Albany, NY (Friday, January 13, 2006) - The next week will feature a lot of hair pulling from meteorologists along both coasts as an active pattern continues but with slightly higher wave amplification leading to stronger events spaced out every three to four days instead of every two to three days. Moist maritime air continues to flood North America with one quick shot of arctic air hitting the east coast in response to a strong low pressure that’ll move into the Canadian Maritimes on Sunday. Besides that, we are left with a rather stubborn polar Pacific airmass which will bring consistent higher elevation snowfall to western U.S. mountain ranges and mixed precipitation or rain changing to snow events in the northeast.

I’ll discuss each event in the regional forecast section as always, but this weekend will feature rapidly changing weather conditions in the northeast as another storm system moves into the western region and will affect a large spatial area from the northwest to southern Colorado. This system will then move east and lead to another ugly system over New England. We have a strongly positive NAO and a neutral PNA which seems to be heading negative which bodes well for western skiers while eastern skiers just deal with another one of those two week periods of garbage. The catch is that right now the subtropical jet will be the furthest south of anytime during the year due to the time of year. This will allow storm systems to move further south than they would early or later in the season so southern California should start to see more action and even a warm pattern in the east can lead to significant snowfall. Over the next month, unless I start to see some sort of major pattern shift and a large scale movement of arctic air from Siberia into Canada (cross polar flow) then I do not foresee any major change from the current polar jet/maritime air regime. Again, this is a good thing for most western resorts and a hit or miss situation for east coast ski resorts.

Regional Forecasts
Western U.S.
Friday will feature heavy mountain snow in the northern tier of the western United States from the northern Rockies to the northern Cascades. Also, the B.C. Coast Range and interior B.C. regions should widespread 6-12” with some areas seeing up to 18” such as Whistler-Blackcomb, Mount Baker, and Fernie. Throughout Friday night and on Saturday snowfall will spread southeastward and intensify as a cold front moves SE through a large portion of the west reaching Wyoming and Utah by Saturday night. Expect 6-12” of snowfall in mountainous regions stretching from SE B.C. through Idaho and down the Sierra. Best chance of 12-24” snowfall during Saturday will be at areas along the Sierra Crest above 8,000ft from Mammoth to Kirkwood. By Sunday, the cold front is sweeping through Colorado but the upper level energy looks to open up and split in response to the low in the northeast moving into the Canadian Maritimes which will open up the wavelengths over the Midwest. The storm system should lose some of its punch but some 6-12” snowfall amounts should fall two distinct regions in response to this split in the storm’s energy. One region will be in southwest MT and the Tetons and another will in the southern Wasatch, southern Colorado, and even down into the higher terrain of NE AZ and NM. In between that region, only light snowfall accumulations of 6” or less are expected on Sunday and Monday.

Total snowfall from this storm system through Monday morning looks to be 12-24” up and down most of the west coast regions from Whistler-Blackcomb all the way to Mammoth. Inland, the heaviest snow splits with one maximum in the Bitterroots/Tetons/Sawtooth Ranges and another in the southern Rockies. These areas should also see a solid 12-18” with 6-12” in the northern Wasatch and central Rockies.

Following that, the next system enters the Pacific Northwest on Tuesday morning and it should drop similar or greater snowfall amounts than its predecessor. Timing between storms should be around one every 72hrs which then last for 18-24hrs.

Eastern U.S.
A very complex weather system will impact the eastern United States during the weekend beginning late Friday night and lasting into Sunday. The models were converging on a solution earlier in the day on the 12z Thursday models but the 00z Friday model solutions have split again. One camp develops a stronger low pressure system with some rare +NAO phasing bringing a heavy rain to snow/wind scenario into New England. The other camp does not phase the systems and brings the entire low pressure system much further south and out to sea with nothing of much significance, besides some rain to light snow with little wind, into the northeast. I am personally more inclined to believe the stronger, more phased solution will prevail due to model continuity, western U.S. amplification causing a more northward track in the east, and gut intuition. One of the things with watching the weather all time leads me to try to envision in my head, how a certain storm will play out.

I’m looking for the upper level low to cut-off and track from the lower Ohio River Valley through the mid-Atlantic and then going negative south of New England and eventually swinging through the Gulf of Maine. Strong upper level jet and right rear quad moving through New England will support a heavy precipitation event with total liquid equivalent amounts on the order of one to two inches. The surface low pressure track should follow the 500mb upper level low track fairly well and the system becomes vertically stacked from the surface through 750mb and 500mb over eastern New England on Saturday night. This supports rain changing to snow with deep cold air being advected into the backside of the storm. Most areas from upstate NY through New England will see a quick flash freeze on Saturday night with 1-4” of pasty, windblown snow. The higher elevations of the northern Adirondacks, Green Mountain spine, and White Mountains will see more significant 4-8”snowfall, with isolated 12” amounts, on the higher northwest facing slopes. Good moisture transport around a strong low by the time it reaches the Gulf of Maine coupled with orographics and cold air advection should produce a rather tight band of heavy snow somewhere in VT, NH, or ME. The idea being that with cold, dry air coming in from the northwest and moisture overriding it from the NE will produce a thin band of strong frontogenic forcing running north-south and moving slowly to the east before dying out as upper air dynamics move northeastward into the Canadian Maritimes. Someone should see a windblown 8-12” snowfall out of this and it will likely be the usual suspects such as Jay Peak/Stowe/Smugglers Notch region through Wildcat and towards Sugarloaf. The Adirondacks are a tough call as I think the heavy snow band will miss them to the east but still 2” (south) to 5” (north) should accumulate. Further south of I-89 in Vermont and into the Berkshires, look for 3-7” on Saturday night and into Sunday morning. Little if any snowfall should occur south of I-90. High winds will also be a problem on Sunday and some lift problems are likely, especially in the morning.

Remember, all of this is after up to 1” of liquid rain and temperatures in the 40-50F range so I do expect a net loss in snowpack. It in no way looks like a positive situation but at least some backside snow should allow for surface conditions to recover more quickly.

Following a 24-48hr cold shot, another strong warm air advection pattern should develop by midweek with some light overrunning snow changing to freezing rain in sheltered valleys as temperatures warm aloft. Another rain to snow event on Wednesday and Thursday looks to be in the offing. It certainly is not a favorable pattern for endless powder days in New England. Stick with it because February and March could be rocking.