Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 344 AM EDT Tue Jul 20 2021 Valid 12Z Tue Jul 20 2021 - 12Z Thu Jul 22 2021 ...Midsummer heat found throughout the northern and central Plains... ...Elevated fire weather concerns continue across the northern Rockies and northern Great Basin... ...Isolated chances for severe thunderstorms and flash flooding possible for the Lower Great Lakes and Northeast today... A persistent, but gradually weakening upper-level ridge over the central U.S. will provide a continuing stretch of above average temperatures across the northern and central Plains through at least midweek. Widespread high temperatures into the upper 90s and low triple digits are forecast here, which is slightly lower than what was felt yesterday. These warm temperatures and lack of rain will likely worsen the ongoing severe to exceptional drought found throughout the region. Excessive Heat Warnings remain in effect across eastern Montana. Farther west, the combination of extreme drought, gusty winds, and dry lightning will produce another day of fire weather concerns for the northern Great Basin and northern Rockies. Thunderstorms ahead of an advancing cold front entering the Pacific Northwest today are likely to produce little rainfall, but lightning could reach the dehydrated terrain and spark new wildfires. Red Flag Warnings are in effect and stretch from northern California to Wyoming. It wouldn't be a mid-July day without thunderstorm chances across parts of the Lower 48. The areas with the greatest chances of seeing summer storms today include the Northeast, Lower Great Lakes, Southeast, and Southwest. A cold front crossing the Lower Great Lakes this afternoon may produce a few isolated severe thunderstorms capable of triggering damaging wind gusts and hail. This cold front and associated thunderstorms are forecast to shift into New England and coastal sections of the Northeast on Wednesday. For the Southeast and Gulf Coast States, a lingering frontal boundary bisecting the region will be the focus for additional rounds of slow-moving thunderstorms today. The main concern with these storms will be associated with heavy rainfall and scattered flash flooding. A Slight Risk (level 2/4) of Excessive Rainfall has been issued for parts of northeast Georgia and South Carolina, where brief downpours could produce over an inch of rain in a relatively short period of time. Meanwhile, the Southwest Monsoon is expected to continue with scattered chances of thunderstorms through much of this week. As a result, isolated instances of flash flooding will remain a possibility between the Southwest and central Great Basin. Snell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php