BBS: TELESC.NET.BR Assunto: HVYSNOW: Probabilistic Heavy Snow And Icing Discussion De: COD Weather Processor Data: Mon, 23 Mar 2026 18:44:33 +0000 ----------------------------------------------------------- FOUS11 KWBC 231844 QPFHSD Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 244 PM EDT Mon Mar 23 2026 Valid 00Z Tue Mar 24 2026 - 00Z Fri Mar 27 2026 ...Northern New England... Day 1... Latest surface analysis and RAP surface forecast indicate a defined inverted trough axis bisecting NH up into neighboring Quebec with some weak precipitation beginning to develop over far northern NH. Expectation is for ascent to maximize within the trough axis later this evening as flow focuses out of the north creating upslope flow orthogonal to the terrain of the White Mountains leading to a period of snowfall to develop as environmental conditions favor frozen hydrometeors. Despite modest PWATs present over Northern New England, the primary ascent pattern within the trough axis coupled with upslope flow will generate localized moderate snowfall for several hours creating a focal point of accumulating snow within the White Mountains and some of the neighboring valleys. WPC probabilities depict moderate- to- high chances (50-80%) for additional snowfall accumulations >4" in the White Mountains, which included Mount Washington. Otherwise, any additional snowfall accumulations below 2,000ft are likely to range between a coating-3". ...Washington Cascades & Olympics... Days 1-3... Little has changed from the previous forecast as the synoptic scale pattern remains persistent within all guidance across the Pacific Northwest. 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 later tonight carrying through both Tuesday and Wednesday. Snow levels will generally reside above 3,000ft through Tuesday, 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 moderate-to-high (50-80%) for elevations above 4,000ft north of I-90. Stevens Pass sports moderate-to-high chances (50-90%) for snowfall totals >4" through Wednesday night, while Snoqualmie Pass has moderate chances (40-60%). Both passes sport low-to-moderate chances (20-50%) for snowfall totals >8", so some locally hazardous travel conditions are possible at pass level, but the heavier totals surpassing 8" will likely be found at higher elevations for this event. The chances for significant ice across the CONUS is less than 10 percent. Mullinax/Kleebauer $$ = = = 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]