232 FXUS02 KWBC 231922 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 322 PM EDT Sat May 23 2026 Valid 12Z Tue May 26 2026 - 12Z Sat May 30 2026 ...Heavy rain and thunderstorms expected to continue across much of the Southern U.S... ...Overview... A couple of upper level shortwaves and pieces of energy will pass through the south-central U.S. next week, providing lift for widespread rain and thunderstorms in a moist and unstable environment. The heaviest rain looks to focus in parts of Texas and the Lower Mississippi Valley, potentially over areas that will already have wet antecedent conditions. Out West, a more amplified pattern starts to emerge as a closed low enters the Pacific Northwest and envelops more of the Intermountain West by mid to late week, yielding cooler temperatures and precipitation. An upper ridge should develop downstream in the east-central U.S., reaching into the Upper Midwest/Great Lakes and bringing above average temperatures. ...Guidance/Predictability Assessment... Recent model agreement has become rather good for the upper low diving from the Pacific Northwest Tuesday south through the Great Basin Wednesday and Thursday. The low is likely to linger late week and slowly weaken as it lifts northeast into Saturday. A 12Z model composite should work well with that feature, after the 00Z GFS was the main outlier in showing the low shunting east to the central High Plains, but the 06Z and 12Z GFS runs have trended much closer to consensus. To the east, upper ridging will stretch from the Southeast northwestward into the Midwest as southern stream energy cuts into it in the south-central U.S., with typical model differences in the details. As the southern energy weakens and moves east, the ridge looks to reform with a neutral tilt across the Plains late week into the weekend. The pattern starts to look more like an omega block as troughing retrogrades into the Northeast. After quite a bit of spread in the 00/06Z runs with that Northeast trough, including the EC/CMC more progressive and the GFS farther west, the 12Z guidance is generally showing a better middle ground forecast that is more like the ensemble means and AIFS. With increasing consensus in the models, used a multi-model blend for the forecast period, with some inclusion of the ensemble means for the latter part of the period to mitigate individual model differences. ...Weather/Hazards Highlights... Rounds of persistent southern stream energy will continue to keep much of the Southern Plains to the Southeast active and unsettled well into next week within a very moist and unstable environment and daily thunderstorm chances. This could be especially impactful for parts of Texas and the Lower Mississippi Valley where recent rains and additional rain in the short term has lead to rather saturated grounds. For the Days 4 and 5 EROs, broad Marginal Risks are in place across much of the Southern U.S., and continue to highlight embedded Slight Risks for portions of Texas on Day 4/Tuesday and southeast Texas to western Louisiana on Day 5/Wednesday. The exact locations of heavier rainfall will likely change as models come into better agreement, but the pattern overall favors heavy rainfall potential with flooding an increasing concern given the potentially concerning antecedent conditions. The wet pattern will continue along the Gulf Coast into the Southeast and Florida through the rest of the week into next weekend, but may gradually calm down over Texas. Upper troughing across the Northwest and meandering around the Great Basin with a frontal system ahead of it will allow for increased precipitation across the Pacific Northwest to Intermountain West for multiple days. Snow is possible at the highest elevations of the Cascades to Rockies. Combining energies will allow rain chances to stretch east into the central Plains and Midwest for midweek and beyond. With the closed upper low over the West, temperatures should trend cooler in this region through about Wednesday, with some moderating back towards normal as the trough weakens and drifts. The upper ridge to its east will allow for warmer than average temperatures across the north-central U.S. through much of next week, with daytime highs 10-20 degrees above normal, with greatest anomalies through around midweek. Tate/Santorelli 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 $$