376 FXUS21 KWNC 151744 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT May 15 2026 SYNOPSIS: Mid-level low pressure is anticipated to shift eastward from the Northeastern Pacific to the West Coast by the middle of week-2. Surface low pressure is expected to develop ahead of this mid-level low pressure across the central contiguous U.S. (CONUS). This low pressure combined with enhanced moist southerly flow from the Gulf increases the likelihood for heavy precipitation across parts of the Southern Plains into the Southeastern U.S. from the end of week-1 into Memorial Day weekend. Surface lows across the Interior West may support episodes of high winds for parts of this region and the Great Plains. HAZARDS Moderate risk of heavy precipitation for the Southern Plains, Lower Mississippi Valley, and Southeastern U.S., Sat-Sun, May 23-24. Slight risk of heavy precipitation for portions of the Southern Plains, Lower Mississippi and Tennessee Valleys, and Southeastern U.S., Sat-Mon, May 23-25. Slight risk of high winds for portions of the Interior West and the Great Plains, Mon-Wed, May 25-27. DETAILED SUMMARY FOR MONDAY MAY 18 - FRIDAY MAY 22: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR SATURDAY MAY 23 - FRIDAY MAY 29: Multiple model ensemble means indicate mid-level ridging across much of the country except for troughing across the West Coast for the week-2 period. Above normal temperatures are favored across much of the CONUS except for the West Coast, southern Four Corners region into western Texas which is forecast to have near normal temperatures. The Probabilistic Extremes Tools (PETs) indicate temperatures exceeding the 85th percentile climatologically periodically across much of the interior portions of the CONUS, however not reaching or exceeding hazardous criteria at this time. Mid-level troughing with the trough axis centered across the West Coast is predicted to continue from the end of week-1 into and through week-2. A series of surface lows and trailing fronts are expected ahead of this trough over the central CONUS. This pattern combined with enhanced southerly moist flow from the Gulf increases the chances for heavy rainfall across parts of the south-central and southeastern CONUS during Memorial Day weekend. A moderate risk of heavy precipitation is designated for parts of the Southern Plains, Lower Mississippi Valley, and Southeastern U.S., May 23-24, where the ECENS (GEFS) indicate at least a 40% (30%) chance of 3-day rainfall exceeding one inch, with uncalibrated guidance showing higher probabilities. A broader area is highlighted across portions of the Southern Plains, Lower Mississippi and Tennessee Valleys, and Southeastern U.S. with a slight risk (20-40% chance) of heavy precipitation, May 23-25. Conditions may be conducive to thunderstorms across the Great Plains and Mississippi Valley. Given the prevailing drought conditions for many areas across the South, these rains may prove beneficial. However, isolated flash and urban flooding is possible. Additionally wet conditions during week-1 may elevate rivers in portions of the region, enhancing the potential for localized river flooding especially in east Texas and adjacent areas. The slight risk for high winds across coastal portions of the West Coast is discontinued in todays outlook due to timing out. Ahead of the mid-level trough across the West Coast, surface lows are predicted to form across the Interior West and in the lee of the Rockies, supporting a slight risk of high winds for these areas for the middle of week-2 (May 25-27), as the pattern becomes more favorable for this hazard. The PETs show at least a 20% chance of wind speeds exceeding the 85th percentile, with uncalibrated ensemble guidance showing enhanced probabilities of wind gusts exceeding 34 kts (~ 40 mph) in the highlighted risk area. In Alaska, river ice breakup season is now underway, 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: Melissa Ou $$