Quantitative Precipitation Forecast
Issued by NWS
Issued by NWS
923 FOUS11 KWBC 052005 QPFHSD Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 305 PM EST Fri Dec 5 2025 Valid 00Z Sat Dec 06 2025 - 00Z Tue Dec 09 2025 ...Pacific Northwest, Northern & Central Rockies... Days 1-3... A highly active storm track with several significant atmospheric rivers into the Northwest will usher in copious amounts of Pacific moisture from the Pacific Northwest on east into the Northern and Central Rockies the next few days. A steady barrage of >90th climatological percentile PWATs will stream across the Pacific Northwest into the Great Basin and Rockies through Saturday, with another round of >90th percentile PWATs arriving in the Pacific Northwest Sunday into Monday. Synoptic-scale forcing for ascent will be aided by a persistent NW-SE oriented 250mb jet streak with its diffluent left exit region overhead. Snow levels over the Pacific Northwest will dip as low as 3,000ft while the Northern Rockies generally hover around 4,000ft. As height falls occur over the Northwest through Saturday, snow levels will drop to as low as 2,000ft. That being said, the heaviest snowfall will be confined to elevations above 5,000ft in the Bitterroots, Lewis Range, and Sawtooth, above 6,000ft in the Tetons, Absaroka, Big Horns, Bear River, and Wasatch Ranges, and above 7,000ft in the central WY/CO Rockies. Snow looks to taper off across the Central Rockies by Saturday evening, but the next atmospheric river will deliver another plume of Pacific moisture and another round of heavy mountain snowfall across the Pacific Northwest and northern Rockies Sunday into Monday. WPC probabilities continue to be impressive on Day 1 across the higher terrain from Glacier NP through Yellowstone NP including portions of the Sawtooth/Salmon River ranges, Absarokas, terrain of NW WY, northern Utah, and into the Park Range of CO. Here, WPC probabilities reach above 70% for 8+ inches, with locally higher amounts of 1-2 feet generally above 6000 ft. Over the next few days, WPC probabilities paint a wintry picture across many of the Northern and Central Rockies, as well as the higher elevations of the Cascades (above 5,000ft) with high chances (>70%) for additional snowfall totals >18" in all of these listed ranges and elevations through Sunday. In fact, the higher elevations of the Lewis Range, Bitterroots, and Tetons have moderate-to-high chances (50-80%) for snowfall totals >24". Moderate to heavy snow continues later into Days 2 and 3 over the WA Cascades and northern Rockies, though probabilities suggest less snowfall compared to the more snowy stretches tonight into Saturday. The WSSI shows many areas of Minor and Moderate Impacts across the Northern and Central Rockies, including some locally Major Impacts. The Major Impact potential areas (considerable disruptions; dangerous travel and widespread closures) include areas along the Wasatch east of Salt Lake City and the more remote areas of these Intermountain West ranges. Residents in these mountain ranges should prepare for a multi-day stretch of winter weather that results in difficult and treacherous travel conditions. ...Northern Plains & Midwest... Days 1-2... A fast-moving clipper system, aided by a slug of Pacific moisture combined with strengthening low-level frontogenesis and warm advection, will support a swath of moderate to heavy snow from the northern Plains into the Midwest the next couple of days. The band of snow first starts to develop across the Dakotas late tonight into Saturday morning, then heads for southern MN and northern/central IA as it intensifies late Saturday afternoon and evening. The band then begins to weaken by early Sunday morning as the snow reaches the Lower Great Lakes and OH Valley. The latest WPC probabilities have increased with this forecast, now supporting probabilities of 50-90% for snowfall totals >4" for locations that banding (mentioned above) is most likely across the Midwest. However, given the favorable synoptic and mesoscale processes at play, a swath of heavier and more impactful snow still remains on the table, as evident in the low-to-moderate chances (30-50%) for snowfall totals >6" over northern/central IA. By Sunday, low probabilities (10-40%) of >4" of snow extend into southern Wisconsin and northern Illinois as the quick-moving wave weakens on its track into the Lower Great Lakes and OH Valley. Those in the Midwest should continue to monitor the forecast closely as additional changes in the placement and totals of the heaviest snowfall could still change over the next 24 hours. ...Great Lakes & Northeast... Days 1-3... Periodic mid/upper level impulses rotating within a broad cyclonic flow pattern will continue to support rounds of light-to-moderate lake effect snowfall across the upper Great Lakes through Monday. A cold frontal passage Saturday into early Sunday morning revitalizes LES bands over the Michigan U.P. and downwind of Lake Ontario over the Tug Hill. Then, the fast-moving clipper from the Midwest races across the Great Lakes and Northeast later Sunday into Monday, bringing more lake effect snow and likely a period of steadier synoptic snow to interior portions of the Northeast and northern New England. The latest 12Z guidance continues to suggest a fairly flat mid/upper level shortwave as it passes over the region, which would limit snowfall potential. That said, it would not be surprising to see models trend a bit more amplified and more snowy in future model cycles, so continue to monitor the forecast in the coming days. WPC probabilities show overall low chances (10-40%) of >4" of snow across portions of northern Michigan downwind of Lake Superior and Lake Michigan Saturday into Sunday. Low chances (10-30%) of >4" of snow then extend downwind of Lake Erie and Lake Ontario and across parts of northern New England Sunday into Monday. Miller/Mullinax $$