BBS: TELESC.NET.BR Assunto: HVYSNOW: Probabilistic Heavy Snow And Icing Discussion De: COD Weather Processor Data: Sat, 14 Mar 2026 19:48:12 +0000 ----------------------------------------------------------- FOUS11 KWBC 141948 QPFHSD Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 348 PM EDT Sat Mar 14 2026 Valid 00Z Sun Mar 15 2026 - 00Z Wed Mar 18 2026 ...Northern High Plains through the Great Lakes...=20 Days 1-3... ...Blizzard expected this weekend with widespread major impacts=20 and record-breaking snowfall for portions of the Upper Midwest and=20 Great Lakes... Confidence continues to be high for a widespread major winter=20 storm from the Northern Plains through the Upper Midwest and Great=20 Lakes as a lee surface low lifts northeast and rapidly deepens into an increasingly moist column. While it is this lee cyclone that=20 will be responsible for the most significant impacts, this event is really two-pronged with the first event already ongoing across the Northern High Plains. The more significant portion of this event has begun this=20 afternoon as lee cyclogenesis begins in more impressive fashion=20 east of CO/WY. A digging shortwave over Idaho, Montana, and=20 Wyoming will drive impressive height falls downstream, with=20 impressive jet streak intensification occurring as a result. The=20 overlap of height falls with this jet development will lead to a=20 rapidly deepening surface low tracking from CO to IA before 12Z=20 Sunday.=20 After 00Z Sunday is when this event truly becomes a major winter event with widespread considerable impacts. As the surface low continues east from the Central Plains it will encounter dual=20 moisture streams, one from the decaying AR pushing east, and a=20 second as the theta-e ridge begins to arc northward on intensifying WAA/southerly flow out of the Gulf. The overlap of robust deep=20 layer ascent with maximizing moisture return will deepen the low=20 substantially, and help expand a considerable precipitation shield, with heavy snow arcing from SD through the Great Lakes by Sunday morning, and then slowly pivoting northeast while continuing=20 through D3 as the surface low moves into Ontario by 00Z/Tuesday. The synoptic setup is extremely favorable for a classic Midwest winter storm with widespread intense snowfall. Embedded bands=20 with snowfall rates of 1-3"/hr are expected as reflected by high=20 potential for CSI and even CI in model cross-sections Sunday aftn=20 into Monday which drives intense omega into the TROWAL. Although=20 guidance has continued to trend north, there is high confidence in a laterally translating band of heavy snow from SD into MN Sunday=20 morning, with the environment transiting into one that matches the=20 conceptual model for a pivoting band over eastern MN and WI Sunday=20 evening into Monday, It is in this area where the heaviest snowfall is expected, and potentially record, or near-record 2-day snowfall is possible from eastern MN through WI and northern MI. Elsewhere, snowfall rates of 1"/hr or more are still likely at times, just=20 with lesser duration. These snowfall rates combined with gusty=20 winds reaching up to 60 mph will create blizzard and near-blizzard conditions and whiteouts, with major to extreme impacts progged by the recent WSSI-P. Even in areas that get lower snow totals, the=20 blowing snow potential will still result in difficult travel, and=20 it is likely that most forms of transportation will be treacherous=20 at best, and impossible at worst, through the event across a large=20 area from Montana to Michigan, and everywhere in between. Event-total snowfall is likely to be extreme in some areas. This is reflected by 72-hr WPC probabilities (ending 12Z Tuesday) that are high (>70%) for at least 12" from the Coteau des Prairies of SD eastward through the Twin Cities, across much of north-central WI, and the entirety of the U.P. of MI. Where snowfall is most prolific, likely in northern WI and the U.P of MI, WPC probabilities indicate a 70-90+% chance of at least 24", and localized totals of 3-4 feet are possible before this event ends.=20 This could result in record snowfall in some places, and with SLRs being slightly below climo, combined with the strong winds, power=20 outages and long-lasting impacts are expected. For these reasons,=20 Winter storm key messages are in effect, and are linked below (Key=20 Message 1). After 00Z Tuesday, snowfall rates will be waning rapidly in direct association with the storm, transitioning more and more to lake- effect snows downwind of all of the lakes. Pronounced CAA on NW=20 flow in its wake could result in some lake effect snow in the=20 favored NW snow belts downstream of all the Great Lakes. WPC=20 probabilities are moderate (50%) for at least 4" of snow from LES=20 in SW MI, as well as along the Chautauqua Ridge and into the Tug=20 Hill Plateau. Additional heavy snow will occur near Marquette, MI=20 as well, adding onto the extreme snowfall event there the next few=20 days. The lake- effect will continue into Tuesday morning before=20 largely dissipating. On the S/SE side of this snowfall swath, an axis of mixed=20 precipitation is likely, leading to icing accretion from central IA through southeast WI and into lower MI. The most significant icing is expected for lower MI where WPC probabilities for at least=20 0.25" of ice have climbed to near 60%, and the axis of higher=20 probabilities for at least 0.10" of ice have extended back into SE=20 MN. Wegman/Weiss ...Winter Storm Key Messages are in effect. Please see current=20 Key Messages below... https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!7bG1910CLlgLJuzDPd_Vczrgw-IRTElc1yUV_8uBMMFVE= vbn7GQcCSQee7usdL_U3DMmDf_kaBI_viSxwjX0jWTvFfk$=20 $$ =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.28-Linux * Origin: Capitol City Online (1:2320/107) ----------------------------------------------------------- [Voltar]