From the Skiing Weatherman...I sure hope he is right!!
Tick, tick, tick...here comes winter...
Weather discussion 12/08/04
It's another nasty day as I put fingers to keyboard today...high 30's...drizzle, fog, and rain on the way...but I'm still smiling because I think I know what's coming in the next couple of weeks, and I think skiers and riders are going to like it. The pattern change that I have alluded to repeatedly during the past week is still ongoing, and winter is still about to descend on much of the country...more on that in a moment.
The biggest snow producer today is to be found in the west, as another Pacific system is currently dropping fresh snow on the Cascades and Sierra. Anywhere from 6 to 12 inches will fall in the Cascades, while the Sierra, particularly around Tahoe, are looking at 2 feet of new snow above 7,000 feet. There are several Pacific systems involved in the overall stormy pattern in the west right now, and they will all race ashore and through the Great Basin between now and Thursday or so. Snow will also fall in the northern Rockies, through the Tetons and Bitterroots, southward to the Wasatch, where 1-2 feet should fall on the Salt Lake City region resorts this week. Right now, it looks to me as though this series of storms in the west will be the last for a while, as an upper level ridge will start to build in that part of the country. As most weather watchers know, if there is a ridge in the west, correspondingly you are likely to find a trough in the east.... and that is just what is about to develop. When an upper level ridge is overhead, you can count on bluebird skies (with wood smoke and auto emissions trapped under an inversion in the valleys), but very little in the way of new snow.
The east is far behind schedule in terms of open terrain, but a dramatic game of catch-up will be starting in the next 5 days or so. The game actually got underway-late last week in far northern New England, where Jay Peak picked up about a foot and a half of snow in repeated clipper/snow shower episodes. This past weekend was quiet in the east, and when a shot of cold air came south from Canada Saturday night and Sunday, a 24-hour snowmaking window opened up in New York and New England. Yesterday, mild air overran the cold and produced snow from central Pennsylvania to New England, with 2 or 3 inches the most reported anywhere. Last night, the milder air continued northward, changing the snow over to rain, or a mixed icy mess...thankfully, amounts were light, so travel troubles were minimized. The primary surface low in this mess will pass west of New York and New England, so a shot of rain will fall this afternoon and tonight, and a 6 to 10 hour period of strong winds will rush in behind the departing low on Wednesday. Cold air will not follow the midweek system, so snowmaking will be sporadic between now and the weekend.
By late in the week, the western system will have moved southeastward to the central Appalachians, and a surface storm will be forming by Friday. It looks to me as though the first low will travel up the spine of the mountains, and a secondary low will crank up along the mid Atlantic coast. Initially, it will be too warm for snow in the east, so look for Friday rain, all the way into the mountains of northern New England. As the secondary low takes over, and as the upper level trough grows stronger, the environment throughout the circulation of the storm will be cooling, and an elevation-based changeover to snow will occur. This time, cold air will follow the storm, as the trough becomes established in the east, making the delivery of Canadian air much more direct. By Saturday, the coastal low will be dominant and snow showers will be occurring all the way south to the mountains of north Georgia. More importantly, resorts in the southern and central Appalachians will finally have the chance to make meaningful snow...many will be turning their systems on for the first time. Further north, the changeover to snow in western Pennsylvania and western New York will happen early enough to allow several inches of snow to accumulate. In eastern New York (the Catskills and Adirondacks), snow will also take over, with the Adirondacks looking at a plowable (and groomable) storm before it ends late Saturday. Northern New England areas are looking at 6 inches plus, in my opinion. Remember, the changeover will be elevation based, as the cold air deepens. This will be a situation where a large-vertical area will have a sizable difference in new snow from their summit to their base.
Late in the weekend, an Alberta Clipper will race through the east, with another round of snow the result...no rain, just snow. New York and New England look like the likely candidates for a few inches of fluff. Once that clipper goes through, winter will have arrived, because the first significant chunk of arctic air will arrive from Canada. Resorts in central and western New York, and to a lesser extent western Pennsylvania and West Virginia, that depend on lake effect snow for help with base building...well, they'll be very happy with next week's weather. Several shots of reinforcing cold air will be passing over the relatively warm waters of the Great Lakes, and that means the lake effect machine will be cranking. The upper level ridge in the west will hold strong, and that will help the cold air to target the east until further notice.
I mentioned last week that I felt the two weeks or so that lead up to Christmas looked to be cold and stormy in the east...I still feel that way. With a strong, deep trough in the east, combined with the ridge in the west, cold air will be plentiful. As for the stormy component...a deep upper low in the Gulf of Alaska will send impulses up and over the western ridge, and these will then head southeastward...as Alberta Clippers. Meanwhile, the weak El Nino will be sufficiently strong to send packages of energy eastward in the southern branch of the jet. The tendency will be for the impulses from the two branches to merge at or near the base of the eastern trough. When the timing is right, and they do merge, or "phase", the result is most often an east coast storm. It is nearly impossible to predict the dates of such events with a lead-time of much over a week, but when all the pieces are in place, it is not unreasonable to forecast a period of cold and snowy weather, and I think that is exactly what is in the cards when the trough gets established. The clock is ticking, and the trough will be ready to call the east home by the end of the upcoming weekend.
SO, the lions share of the winter weather has been in the west thus far this season, and that region will get another good shot of snow this week...then the worm is going to turn, and the eastern resorts will be engaged in a large scale game of catch-up. By the end of this weekend...GAME ON!!!!
