Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
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880 FXUS02 KWBC 070651 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 151 AM EST Wed Jan 7 2026 Valid 12Z Sat Jan 10 2026 - 12Z Wed Jan 14 2026 ...Overview... A closed low and deep trough will progress through the eastern half of the country, with an associated deepening low pressure system across the Great Lakes and a strong cold front into the East. Moderate to locally heavy rainfall is possible along the frontal boundary on Saturday, with moderate snow fall possible on the backside of the low from the Upper Midwest into the Great Lakes where enhanced lake effect activity will also flourish in the cold wake of system passage. Ahead of the front, record temperatures are possible into Saturday for much of the East. Once the front clears the East Coast this weekend, much of the country will be dry Sunday into next week underneath sprawling high pressure, but expect renewed rainfall to the Pacific Northwest. ...Guidance/Predictability Assessment... The latest guidance shows good agreement on the overall large scale pattern evolution across the country, but plenty of uncertainty in the details and timing of individual systems. Some minor timing differences continue with the main system this weekend into the East, which impacts surface low deepening, and front/QPF timing. The GFS was a bit deeper with the trough overall, which makes it a bit slower to exit the East Coast. Additional southern stream energy looks to cut off from this deep trough moving into Texas as it weakens next week. Models then show another shortwave or two into the north-central U.S. early next week which should renew deep troughing across the east-central states by next Wednesday. There is uncertainty in the smaller scale energies that progress through this trough. This overall deepening trough though should allow for a building ridge over the West Coast states. The WPC forecast for tonight was based on a general deterministic model blend for Day 3-5/Saturday-Monday amidst good enough agreement. Increased weighting of the ensemble means the latter half of the period to help mitigate some of the late period differences. ...Weather/Hazards Highlights... Ample Gulf moisture (with highly anomalous values above the 95th percentile) will stream ahead of the central to eastern U.S. trough to produce widespread rain ahead of a strong frontal boundary as it pushes through the Ohio Valley/Appalachians and East Coast states on Saturday. Moderate to locally heavy rainfall is possible but the front should be progressive enough, with drier antecedent conditions, to preclude any risk areas 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 signal is growing for accumulating snow from the Upper Midwest to the northern Great Lakes into Saturday with 4+ inches of snow possible in some locations. 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 will be well above average through Saturday across the eastern states with record daytime highs and warm overnight lows possible. Temperatures will return to normal following the frontal passage and may be slightly below normal for some places. 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. and expand across the Plains and West bringing the return of above to well above normal temperatures into the middle of next 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 (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 $$