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   FOUS11 KWBC 262025   
   QPFHSD   
      
   Probabilistic Heavy Snow and Icing Discussion   
   NWS Weather Prediction Center College Park MD   
   325 PM EST Wed Nov 26 2025   
      
   Valid 12Z Wed Nov 26 2025 - 12Z Sat Nov 29 2025   
      
      
   ...Significant winter storm with localized blizzard conditions will=20=20   
   continue to impact parts of the Upper Midwest/Great Lakes through=20   
   Wednesday as lake effect snow intensifies into Thanksgiving and=20   
   Friday for the eastern Great Lakes...   
      
   ...Confidence increasing on a second winter storm to affect the   
   Northern Plains Friday and the Midwest/Great Lakes Friday night=20   
   into Sunday...   
      
      
   ...Key Messages for both systems are in effect and linked below...   
      
      
   ...Great Lakes...=20   
   Days 1-2...   
      
   Strong surface cyclone, 991mb over the central U.P. of Michigan   
   this afternoon has a well- defined axis of deformation situated=20   
   over western portions of Lake Superior down through Wisconsin.=20   
   Peak cyclone intensity is now with a gradual occlusion phase   
   expected as it shifts east tonight. Powerful north to northwest=20   
   flow will continue to spread in behind the system making for   
   prolific lake effect snow (LES). This remains downwind of Lake=20   
   Superior through the overnight period with heavy snowfall=20   
   situated across all of the Michigan U.P. and the heaviest focused=20   
   across the the area from Ironwood over to Marquette. Lake effect=20   
   snows will increase over western lower Michigan through this   
   evening as WSWly flow veers to WNWly and increasing cold air   
   advection. General persistence in the flow coupled with multiple=20   
   shortwave perturbations moving around the periphery of the ULL=20   
   positioned over the U.P. and adjacent Ontario will maintain to a=20   
   multi- band structure downwind of Lake Michigan. Strongest bands=20   
   will likely reside off northern Lake Michigan down through Traverse   
   City with hi-res CAMs and Canadian Regional highlighting heavy   
   narrow banding (nearly single banding) from Lake Superior and   
   northern Lake Michigan fetch to the area northwest of Gaylord   
   through Thursday night. LES threat diminishes Friday as the flow   
   decreases with the low approaches the Gulf of St. Lawrence.=20   
      
   Downstream of the eastern Lakes of Erie and Ontario, persistent=20   
   LES pattern will ensue this evening behind the swift moving cold=20   
   front with snow formation across both lakes by midnight.=20   
   Prevailing southwest flow off Lake Erie will kick off the banding=20   
   along the southern periphery of the Lake up through the eastern=20   
   regions before manifesting into a more consolidated band structure=20   
   as it drifts south overnight. Winds will veer more out of the west=20   
   and northwest by Thursday afternoon with the banding positioning=20   
   becoming more pronounced off the southern periphery of Erie leading   
   to several inches of snow falling in the adjacent terrain downwind   
   of the Lake. Lake Ontario will see a similar pattern with=20   
   southwesterly flow veering back west in a similar time scale. This=20   
   will lead to areas of the Tug Hill and places downwind of the Lake=20   
   off I-81 seeing the initial heavy LES signature, eventually with=20   
   the banding shifting towards the southeast side of Lake Ontario.=20   
   Initial indications are for a long- fetch connection between Huron=20   
   and Ontario could enhance banding downwind of the lake on Friday=20   
   leading to several inches of snowfall across the southern portions=20   
   of the Tug Hill and points south and west.=20   
      
   WPC probabilities for an additional 8 inches of snow after 00Z=20   
   Thursday are at least 50% over much of the U.P. of Michigan (except=20   
   for areas closer to Lake Michigan), northwest Lower Michigan, far-=20   
   northeastern Ohio, northwestern PA, southwestern NY, and around the=20   
   Tug Hill Plateau. Within these regions, there is a smaller but still=20   
   significant area of probabilities between 40-70% for 18 inches of=20   
   snow. Isolated totals could exceed 30 inches, including what has=20   
   already fallen across the Michigan U.P. Best chances are likely over=20   
   the western U.P. terrain, areas downwind of Lake Michigan and=20   
   Traverse Bay, I-90 corridor along the southern lake shores of Erie,=20   
   and the Tug Hill down through Oswego county in western New York=20   
   state.   
      
   Travel will be difficult and perhaps impossible at times due to snow-   
   covered roads, blowing snow, and low visibility.   
      
   Kleebauer/Jackson   
      
      
   ...Northwest to Montana...=20   
   Days 1-2...   
      
   Developed low arrives to the WA Coast early Thursday with elevated   
   snow levels dropping to around 5000ft in the Cascades through the=20   
   day Thursday. Day 1.5 snow probs for >8" are 30-60% for the higher   
   WA Cascades.=20   
      
   An approaching shortwave trough descends Alberta Thursday night=20   
   and meets this low over ID/western MT on Friday. This combined=20   
   trough expands over the northern Rockies on Friday, promoting=20   
   downstream lee-side cyclogenesis near the eastern WY/CO border=20   
   Friday morning. 1040mb+ surface high pressure following from Canada   
   will help support some lower- level upslope-enhanced snow over=20   
   western MT where snow could be heavy at times over the Lewis Range=20   
   around Glacier NP particularly Thursday night. Day 2 WPC=20   
   probabilities for >8" snow are 50 to 80% over the northwestern MT=20   
   ranges down to the Bitterroots.   
      
   The arrival of Arctic air Thursday night allows snow for the   
   valleys/Plains of northern MT through Friday. Banding intensifies=20   
   north of the developing surface low with sfc-850 troughing and WAA   
   enhancing rates across northern MT through Friday morning with   
   lighter snows for the rest of the state into Friday evening. Day 2   
   snow probs for >6" are 20-50% over north-central MT.=20   
      
      
   ...Northern Plains through the Midwest...   
   Days 2/3...   
      
   A low level frontogenetical band will set up along the baroclinic   
   zone northeast of the developing low Friday. Expect moderate to   
   locally heavy snow to establish in an ever expanding swath of snow   
   across southwest ND and much of SD Friday, reaching central Iowa by   
   Friday evening. 3-6" snowfall can be generally expected through   
   this band with locally higher amounts possible given slow motion   
   away from its orientation allowing some prolonged snowfall.   
      
   By early Saturday, the upper trough will push onto the High Plains,   
   the surface low is well developed over southern KS with an inverted   
   trough extending northeast to Wisconsin. Broad cyclonic flow around   
   this trough with Gulf- sourced moisture allows for rapid expansion   
   to the precip shield Friday night/Saturday with ample cold air for   
   snow both on the WAA ahead of the low/ and through the entire back   
   side/comma head. Broad coverage of moderate to heavy snow develops   
   Friday night over eastern SD/southern MN/northern IA with expansion   
   east to lower Michigan then through Saturday. A strong pressure   
   gradient will make for blustery conditions. Probabilities for   
   notable snow continue to increase with current Day 3 WPC snow probs   
   for >8" 40-75% over southern MN down through central Iowa with a   
   contour of 40% >6" snow from far eastern SD clipping northeast Neb   
   and including much of northern IL, southwestern WI, and up to the   
   Twin Cities in MN.   
      
      
      
   The probability of significant ice across the CONUS is less than=20   
   10 percent.   
      
   Jackson   
      
      
   ...Winter Storm Key Messages are linked below...   
      
   Lake Effect Snow:   
      
   https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late=   
   stKeyMessage_1.png__;!!DZ3fjg!-l_s6iqeeDLG8U0cpRm4Ugv_XIj_L2CQQzY8a-JrBs0c_=   
   c23jxXUqD4At1cseASflzM56Gg8cSClQJW3ckc29S1aTEE$=20   
      
   Northern Plains through Midwest System Friday-Sunday:   
      
   https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late=   
   stKeyMessage_2.png__;!!DZ3fjg!-l_s6iqeeDLG8U0cpRm4Ugv_XIj_L2CQQzY8a-JrBs0c_=   
   c23jxXUqD4At1cseASflzM56Gg8cSClQJW3ckc2aqw0z4A$=20   
      
      
      
   $$   
      
   =3D =3D =3D   
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