093 FXUS02 KWBC 220647 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 247 AM EDT Fri May 22 2026 Valid 12Z Mon May 25 2026 - 12Z Fri May 29 2026 ...Heavy rain and thunderstorms expected to continue across much of the Southern U.S... ...Overview... A couple of southern stream upper troughs will pass through the southwestern and south-central U.S. next week, providing lift for widespread rain and thunderstorms in a moist and unstable environment. The heaviest rain should generally affect the Lower Mississippi Valley and Southeast into Monday, and potentially get renewed in Texas and vicinity into the workweek over areas that will already have wet antecedent conditions. A shortwave over the Great Lakes should reach northern New England by Monday night, with widespread showers from the Ohio Valley to the Northeast ahead of this feature. Out West, a more amplified pattern starts to emerge as a stronger upper trough likely becoming a closed low enters the Pacific Northwest and envelops more of the Intermountain West by the middle of the 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... The latest models and guidance show good agreement on the overall pattern evolution through the period, which should gradually trend more and more amplified through next week. There was good enough agreement both with the Northeast shortwave and a series of shortwaves across the South for a general model blend to serve as the starting point for the WPC prog charts. The main (and most impactful) source of uncertainty continues to be with an upper low that enters the Pacific Northwest around Tuesday, deepens/shifts south through Thursday, then should start to shift eastward. The better consensus of guidance (supported by the ECMWF, EC-AIFS, CMC, and ECENS mean) suggests this general pattern, and the latest 00z run of the GFS tonight has trended towards this as well. The WPC progs/sensible weather grids leans heavier on these deeper/slower solutions, consistent with continuity. A general trend now towards this seems to increase confidence a bit. ...Weather/Hazards Highlights... The northern stream trough over the Northeast will allow for scattered showers along a frontal boundary from the lower Ohio Valley into the Mid- Atlantic and Northeast on Monday. Convection also looks to spark in the Four Corners region on Monday in response to a southern stream shortwave. This system looks to renew heavy rain potential in Texas and vicinity and through much of the Southern U.S./Southeast through next week. For now, just broad marginal risks on the Day 4/Monday and Day 5/Tuesday EROs should suffice, but it's possible a slight risk may be needed as models converge on better potential for where heavy rainfall may occur. This is especially true for parts of Texas and vicinity (Tuesday and beyond) where recent rains and short term rainfall has lead to rather saturated grounds. Upper troughing moving into the Northwest early next week and a frontal system ahead of it will allow for increased precipitation reaching the Pacific Northwest and spreading south and eastward with time through the week. Snow is possible at the highest elevations of the Cascades to Rockies. With a deepening trough over the West, temperatures should trend cooler in this region through about Wednesday, with some moderating back towards normal as the trough starts to press eastward. 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, especially for the early part of the week. 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 $$