213 FXUS21 KWNC 021806 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT May 02 2025 SYNOPSIS: Early in week-2, a slow-moving low pressure system is forecast to bring an increased chance of heavy precipitation to the Southeast. Following a very wet April and beginning of May, a brief period of drier weather is expected throughout the Southern Great Plains from May 10-13. However, later in week-2 (May 14-16), a stormy pattern may return. Mid-level high pressure favors above-normal temperatures across the Northern and Central Great Plains along with the Corn Belt. HAZARDS Slight risk of heavy precipitation for parts of the Southeast, Sat-Mon, May 10-12. DETAILED SUMMARY FOR MONDAY MAY 05 - FRIDAY MAY 09: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR SATURDAY MAY 10 - FRIDAY MAY 16: During early to mid-May, model guidance remains consistent that a blocky pattern prevails over the lower 48 states. To the south of a broad mid-level ridge across the northern tier of the contiguous U.S. (CONUS), a 500-hPa shortwave trough is forecast to advance slowly eastward across the Southeast from late week-1 to early week-2. Ensemble mean solutions from the GFS, ECMWF, and CMC models are in better agreement today and favor multiple days with an elevated chance of heavy precipitation for this region. Based on the 24-hour precipitation amounts from these ensemble means, a slight risk of heavy precipitation (20-40 percent chance of more than 1 inch) is posted for portions of the Southeast from May 10 to 12. Any slow-moving or training thunderstorms could be capable of producing locally heavier amounts with an associated flash flooding risk. This wetter pattern would alleviate short-term dryness for southeast Alabama, south Georgia, the Florida Panhandle, and Carolinas where 30-day deficits exceed 2 inches. Multi-model ensemble mean solutions indicate a 500-hPa trough shifting inland into the West towards the end of week-2, May 16. If this were to occur, there would be a renewed risk of thunderstorms with locally heavy rainfall across the Great Plains. In addition, mesoscale convective systems with heavy precipitation become more common by mid-May. No precipitation hazards are posted for the central U.S. at this time but the evolving pattern will be closely monitored in subsequent outlooks. An amplified 500-hPa ridge, centered over the Northern Great Plains, strongly favors above-normal temperatures across the north-central CONUS. Although the ECENS Probabilistic Extremes Tool depicts that there is more than a 50 percent chance of maximum temperatures exceeding the 85th percentile across the Dakotas, no heat hazards are posted with maximum temperatures expected to remain below 90 degrees F. The GEFS, ECENS, and CMCE feature a weak 500-hPa trough persisting over Alaska through mid-May. Although this trough aloft would promote periods of enhanced precipitation at times, no hazardous precipitation is anticipated. As temperatures warm this month, river ice breakup will continue which could lead to ice jams and flooding. FORECASTER: Brad Pugh $$