432 FXUS02 KWBC 251710 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 110 PM EDT Mon May 25 2026 Valid 12Z Thu May 28 2026 - 12Z Mon Jun 01 2026 ...Heavy rain and thunderstorms expected to continue across much of the Southern U.S... ...Overview... Multiple pieces of energy within a southern stream shortwave will pass through the south-central U.S. later this week, providing lift for widespread rain and thunderstorms in a moist and unstable environment stretching through the Southeast as well. Heavy rain is likely to focus more into the Middle to Lower Mississippi Valley midweek, potentially over areas that will already have wet antecedent conditions, leading to some concern for flooding. Out West, a closed upper low should be atop the Great Basin mid to late week, resulting in cooler temperatures and precipitation for the West as it meanders while weakening. A blocky upper ridge is set to stretch across the north- central U.S. and bring above average temperatures through much of the period. Meanwhile a couple of upper troughs/lows should push through the Northeast and allow for precipitation chances. ...Guidance/Predictability Assessment... Overall good model agreement continues for the large-scale dynamics through the period with the closed upper low over western U.S. and troughing over northeast U.S., while a blocking pattern becomes more defined by the end of the week. The differences amongst the models arise with the small scale features, especially across the southern tier with a shortwave energy moving eastward, which can affect sensible weather. Heading into the weekend, a southern stream energy ejects across the south- central U.S. CMC shows some differences compared to the GFS and ECMWF in respect to the location of the trough, but the ensemble means solution tends to smooth out some of the amplitude and timing differences. The WPC forecast utilizes a blend of ECMWF/CMC/GFS/EC- AIFS/UKMET for the first portion of the period, with incorporating more weight on a blend of the the ensemble means to account for the small scale differences towards the latter half of the period. ...Weather/Hazards Highlights... Persistent southern stream energy will continue to keep much of the South active and unsettled into the weekend within a very moist and unstable environment and daily thunderstorm chances. Both the Day 4/Thursday and Day 5/Friday EROs show broad Marginal Risks across the middle-lower Mississippi Valley and into parts of the Tennessee Valley and Deep South where moisture anomalies are high with sufficient instability. Models continue to show some uncertainty with the placement of the moisture, which will impact where the heaviest QPF may focus, but future Slight Risk will not be out of the question. Wet weather is likely across the Southeast into Florida as well, with a Marginal Risk for parts of southern Florida Thursday and Friday in a favorable pattern for heavy rainfall. After what has been a very wet period for much of Texas, conditions should finally settle across the region later this week as the overall pattern shifts slightly east. However, rainfall may be renewed again across Texas by the weekend. Upper troughing 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 across higher elevations, with highest amounts now most likely in the Sierra Nevada. Combining energies will allow rain chances to stretch east into the central Plains and Midwest for midweek and beyond. Rainfall is also possible across the Northeast underneath the upper low. With the closed upper low over the West, temperatures should be below normal through about Friday, with some moderating back towards normal as the trough weakens and drifts next weekend. 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 mid to late week. Renewed troughing over the East may bring slightly below normal temperatures there as well. Oudit/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 $$