797 FXUS02 KWBC 062000 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EST Tue Jan 6 2026 Valid 12Z Fri Jan 09 2026 - 12Z Tue Jan 13 2026 ...Tennessee Valley to Southern Appalachians Heavy Rain threat focus on Friday... ...Overview... Deep upper troughing digging through the Western U.S./Rockies and through south-central Canada Friday will gradually progress eastward and phase over the weekend with deepended low formation near a stormy Great Lakes region. This will promote moderate to heavy precipitation chances along and ahead of the associated frontal boundary across the eastern third of the country. Wintry precipitation including a swath of heavy snow is expected on the wrap-back side of the system/main low into the Upper Midwest and Great Lakes where enhanced Lake Effect activity will flourish in the cold wake of system passage. Ahead of this front, record high pre-frontal temperatures are expected into Friday/Saturday for portions of the east-central to eastern states. Once the front clears the East Coast this weekend, much of the country will be dry Sunday into early next week underneath sprawling high pressure, but expect renewed rainfall to the Pacific Northwest and perhaps Texas. ...Guidance/Predictability Assessment... Guidance solutions are reasonably well clustered for Friday/Saturday despite local weather focus variances seemingly best mitigated by a GFS/ECMWF/Canadian model composite in an active pattern with average to better predictability. Favor a transition Sunday to a GEFS/ECMWF/Canadian ensemble mean blend through longer time frames amid quickly growing forecast spread and uncertainties. Recent model runs have been offering way less than stellar cycle to cycle continuity with the handling and phasing of multi-stream system energies digging into the west-central to eastern U.S. compared to more consistent yet still uncertain ensemble mean guidance. Latest 12 UTC model guidance, especially the ECMWF, continues to show significant to wild run-run changes, now with a progressive trend. ...Weather/Hazards Highlights... Ample Gulf moisture (with highly anomalous values above the 95th percentile) will stream ahead of the Central U.S. trough to produce widespread rain from the Gulf Coast to the Ohio Valley, Mid- Atlantic, and Northeast Friday into Saturday. Models are showing an increasing signal for heavy to excessive rainfall potential, particularly Friday across portions of the Tennessee Valley and into the southern Appalachians. Given the anomalous moisture and some instability (especially south) went ahead with a slight risk upgrade for the Day 4/Friday ERO period from northeast Mississippi to central Tennessee where model 24-hour QPFs show support for 2-4+ inches of rain and some potential for training along the initially slow to move boundary. By Saturday, the precipitation moves into the East and the frontal boundary should be progressive enough by that time to preclude a risk area on the Day 5 ERO at this time. Precipitation should clear the coast by Sunday, with some possible showers lingering across Florida. On the cold side of this system, there is the potential for accumulating snow from the Central Plains to the Upper Midwest and northern Great Lakes Friday into Saturday. The signal is growing for a swath of wrap-back heavy snow and blowing winds over the Upper Midwest and Great Lakes. Lake effect snows will continue into Sunday downwind of favorable locations. After this though, much of the country by early next week will be dry with the exception of western Washington in favorable deep layered southerly flow nudging into the region and possibly parts of the Southern Plains contingent on induced return flow by southern stream trough energy. Temperatures are likely to be well above average across the eastern third of the country Friday into Saturday ahead of the big trough, with temperature anomalies of 15 to 25 degrees above normal. Daily records for warm lows and highs could be set across the southern tier and into parts of the Mid-Atlantic. Temperatures will return to normal from west to east following the frontal passage. Meanwhile the West/Southwest may start below normal but should trend warmer with time as a ridge develops over much of the region. This ridge will also build into the north-central U.S. this weekend with the return of above to well above normal temperatures. 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 (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 $$