399 FXUS21 KWNC 051805 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT May 05 2026 SYNOPSIS: Amplified mid-level high pressure is forecast across the western contiguous U.S. (CONUS) late in week-1. By the start of the week-2 period, this feature is predicted to weaken and shift eastward toward the south-central CONUS. This results in relatively lower chances for extreme heat across the Southwest compared to yesterday, but with increasing heat concerns across the Southern Plains, particularly over parts of northwestern Texas into Oklahoma where record breaking temperatures for this time of year are possible. Conversely, persistent mid-level low pressure across the Great Lakes and Northeast favors anomalously cool weather across the region at the outset of the period. HAZARDS Moderate risk of extreme heat across northwestern Texas into Oklahoma, Wed-Thu, May 13-14. Slight risk of extreme heat across portions of the Southern Plains extending into southern Kansas, Wed-Fri, May 13-15. Slight risk of extreme heat across portions of the southwestern CONUS and the California Central Valley, Wed-Fri, May 13-15. Slight risk of much below normal temperatures across portions of the Great Lakes, Ohio Valley, Appalachians, and Northeast, Wed, May 13. Slight risk of high winds across portions of the Central and Southern Plains, Wed-Thu, May 13-14. Slight risk of high winds across the northern coast of California and coastal Oregon, Wed-Fri, May 13-15. DETAILED SUMMARY FOR FRIDAY MAY 08 - TUESDAY MAY 12: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR WEDNESDAY MAY 13 - TUESDAY MAY 19: The 0z ECMWF, GEFS, and Canadian ensembles depict a strong mid-level ridge (+120 meter positive height anomaly) over the western CONUS late in week-1. By the outset of week-2, this ridge is forecast to weaken and shift farther eastward into the south-central CONUS. This favors the greatest heat risk potential also shifting from the Southwest to the Southern Plains. As a result, the moderate risks of extreme heat are discontinued across the California Central Valley and Desert Southwest, with a slight risk continuing through May 15 as high temperatures may still reach the upper 90s deg F to over 100 deg F, but would be relatively cooler compared to prior days. The National Blend of Models (NBM) and uncalibrated dynamical models now depict the potential for record daily high temperatures across northwestern Texas into western and central Oklahoma and southern Kansas. The hottest areas may see highs in the upper 90s to near 100 deg F, with indications of record heat beginning prior to the start of the period. The GEFS and ECMWF Probabilistic Extremes Tools (PETs) depict at least a 40 percent chance maximum temperatures exceed the 85th climatological percentile across portions of the Central and Southern Plains early in the period, and skill weighted calibrated heat risk guidance also indicates probabilities of 40-60 percent for heat to exceed the 90th climatological percentile. A moderate risk of extreme heat is posted across northwestern Texas into parts of Oklahoma May 13-14 where there is the greatest potential for temperatures above 95 deg F. The slight risk is valid through May 15, and is extended farther north into southern Kansas where temperatures may reach 90 deg F. Elevated heat risk signals also support an extension of the slight risk into the Rio Grande Valley due to enhanced moisture and potential for elevated heat index values. The anomalous warmth forecast across the West favors thermal low development and an increased pressure gradient along parts of the West Coast. The uncalibrated 0z GEFS and ECMWF ensembles both show enhanced probabilities for wind speeds above 25-mph across coastal portions of northern California and Oregon early in week-2, and this signal is also apparent in the PETs. Therefore, a slight risk of high winds is posted across these areas, May 13-15. Models also depict elevated chances for gusty winds across the south-central CONUS, and this is particularly concerning given the extreme heat potential combined with dry soils contributing to an enhanced wildfire threat. This supports a slight risk of high winds across portions of the Central and Southern Plains, May 13-14. A persistent trough linked to the negative phase of the North Atlantic Oscillation (-NAO) remains forecast across the Great Lakes and Northeast at the start of week-2. This continues to favor below-normal temperatures across the region. Despite it getting later into May, the ECMWF and GEFS PETs depict parts of the Ohio Valley, Great Lakes, Appalachians, and Northeast having at least a 20 percent chance minimum temperatures fall below the 15th climatological percentile and 40 deg F on day-8 (May 13). Late season frosts still cannot be ruled out across more northern and higher elevation areas, and the slight risk for much below normal temperatures remains in place, May 13. A more southerly component to the surface flow combined with a warming climatology favors increasing temperatures thereafter. As a result of the more southerly flow pattern emerging, the 0z ECMWF ensemble depicts enhanced precipitation chances across the east-central CONUS early in the period, with its corresponding PET showing a fairly broad area with at least 20 percent chances for 3-day precipitation totals to exceed the 85th climatological percentile and 1-inch extending from the Gulf Coast north to the Middle Mississippi and Ohio Valleys. However, support from the GEFS is limited, and given the model uncertainty no related precipitation hazard is issued. This will continue to be monitored, but this surface evolution would reduce any risk for hazardous cold temperatures across the Ohio Valley and Northeast. Over the Alaska region, surface low pressure across the Bering Sea favors increased southerly flow and occasional enhanced precipitation and gusty winds along the southern and southeast coasts. However, hazards criteria are not anticipated to be reached. Troughing favors generally near- to slightly below-normal temperatures over most of the state, excluding the northwestern Mainland where there are elevated chances for above-normal temperatures. The typical peak of the river ice breakup season is approaching, and ice jam flooding can occur this time of year with little or no notice as conditions on frozen rivers can change quickly. Please check with the Alaska Pacific River Forecast Center for the latest conditions and advisories. FORECASTER: Thomas Collow $$