175 FXUS21 KWNC 311847 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT August 31 2026 SYNOPSIS: Broad mid-level ridging is forecast to linger across the central contiguous U.S. (CONUS) from the end of week-1 into week-2 favoring a continuation of anomalous warmth and extreme heat centered across portions of the Great Plains and Mississippi Valley at the beginning of the period. The abnormally hot and dry conditions over the past few weeks are expected to continue through much of week-2, supporting a Rapid Onset Drought (ROD) risk for portions of the Central and Southern Plains and the Middle and Lower Mississippi Valley. Some areas have been removed in ROD across parts of Texas and Louisiana due to anticipated rainfall during week-1. Increased potential of Tropical cyclone activity in the East Pacific may support a surge of moisture into the western CONUS, supporting a slight risk of heavy precipitation across the Four Corner region. HAZARDS Moderate risk of extreme heat for parts of the Central and Southern Plains, and Middle and Lower Mississippi Valley, Tue-Wed, Sep 8-9. Slight risk of extreme heat for parts of the Desert Southwest, central and east-central CONUS, Tue-Mon, Sep 8-14. Slight risk of heavy precipitation across parts of the Great Basin, Central and Southern Rockies, southern California, and Southwest, Tue-Sat, Aug 8-12. Rapid Onset Drought (ROD) risk for portions of the Central and Southern Plains and the Middle and Lower Mississippi Valley. DETAILED SUMMARY FOR THURSDAY SEPTEMBER 03 - MONDAY SEPTEMBER 07: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR TUESDAY SEPTEMBER 08 - MONDAY SEPTEMBER 14: The 0z ECENS, GEFS, and Canadian ensembles continue to have good agreement indicating mid-level ridging lingering across the south-central CONUS at the start of week-2, with significant uncertainty thereafter regarding the evolution of the ridge. The ECENS ensemble shows the greatest amplitude relative to the GEFS and CMCE, depicting a 596-dm high centered over northern Texas at the start of the period, translating to the ECENS having higher probabilities of heat than its counterparts. This pattern supports a continuation of anomalously warm temperatures (upwards of +10 deg F above normal) across the Central and Southern Plains and adjacent areas of the Mississippi Valley. A moderate risk (40-60% chance) of extreme heat remains designated for these areas where the GEFS and ECMWF Probabilistic Extremes Tools (PETs) continue to indicate at least a 40% chance of maximum temperatures exceeding the 90th percentile climatologically and where actual temperatures or heat index values exceed 105 deg F (110 deg F in the more humid areas of southern Texas). The National Blend of Models show the potential for some locations in the Southern Plains reaching or exceeding record breaking high temperatures. The slight risk (20-40% chance) continues through Sep 11 and extends throughout much of the Midwest, and also into the Southeast. The ECENS mean favors the ridge shifting and expanding westward throughout the period with troughing developing across the northeastern CONUS, whereas the GEFS and CMCE expands the ridging eastward with more troughing across the Northwest. These differences translate to uncertainty regarding where and how the heat hazard evolves. The continued extreme heat risks during week-2 are likely being reinforced by feedback processes associated with rapidly drying soils and drought within many of the highlighted regions. The hot and dry conditions favored are also expected to elevate the risk of fire weather conditions during the period. Rapid Onset Drought (ROD) risk is designated across portions of the Central and Southern Plains and Middle and Lower Mississippi Valley. This area has registered 30- to 45-day precipitation deficits greater than 2 inches below normal and/or under half of normal, with less than an inch expected during the next two weeks. Some southern periphery areas are removed across southeastern Texas and southern Louisiana due to Tropical Depression 5 in the Gulf being monitored by the National Hurricane Center (NHC) that may bring precipitation to portions of the Gulf Coast. Across the eastern and central Pacific, there has been a pronounced uptick in tropical activity during the past week. Tropical Storms Karina and Lowell are located near 120 deg W and 145 deg W respectively. The National Hurricane Center (NHC) analyzes Karina as a major hurricane as it tracks west-northwestward. Karina along with a potential additional area highlighted with a high chance (90%) of tropical cyclone formation offshore of southwestern Mexico as of 11am PDT could lead to a renewed Gulf surge event at the end of week-1 into week-2. Therefore a slight risk of heavy precipitation for parts of the Great Basin, Central and Southern Rockies, southern California, and Southwest, Aug 8-12, where there is at least a 40-50% chance of above-normal precipitation during week-2 and enhanced precipitation indicated by various guidance tools. Localized flooding is possible as always with increased potential of enhanced rainfall due to thunderstorms. Additionally, although there is ample uncertainty associated with this disturbance, heavy precipitation, high winds, and other adverse impacts to Hawaii cannot be ruled out during week-2, with both the GEFS and ECMWF PETS depicting at least a 20 percent chance of 3-day precipitation values exceeding the 85th climatological percentile across the state. In the Atlantic, Tropical Storm Dolly has opened up into a wave. There is some potential albeit fairly low for some redevelopment during the next few days as this system reaches the southeastern Gulf of America. While unlikely to be a significant system, there could be periods of local enhanced rainfall across parts of Florida and the Southeast lingering from the end of week-1 into the start of week-2, although much of it seems to likely time out prior to this period. Enhanced onshore flow may bring periods of heavy precipitation and gusty winds across southern Alaska late in week-1 into the start of week-2, with much of the impacts anticipated to time out by week-2. Snow cannot be ruled out across portions of the Brooks Range and the higher elevations of southeastern Alaska. FORECASTER: Melissa Ou $$