Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 337 AM EDT Wed Jul 21 2021 Valid 12Z Wed Jul 21 2021 - 12Z Fri Jul 23 2021 ...Severe weather threat found across the Northeast today, with additional rounds of heavy rain possible over the Southwest through the end of the week... ...Midsummer heat continues across the northern and central Plains... ...Elevated to critical fire weather concerns remain throughout the northern Rockies and northern Great Basin... A cold front swinging across the Northeast this afternoon will help spark thunderstorms capable of producing damaging wind gusts and large hail. The area highlighted as having the greatest severe thunderstorm threat extends from Cape Cod to the Delmarva Peninsula. This cold front will also help rid the atmosphere of wildfire smoke that was recently transported from western North America. In the meantime, Air Quality Alerts remain in effect for parts of the Mid-Atlantic. Elsewhere, another day of scattered showers and thunderstorms is in store for the Southeast and Gulf Coast region, with isolated downpours possibly leading to localized flash flooding. Thunderstorms are also possible across western Montana as a cold front interacts with a warm and unstable airmass. A few storms could turn severe and trigger damaging wind gusts. The Summer Monsoon is expected to persist throughout the Southwest and central Great Basin for the foreseeable future. This rainfall is desperately needed for much of the region, as widespread extreme to exceptional drought has been locked in for much of the year. However, too much rain could lead to flooding concerns across vulnerable locations. Showers and thunderstorms capable of dropping over an inch of rain are expected to become more widespread by Thursday over portions of the Southwest. A Slight Risk (level 2/4) of Excessive Rainfall has been issued for both today and Thursday, including parts of Arizona, western New Mexico, and southwest Colorado. Hot and dry weather is forecast to continue across the northern and central Plains over the next few days as an upper-level ridge remains anchored over the central Rockies. Widespread high temperatures into the upper 90s and low triple digits stretch across eastern Montana and the Dakotas, while spreading farther south and east by the end of the week. Excessive Heat Warnings remain in affect across eastern Montana today as warm overnight lows combine with dangerous heat during the day. Slightly to the west, extreme drought, gusty winds, and the continuing threat of dry lighting could create elevated to critical fire weather. These conditions stretch from the northern Sierra Nevada and Great Basin to the Northern Rockies, where Fire Weather Watches and Red Flag Warnings have been issued. Snell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php