631 FXUS02 KWBC 160755 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 355 AM EDT Sat May 16 2026 Valid 12Z Tue May 19 2026 - 12Z Sat May 23 2026 ***Multiple rounds of heavy rain and severe storms expected for the southern Plains, and early season heatwave for the East Coast*** ...General Overview... An amplified upper level pattern will be in place for the beginning of next week, with an anomalous ridge over the east-central U.S. supporting an early season heat wave, and a strong trough over the Rockies that will bring a round of late season snow for the higher elevations of Colorado and Wyoming. At the interface of these two features will be broad diffluent flow over a strong cold front that will cross the Plains and Midwest, bringing multiple rounds of heavy rainfall and strong/severe thunderstorms. ...Guidance/Predictability Assessment... The deterministic model guidance suite features decent overall agreement for the beginning of the period Tuesday, and a general model compromise works as a starting point for fronts and pressures. Model differences become most noticeable across the Western U.S. and northern Plains with the next trough building into the region. The overall flow pattern becomes more zonal going into next weekend with more uncertainties with shortwaves in the northern stream flow. The ensemble means were increased to about half by Saturday as deterministic model spread increases. ...Weather/Hazards Highlights... A dynamic storm system crossing the Plains will bring widespread showers and thunderstorms from Texas to the Ohio Valley ahead of a strong cold front. On Tuesday, the best focus for heavy rainfall is expected to be across Texas and extending eastward to Arkansas and the Mid-South as the front intercepts deeper moisture and slows down in its forward progress. A Slight Risk of excessive rainfall is valid from eastern Oklahoma to the Ozarks for the Day 4 outlook where the best potential for repeated rounds of heavy convection is expected to exist. Additional heavy rainfall is likely going into Day 5/Wednesday with a broad Marginal Risk extending from western Texas to the central Appalachians. In the temperature department, heat will be making headlines for much of the Eastern U.S. through the middle of the week, with the hottest conditions across interior portions of the Mid-Atlantic into the Carolinas where highs are likely to reach the lower to middle 90s. This will likely be warm enough to establish some daily record highs before a cold front brings relief from the Ohio Valley to the Mid-Atlantic/Northeast by Thursday. The opposite will hold true for the Intermountain West and Rockies with below normal readings to start the week, and snow for the higher elevations, followed by a moderation trend. Hamrick Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation forecast, excessive rainfall outlook, winter weather outlook probabilities, heat indices and Key Messages are at: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml https://www.wpc.ncep.noaa.gov/#page=ovw $$