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   FOUS11 KWBC 160801   
   QPFHSD   
      
   Probabilistic Heavy Snow and Icing Discussion   
   NWS Weather Prediction Center College Park MD   
   301 AM EST Mon Feb 16 2026   
      
   Valid 12Z Mon Feb 16 2026 - 12Z Thu Feb 19 2026   
      
      
   ...Pacific Northwest...   
   Days 1-3...   
      
   A strengthening 500mb trough will dig south down the British   
   Columbia coast towards Washington State. The trough will quickly   
   close off into a closed low west of British Columbia Monday night   
   into Tuesday with 500mb heights below the 0.5 climatological   
   percentile. The low will drift east over the Columbia River Valley   
   Tuesday evening and open up into a trough early Wednesday morning.   
   Then as that low exits to the east, one more shortwave trough over   
   coastal British Columbia heads for the Olympic Peninsula Wednesday   
   night. With this very complex, rapidly changing, but slow-moving   
   upper level pattern evolution, a prolonged period of active weather   
   is expected over the Pacific Northwest.   
      
   Sharp height falls and excellent 500mb PVA, combined with an   
   influx of 850-300mb mean-layer moisture and upslope enhancement,   
   will produce periods of snow over the Olympics and WA/OR Cascades   
   through mid-week. Snow levels will plummet to as low as 500ft   
   around the WA Cascades and Olympics Monday night and into Tuesday   
   morning, while 2,000ft snow levels in the OR Cascades will be more   
   common. Some of OR's coastal range could see snow down to   
   elevations as low as 1,000ft on Tuesday, and even some very light   
   snow possible along I-5 from the Tacoma/Olympia area on south   
   through the Willamette Valley. The heaviest snowfall is expected   
   above 2,000ft where 72-hour WPC probabilities are now into the   
   higher moderate range (50-70%) for additional snowfall totals >8"   
   for snowfall in the lower WA Cascades and most of the OR Cascades.   
   WPC probabilities for snowfall >4" remain in the moderate range   
   (40-60%) for Snoqualmie and Stevens passes. Given the long duration   
   but lack of heavy hourly rates, WSSI-P shows the chances for Minor   
   Impacts are generally on the low side (20-40%). The only exception   
   is the OR Cascades where there are moderate chances (40-60%) for   
   Moderate Impacts (hazardous travel, some closures/delays possible)   
   above 1,000ft. Note that the WSSI-P does show low-to-moderate   
   chances (20-40%) for Minor Impacts along I-5 from Olympia on south   
   to Eugene Monday night and into Tuesday. Impacts are most likely to   
   be a combination of snow covered roads and reduced visibilities.   
      
      
   ...California...   
   Days 1-3...   
      
   ...Multiple days of heavy and disruptive snowfall to affect the   
   California mountain ranges this week...   
      
   A pair of potent Pacific storm systems are working together to   
   direct copious amounts of moisture at the mountain ranges of the   
   "Golden State". While heavy snow has been unfolding in the   
   Siskiyou, Shasta, Trinity, and Salmons mountains of northern CA   
   since Sunday, today marks the beginning of very heavy snowfall   
   along the Sierra Nevada with snow levels initially starting out   
   around 6,000ft, then falling to as low as 3,000ft by Monday night   
   in the northern Sierra, and 4,000 ft for the southern Sierra   
   Nevada. Snowfall rates between 1-2"/hr will be common with some   
   instances of >3"/hr snowfall rates in the central and southern   
   Sierra Nevada. Heavy snow is also expected in the Transverse Ranges   
   above 6,000ft.   
      
   On Tuesday, another round of heavy snow is expected across just   
   about all of the CA mountain ranges as a second, arguably stronger   
   upper level low dives south along the West Coast, closely following   
   the first. This will spike onshore flow and additional moisture   
   supply on the southern and eastern flanks of the upper low. Snow   
   levels will fall to around 1,000 ft in far northern California   
   (including the northern coastal range) Tuesday night, around   
   2,500ft in the Sierra Nevada, and just below 5,000 ft into the   
   Transverse Ranges. Snow will continue to fall across California's   
   mountain ranges trough Wednesday as yet another 500mb shortwave   
   trough west of WA continues to sustain what feels like an endless   
   supply of Pacific moisture into the Golden State. With the longwave   
   trough overhead, snow levels could creep down as low as 1,000ft in   
   central CA and may support minor accumulations down to 1,000ft.   
      
   California's mountain ranges welcome the snow, although it will   
   come down fast and furious through mid-week. Through the end of   
   this discussion's timeframe (12Z Thu), snowfall will be measured   
   in feet above 4,000ft along the Sierra Nevada. WPC probabilities   
   show high chances (>90%) for >30" of snow along Donner Pass   
   through 12Z Thursday and more snow still to come. The WSSI shows a   
   large swath of Extreme Impacts (Substantial disruptions to daily   
   life; extremely dangerous travel or impossible driving conditions,   
   extensive closures) for elevations generally above 5,000ft,   
   although some Major impacts as low as 4,000ft are possible. Major   
   to locally Extreme impacts are showing up in the peaks of the San   
   Gabriel and San Bernadino mountains, with mostly Moderate-to-Major   
   Impacts (increasingly more disruptive to travel jumping from   
   Moderate to Major). There are also likely to be some Major impacts   
   in the Coastal Range of northwest CA above 2,000ft. Note that   
   there are Minor to locally Moderate Impacts expected along I-5   
   around Mount Shasta, signifying potential travel delays for I-5 in   
   the more elevated terrain of northern CA.   
      
      
   ...Intermountain West...   
   Days 1-3...   
      
   Pacific moisture ahead of the longwave upper trough off the West   
   Coast will spill over the Cascades and Sierra Nevada and reach many   
   ranges across the Intermountain West this week that badly need the   
   boost in snowpack. With a lack of a frigid airmass ahead of this   
   healthy moisture source, the bulk of the heavy snow will be largely   
   confined to many of the taller mountain peaks that sorely need   
   beneficial snowpack. The heaviest snowfall on Monday will reside   
   in the Blue, Sawtooth, Wind River, Uinta, and as far south as Mt.   
   Charleston and the Mogollon Rim. WPC probabilities are high (>70%)   
   for snowfall totals >6" in these mountain ranges through Monday   
   night.   
      
   On Tuesday, the highly anomalous upper-low off the Pacific NW coast   
   will help to usher the initial upper low over southern CA east into   
   the Intermountain West, causing widespread height falls and a   
   larger plume of Pacific moisture to pass over the Rockies. The   
   potent closed low off the Pacific NW coast on Tuesday then heads   
   inland over the interior NW and northern Rockies on Wednesday,   
   prompting snow levels to crash and most valleys (except the   
   eastern WA Columbia River Basin) are likely to see at least a   
   coating of snow. Still, the lack of a frigid airmass at the surface   
   will keep the bulk of the heavy snow in the mountains with ranges   
   such as the Wasatch, Bear River, Tetons, Uinta, Wind River,   
   Mogollon Rim, and CO Rockies seeing anywhere from 1-2 feet of snow.   
   Expect Minor to Moderate Impacts, per the WSSI, with travel over   
   passes from the Lewis Range and Bitterroots to as far south as the   
   Mogollon Rim likely to contend with hazardous travel conditions.   
      
      
   ...Northern Plains & Upper Great Lakes...   
   Days 2-3...   
      
   A powerful cyclone forming in the northern High Plains on Tuesday   
   will be the focus for heavy snow and blowing snow from northern MT,   
   as well as periods of snow and accumulating ice in the Upper   
   Midwest and Great Lakes Tuesday night. The storm system itself will   
   feature MSLP values in low-mid 980s over the Dakotas with blustery   
   winds in just about all quadrants of the storm. Beneath the TROWAL   
   over northeast MT and ND, hourly snowfall rates up to 1"/hr are   
   possible Tuesday night into Wednesday morning with wind gusts   
   topping 40 mph in eastern MT and western ND. Meanwhile, strong WAA   
   aloft overrunning a sub-freezing airmass will not only foster heavy   
   snow in northeast ND and northern MN, but also allow for freezing   
   rain to unfold from north-central MN on east through northern WI   
   and into northern MI. The worst of the icing is likely to occur   
   Tuesday night and into Wednesday morning in these areas. The   
   heaviest snowfall is expect to unfold in the MN Arrowhead where   
   lake-enhanced snowfall will play a vital role in areas receiving   
   over a foot of snow.   
      
   WPC probabilities feature moderate chances (40-60%) for ice   
   accumulations over one-tenth of an inch over the tip of Michigan's   
   Mitten, as well as along the southern shores of the Upper   
   Peninsula. In terms of snowfall, WPC probabilities show moderate-   
   to-high chances (50-70%) for snowfall totals >4" from northeast MT   
   across northern ND, northern MN, and the northern shores of the   
   Upper Peninsula. The MN Arrowhead sports the highest odds of   
   receiving over a foot of snow with WPC probabilities showing   
   modertae-to-high values of 50-70%. There are even some low-to-   
   moderate chances (20-50%) for localized amounts surpassing 18" in   
   the Arrowhead through Wednesday. The WSSI shows a large swath of   
   Minor to Moderate Impacts in these areas between Tuesday and   
   Wednesday, showing an extensive part of the North Central U.S.   
   will be subjected to hazardous travel conditions starting Tuesday   
   and lasting through Wednesday.   
      
      
   ...Northeast...   
   Day 3...   
      
   The strong low-level WAA ahead of the powerful storm system in the   
   Upper Midwest will stretch as far east as the Northeast on   
   Wednesday. High pressure over southern Canada is providing enough   
   cold air to support wintry precipitation, although precipitation   
   type will largely depend upon the depth of the sub-freezing   
   temperatures within the boundary layer. Guidance is coming into   
   decent agreement on a narrow tongue of QPF >0.5" over much of   
   Upstate NY and as far east as the Berkshires and Green Mountains.   
   However, guidance disagrees on the placement of this band of heavy   
   QPF. The farther south the band is, the farther away from the   
   source of the colder air it becomes, making a combination of snow,   
   freezing rain, and event potential plain rain in lower elevation   
   areas. However, farther north solutions would place the band of QPF   
   over the Adirondacks and Green Mountains, which would favor   
   heavier mountain snow there. Then there is the conundrum of   
   precipitation rates. While rates may start off heavy via strong   
   850mb FGEN, as the storm weakens over the Upper Midwest on   
   Wednesday so does the influx of WAA, leading to frontolysis aloft   
   that would weaken low- level forcing and reduce the dynamic cooling   
   aloft to support periods of heavy snow.   
      
   This is all to say that there remains a fair amount of uncertainty   
   in the forecast. WPC probabilities are indicating the Adirondacks,   
   Green, and White Mountains have low-to-moderate chances (30-50%)   
   for snowfall totals >4" through Wednesday night. Given the   
   uncertainty in the position of the heaviest QPF and lingering   
   questions regarding low-level thermal profiles, areas   
   with elevations over 1,000ft would be most favored to see some   
   accumulating snowfall on Wednesday. The Champlain and Upper Hudson   
   Valleys would likely reside just far enough north to support   
   measurable snowfall, as evident in WPC's probabilistic guidance   
   that highlights moderate chances (40-60%) for snowfall totals >1"   
   on Wednesday. Lastly, some minor ice accumulations are possible as   
   far south as the Lower Hudson Valley and southern New England with   
   probabilities showing low-to-moderate chances (20-40%) for at least   
   one-hundreth of and inch of ice accretion on Wednesday.   
      
      
   Mullinax   
      
      
      
      
   $$   
      
   = = =   
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