100 FXUS02 KWBC 201953 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 253 PM EST Thu Nov 20 2025 Valid 12Z Sun Nov 23 2025 - 12Z Thu Nov 27 2025 ...Heavy Rain Threat for the Southern Plains and Lower Mississippi Valley on Sunday and Monday... ...Overview... A strong closed upper low will move across the Southwest this weekend and into the south-Central U.S. early next week. Southerly flow ahead of the low will bring warm, moist air into the southern Plains and Lower Mississippi Valley, which will support a heavy rain threat across these regions on Sunday and Monday. The system will continue to move east-northeast on Tuesday, expanding moderate precipitation chances into the Ohio and Tennessee Valleys, Mid-Atlantic, and Northeast. Meanwhile, a couple of upper level troughs will swing across the northern tier of the nation in more progressive flow, resulting in periods of precipitation from the Northwest to the Northeast, with heavy snow potential in the higher elevations of the Cascades and northern Rockies. ...Guidance/Predictability Assessment... Models continue to show good agreement on the overall synoptic scale pattern through the medium range period. There are still some differences in the details of individual systems, mainly in the second half of the period. The most uncertainty surrounds the evolution of a low pressure system moving across the Great lakes and Northeast mid-to-late next week and the timing of a trough approaching the Northwest, both of which will affect precipitation amounts and location. Given good agreement, a near even blend of the latest runs of the deterministic GFS/ECMWF/CMC/UKMET provided a good starting point for the afternoon forecast. Ensemble means from the GEFS/ECENS/CMCE were added in increasing amounts through the second half of the period to help smooth out model differences. ...Weather/Hazards Highlights... A low pressure system will bring widespread light to moderate precipitation to the Southwest this weekend, then the system will push into the south-Central U.S. early next week. Warm, moist air will support a heavy rainfall threat across the southern Plains and Lower Mississippi Valley Sunday into Monday, and there are signals that this may be a significant event. There is a Slight Risk of excessive rainfall for the southern Plains on Sunday and into the Lower Mississippi Valley on Monday. This system will track east-northeast, spreading precipitation to the east-Central and eastern U.S. through Tuesday. Periods of precipitation will also be possible across the northern tier of the nation as a low pressure system tracks along the U.S./Canada border. This system will likely also bring gusty winds to the northern/central Rockies and Plains early next week. Another round of precipitation is forecast across the Northwest mid-week as an upper trough pushes onshore from the Pacific, and there will be potential for heavy snow in the higher elevations of the Cascades and northern Rockies. Pre-frontal temperatures will be warmer than average for much of the Central and eastern U.S. this weekend into early next week. Much above average temperatures are forecast for the South and Southeast this weekend where a handful of record high temperatures will be possible. Meanwhile, California and the West/Southwest will see below average highs underneath the closed upper low. Mid- next week, below normal temperatures will also spread across the Central U.S. in the wake of a strong cold frontal passage. Dolan/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 (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 $$