Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 402 PM EDT Sun Jul 26 2020 Valid 00Z Mon Jul 27 2020 - 00Z Wed Jul 29 2020 ...Tropical Storm Hanna to further weaken as it moves into Northeast Mexico; torrential rainfall and severe storms expected for South Texas... ...Heavy Rainfall/flash flooding possible for parts of the Rockies and Plains over the next few days... ...Cooling trend in the Plains, becoming hotter in the Northwest, staying hot in the Northeast... Tropical cyclone Hanna has brought several inches of rain to South Texas as it made its way further inland today. Some of the highest observations so far have surpassed 12 to 14 inches. Hanna is expected to weaken and dissipate over Mexico by early Tuesday morning but periods of 2 to 3 inch/hour rain rates may continue into Monday. The additional rainfall will likely cause urban and river flooding across parts of the western Gulf Coast region, that could become life threatening especially from the southern Texas coast to the Lower Rio Grande Valley. The concern for dangerous flooding in South Texas due to Hanna has maintained a High Risk for excessive rainfall through Sunday night. For more information on Hanna's status and expected track, see advisories from the National Hurricane Center. The risk for excessive rainfall and localized flooding concerns will remain elevated from the Four Corners/Southern Rockies region and into the Plains/Midwest into Monday and then into the parts of the Ohio Valley and Northeast by Tuesday. During this time monsoonal moisture will continue to advect northward into the Southwest and round the ridge over the central U.S. Meanwhile a Canadian low pressure system and associated cold front will slowing move through the Plains and Great Lakes region. Showers and thunderstorms will fire up along and ahead of this feature, keeping much of area wet for a few days. A Moderate Risk for flash flooding is forecast from the central High Plains to Corn Belt into Sunday night, portions of the Southern Rockies, Southern and Central Plains Monday (Slight risk), and in and near Oklahoma on Tuesday (Slight Risk). Cooler temperatures will move into the central U.S. with the aforementioned cold front, which will bring a pleasant reprieve from the recent hot conditions. Across the the Northwest, temperatures will warm up again reaching the 90s to near triple digits. Hot and humid conditions will persist into midweek with heat indices in the Northeast reaching at or above 100 degrees during the afternoon into Tuesday. Record highs are possible across portions of the Mid-Atlantic States and Southern New England as temperatures soar well into the 90s Sunday through Tuesday. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php