BBS: TELESC.NET.BR Assunto: HVYSNOW: Probabilistic Heavy Snow And Icing Discussion De: COD Weather Processor Data: Tue, 24 Mar 2026 07:12:05 +0000 ----------------------------------------------------------- FOUS11 KWBC 240711 QPFHSD Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 311 AM EDT Tue Mar 24 2026 Valid 12Z Tue Mar 24 2026 - 12Z Fri Mar 27 2026 ...Washington Cascades & Olympics... Days 1-2... A strong and meandering closed upper low in the Gulf of Alaska will direct a storm system forming on its southern flank at British Columbia the first half of the week. With the Gulf of Alaska low slow to move east and low level ridging in place off the southern CA coast, low- level SWrly flow will supply a narrow corridor of Pacific moisture into the Pacific Northwest today and into Wednesday. Snow levels will generally reside above 3,000ft today, but a cold frontal passage and falling 700-500mb heights Tuesday night will cause snow levels to dip to as low as 2,000ft by Wednesday. Still, the cold air in wake of the cold frontal passage is not particularly cold, and the best moisture advection will have already concluded by Wednesday. This is likely to cause periods of mountain snow on Wednesday in the Olympics and Cascades to as low as 2,000ft, but rates will not be overly heavy even through Wednesday night. WPC probabilities for >4" of snow are high (>70%) for elevations above 4,000ft north of I-90. Stevens Pass sports high chances (>70%) for snowfall totals >4" through Wednesday night, while Snoqualmie Pass has moderate chances (50-70%). Stevens Pass poses the slightly better odds for snowfall totals >8", ranging between 30-50%. Some locally hazardous travel conditions are possible at pass level, but the heavier totals surpassing 8" will likely be found at higher and more remote elevations. ...Northern Maine... Days 2-3... Starting Wednesday night, sheared lobes of 500mb vorticity racing over the northern Great Lakes will generate PVA over northern New England at the same time that low-level SWrly flow results in low- level WAA and increased moisture content. Weak high pressure over Quebec and sufficiently cold enough air over Maine will support periods of snow over northern Maine with some minor icing possible in central ME. As the first disturbance races east, a second 500mb shortwave trough will spawn a second low over the northern Mid- Atlantic Thursday evening. Periods of snow may envelope northern Maine Thursday night as a cold front races south and forces boundary layer temperatures to crash below freezing. There remains some model spread in solutions regarding this second round of snow Thursday night, so confidence in the snowfall placement and amounts for the second round of snow is lower. At the moment, 48-hour WPC probabilities show low chances (10-30%) for snowfall totals >4" along the ME/Quebec border. The chances for significant ice across the CONUS is less than 10 percent. Mullinax $$ = = = 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]