Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
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193 FXUS21 KWNC 241806 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT July 24 2026 SYNOPSIS: Strong mid-level high pressure is forecast to bring a prolonged heat wave to the West through the beginning of August. Antecedent dryness along with the likelihood of above-normal temperatures and below-normal precipitation during the next two weeks supports an increased risk for the Rapid Onset of Drought to parts of the Great Plains and Corn Belt. A moisture surge associated with a tropical cyclone tracking northwest across the East Pacific along with the ongoing/predicted heat wave favors a renewal of an enhanced Monsoon during early August. HAZARDS High risk of extreme heat for portions of the Southwest, Great Basin, and California, Sat-Sun, Aug 1-2. Moderate risk of extreme heat for much of the Southern Plains, Southwest, Great Basin, and California, Sat-Tue, Aug 1-4. Slight risk of extreme heat for most of the western two-thirds of the CONUS and Southeast U.S., Sat-Fri, Aug 1-7. Slight risk of extreme heat for the Midwest, Wed-Fri, Aug 5-7. Slight risk of heavy precipitation for parts of the Southeast, Sat-Sun, Aug 1-2. Slight risk of heavy precipitation for parts of the Desert Southwest, Sun-Fri, Aug 2-7. Rapid onset drought (ROD) possible for parts of the Great Plains and Corn Belt. DETAILED SUMMARY FOR MONDAY JULY 27 - FRIDAY JULY 31: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR SATURDAY AUGUST 01 - FRIDAY AUGUST 07: The GEFS and ECENS are in good agreement and remain consistent in showing a highly amplified 500-hPa ridge peaking in strength on August 1st when it becomes centered over the western Contiguous U.S. (CONUS). Mulit-model ensemble mean solutions have trended stronger with this ridge and the ECENS has 500-hPa heights close to 600 dm over southern Nevada. This anomalous mid-level ridge continues to support a moderate to high risk of extreme heat throughout a large area of the western CONUS. On August 1, the National Blend of Models indicates near or record daily highs for parts of Arizona, California, and Nevada including 102 Deg F at Reno. A high risk of extreme heat, valid August 1-2, is posted for the Desert Southwest, Great Basin, and California, where the GEFS and ECENS Probabilistic Tools (PETs) depict maximum temperatures having more than a 60% chance of exceeding the 85th percentile. Maximum temperatures may exceed 115 Deg F in the Desert Southwest, while the Central Valley of California heats up to near 105 Deg F. A moderate risk (40-60% chance) of extreme heat was extended through August 4th based on the PETs and uncalibrated GEFS and ECENS temperature anomalies. The moderate risk includes much of Oklahoma and Texas where heat index values could reach 110Deg F. To the east of the Mississippi River, spread among the GEFS and ECENS has decreased today with a consensus towards a less amplified 500-hPa trough over the eastern CONUS. Late in week-2 (August 5-7), model guidance including the PETs and uncalibrated ECMWF heat index tool indicate that anomalous heat may develop over the Middle Mississippi and Ohio Valleys. Therefore, a slight risk of extreme heat was introduced to these areas, beginning on August 5. According to the U.S. Drought Monitor valid July 21, abnormal dryness (D0) and moderate drought (D1) expanded this past week across the Dakotas where Rapid Onset Drought (ROD) is well underway. Increasing 30-day precipitation deficits, high evapotranspiration rates, and the increased chance of above-normal temperatures and below-normal precipitation during the next two weeks support an enhanced risk of ROD across even more of the Great Plains and Corn Belt. Tropical Depression 7-E formed in the East Pacific on July 24. The National Hurricane Center forecasts it to become a major hurricane as it tracks northwestward. The deterministic GFS and ECMWF models and their ensemble members are tightly clustered with this tropical cyclone tracking northwestward, favoring a moisture surge north from the Gulf of California into the Desert Southwest. As the western CONUS ridge axis shifts northward, there would be an increasing chance of an enhanced Monsoon. Beginning on Aug 2, a slight risk of heavy precipitation is posted for the Desert Southwest where the PETs generally depict 3-day precipitation amounts exceeding the 85th percentile and 0.5 inch. A front is expected to become stationary from the coastal Carolinas southwest to the Florida Panhandle later next week. Through August 2, this front may enhance convection and the ECMWF PET supports maintaining a slight risk of heavy precipitation for parts of the Southeast. FORECASTER: Brad Pugh $$