082 FXUS02 KWBC 261955 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 355 PM EDT Tue May 26 2026 Valid 12Z Fri May 29 2026 - 12Z Tue Jun 02 2026 ...Heavy rain/thunderstorms for parts of the Southern U.S... ...Overview... A blocky upper flow pattern with embedded shortwave energies affecting portions down through the Southern to Southeast U.S. through this forecast period in two streams will continue to bring periods with widespread rain and thunderstorms within a moist and unstable environment. Heavy rain is possible, and given how wet a lot of this region has been lately and will be in the short range as well, flooding could be a concern in some places. Out West, a closed upper low over the central Great Basin Friday should lift northeastward and weaken intothe weekend as another shortwave slides through the Pacific Northwest later in the period. This should result in precipitation chances for the Intermountain West/Northern Rockies, with lead forcing/activity over the Plains. Reinforcing troughing over the Northeast should result in near to below normal temperatures and precipitation chances. Meanwhile, in between, a blocky ridge will bring pre-frontal above normal temperatures to much of the north-central U.S. through the period. ...Guidance/Predictability Assessment... Models show good agreement on the overall large scale pattern evolution through the period, but with much in the way of smaller scale local focus and guidance differences to decipher through the forecast period, but especially later in the period. Some increasing uncertainty by early next week across the Northwest regarding the evolution as the initial upper low weakens and another shortwave moves into the region. There is question on how quickly this pushes out of the region and how strong ridging is across the region early next week. A lot of this seems to be related to a large upper low across the northeast Pacific. There remains uncertainty in the Northeast too with various waves of energy moving through the Great Lakes to reinforce a mean trough over much of the East through the period. This also impacts the structure and strength of a mean ridge over the north-central U.S.. For the most part, a blend of the models and ensemble means seemed to work out well to mitigate these differences as consistent with individual predictability. This solution is generally in line with the NBM and WPC product continuity, but as per the National Hurricane Center continues to discount tropical moisture feed and development potential by recent GFS runs over/from the Caribbean. ...Weather/Hazards Highlights... It generally remains the case that persistent shortwave energies and a couple of wavy frontal boundaries 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. Combined with what has already been a wet pattern across this region, flooding is a concern. For Day 4/Friday, a broad Marginal Risk is in place on the ERO from the lower/middle Mississippi Valley to the Southeast. For Saturday, the heaviest rain should focus along a frontal boundary sinking through the Southeast, where a Marginal Risk is in place on the ERO. Moisture and precipitation looks to renew across Texas by the weekend as well, and a Marginal Risk was introduced for that region on Day 5. Florida will remain within a wet pattern, aided by tropical moisture. Marginal Risks are in place both Friday and Saturday for what should be mainly a urban flash flood threat. Precipitation across the South will continue into early next week, but should shift southward with time as the trough over the East deepens, though continuing back across Texas and the southern Plains. To the north over the Northeast, a vigorous vort moving through late this week may result in a period of moderate to heavier rainfall from parts of New England given windy offshore low genesis, with light amounts southward to the central Appalachians. Out west...upper troughing meandering around the Great Basin with a wavy frontal system ahead of it will allow for increased precipitation across the Intermountain West for the end of this week. Snow is possible across the highest elevations, though with minimal accumulation. As the upper low weakens and shifts northeast, rain chances should increase into the north-central Rockies/Plains. 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. Ridging building back into the region late in the period may bring values slightly above average. 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. Persistent troughing over the East may bring slightly below normal temperatures through the period. Santorelli/Schichtel 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 $$