescendos on Sunday when the Northeast sees the return of oppressive humidity levels combined with upper 90s highs, resulting in record highs and >105 heat indices in parts of the Northeast and Mid-Atlantic. The Central Plains will also have to stay cool with highs eclipsing the century mark once again. It is also important to note that Sunday morning features the potential for numerous record warm lows with some lows in parts of the Central Plains struggling to drop below 80 degrees. There is some good news in the medium range as an approaching cold front brings a brief injection of cooler temps to the Midwest and Northeast, but the core of the intense heat shifts to the South-Central U.S. and Pacific Northwest early next week. On the northern periphery of the upper ridge positioned across the southern CONUS is a series of upper level disturbances that are set to trigger thunderstorms from the northern High Plains to the Northeast today. SPC does have three Marginal Risk (Threat level 1/5) in the Red River Valley of the North, across the Midwest, and in the northern Mid-Atlantic. By Saturday, a more potent upper trough tracking across the southern Canadian Prairies will prompt a strong cold front to sweep across the North-Central U.S., resulting in a more organized severe weather threat in the Midwest. SPC has issued an Enhanced Risk (Threat level 3/5) for portions of the Upper Mississippi River Valley, which does include the Twin Cities metro area. Damaging winds, large hail, and tornadoes are all possible within severe storms on Saturday. Some of these storms across the Midwest may also produce areas of flash flooding. By Sunday, the severe threat looks to extend from the Midwest to the eastern Great Lakes as the cold front approaches these regions next. Across the southern tier of the U.S., monsoon showers and thunderstorms will develop each day in the Southwest with heavy downpours potentially leading to areas of flash flooding. WPC has issued a Marginal Risk (Threat level 1/4) of Excessive Rainfall for parts of eastern Arizona, southern Colorado, and most of New Mexico. A stronger push of tropical moisture arrives this weekend, prompting the issuance of a Slight Risk (Threat level 2/4) of Excessive Rainfall in southeast Arizona both Saturday and Sunday, while a Slight Risk was also issued for parts of the Colorado Rockies for Sunday. In the Deep South, a Marginal Risk of Excessive Rainfall is in place today from the ArkLaTex on east to the Carolina coast and Virginia Tidewater. Torrential rainfall within slow moving thunderstorms may lead to flash flooding Friday afternoon and evening. On the fire weather front, a Critical Risk for fire weather has been posted for parts of the Snake River Plain in eastern Idaho where a dangerous combination of gusty winds, very low humidity levels, and hot temperatures support favorable fire weather conditions. Mullinax Graphics are available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php