FXUS02 KWBC 050659 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 259 AM EDT Thu Jun 5 2025 Valid 12Z Sun Jun 08 2025 - 12Z Thu Jun 12 2025 ...Severe weather possible in the southern through the weekend, with heavy rain possible there through much of next week... ...Heat wave for the Interior West with some heat in South Texas... ...Overview... Multiple rounds of thunderstorms that may be severe and/or cause flash flooding in the southern tier in particular as expected to accompany fronts pushing through the Plains eastward. Meanwhile, rounds of ridging over the West (though interrupted by shortwaves) will lead to much above normal temperatures. ...Guidance/Predictability Assessment... The latest suite of guidance continued to show agreement of the large scale features yet wavered on details. Consolidated energy diving across south-central Canada will form an upper low by Sunday that reaches the Upper Midwest/Great Lakes on Monday and deepens the trough slightly across the east- central U.S. The timing and strength of shortwave energy and associated surface fronts remain uncertain. Within general spread, the GFS continues to depict a relatively deep surface low atop Ohio/Pennsylvania by early Sunday and higher QPF than the rest of the cluster. Consensus persists for this trough axis to start moving more quickly east by midweek. The northern stream upper ridging to be atop the Northwest over the weekend, expanding and moving east across the Intermountain West gradually next week as a trough may reach the West Coast by Tuesday or Wednesday. A southern stream low offshore California to start the period on Saturday looks to shrink/weaken but perhaps drift inland early next week, with more uncertainty. The preferred WPC blend utilized 18Z GFS and 12Z ECMWF/CMC/UKMET as a starting point and then included modest weighting of the EC ensemble and GEFS mean beyond the weekend ...Weather/Hazards Highlights... Showers and thunderstorms may continue to linger across the Northeast while the front pulls further offshore Sunday. However convection will continue along front that stretches through the Lower Ohio/Tennessee Valleys, Lower Mississippi Valley, and into the Southern Plains. Greater rainfall rates and accumulations are likely to focus over portions of Oklahoma and Texas where there will be pooled Gulf moisture and high instability to tap into and recent heavy rains. The Storm Prediction Center continues to show the potential for severe weather across the South/Central Plains east into the Southeast. WPC maintained the broad Marginal Risk from the Texas Panhandle to the Southeast Coast with an embedded Slight along the Red River into the Ark-La-Tex. The front will advance southward by Monday and the precipitation will be widespread across the Gulf states, Lower Mississippi Valley, and eastern parts of the Southern Plains. WPC raised a broad Marginal Risk that stretches from eastern New Mexico to western Georgia. Given the variances on the location of the highest QPF opted to keep the threat potential as a level 1 although there are signal for local 2 to 4 inches which may require a future upgrade to a Slight should agreement improve. Meanwhile, another frontal system will track across the Midwest/Great Lakes for some modest rain there over the weekend, reaching the Northeast by Monday and Tuesday. The current forecast continues to show the leading front dissipating while this secondary front becomes dominant. The second front settling south will once again promote rain and thunderstorms across the southern Plains and Southeast through the first half of next week as the moisture and instability lingers. Temperatures are expected to be near to slightly below seasonal average for central and eastern portions of the country with the troughing. For southern Texas daily readings will climb well into the 100s with heat indices possibly above 110F. But the largest temperature anomalies will be across the Northwest U.S. through the weekend into early next week underneath mean upper ridging. This region will observe readings 15 to 25 degrees warmer than average for early June, with some interior locations hitting the 90s. Even cities like Seattle look to reach the mid to upper 80s. Above normal temperatures will stretch into the central Great Basin, and the Desert Southwest can expect temperatures well into the 100s to 110 degrees. For safety information, see weather.gov/heat. Campbell/Tate 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 (QPF), excessive rainfall outlook (ERO), winter weather outlook (WWO) probabilities, heat indices, and Key Messages can be accessed from: 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 $$