Thursday, January 31, 2013

New snow is on the way, just a question of when and how much

Temperatures fell quickly Thursday back to sub-freezing levels after an incredibly damaging thaw featuring an "all of the above" plethora of snow eating variables including warmth, high dewpoints, wind and rain. We will need a lot of help to recover but help is coming in immediate fashion. Low level instability combined with Great Lakes moisture will work to induce the terrain enhanced snow showers that we are typically so dependent on. The period between between Thursday evening and midday Friday should feature on and off snow showers and squalls, enough to produce 3-5 inches of powder before it dries out Friday afternoon. This is much needed first aid but the mountain will obviously need a bit more before returning to top form.

There is plenty weather worthy of discussion over the next week or so and I am happy to report that none of this talk will concern rain. Temperatures will be on the colder side of average with most of these days below 20 on the mountain and a few nights below zero. A series of clipper disturbances rotating through the polar jet will impact New England and there are important questions relating to where and how much it will snow. The first will dive into the Midwest Saturday as a disjointed and disorganized system. There essentially is two weak upper air impulses with the second catching the first on Sunday, giving it a much needed boost as it interacts with the Atlantic Coast. The result could be either good or bad. If the system can strengthen quickly and efficiently it could effectively suck moisture back over interior New England. If the system is slow to strengthen as it encounters the coastline, it could act to simply consolidate its energy off shore as a couple of recent clippers have done this month. I am worried about the latter and some of the recent computer guidance is indicating such an outcome but even in this case, limited amounts of moisture should be enough to produce a light 1-3 inch snowfall Sunday, hopefully its more. One or perhaps even two additional clipper systems will track across the Midwest early next week. Models have shifted the track of this system or systems southward in the last 24 hours. That being said, the situation has been very fluid and small changes in timing or interactions make the outcomes look different every time new model data is released. 24-hours ago, there were stronger indications that one of these systems would blow up off the coast and become a significant snow producer and I would not declare that possibility dead yet.

The cold weather will persist in to the later stages of next week and then the arctic air will begin a retreat into central and northern Canada. Milder Pacific air will thus be allowed to dominate much of the country by the 10th or so of the month. In spite of all this, and the inevitable mention of the "evil empire", there is a silver lining in the forecast. The cold will not give ground quickly and a more significant weather system will likely move out of the Rocky Mountains late next week and is likely going to be one of the first more organized snow producers to have a more direct impact on the region in too long. So even as the more intense cold is retreating, the weekend of the 9th and 10th could be one of the better weekends since early January. Thereafter, the evil empire will become a more dominant player but maybe not too dominant. Ensembles indicate a strengthening of a ridge in the Pacific coupled with a trough over Alaska. This combination floods the country with Pacific air as mentioned and temperatures on the mountain will certainly warm by the 11th of the month. It is possible however that the evil empire has a short reign of terror this go round as the signal is expected to quickly weaken within a few days. It has been a noticeable characteristic of the winter season 2012-13. Warm or cold patterns have generally failed to gain a lasting foothold on the region and we have watched weather conditions swing violently in both directions since early December.


1 comment:

K2Kite said...

Thanks, Josh. If any of this gig gets too discouraging for words or you seek the next great ("off season") challenge, consider a backup plan formulating wind forecasts for the tricky micro-climate of Champlain for the kiting community. The NWS has ceded any serious attempts at modeling this stuff for us. If anything, they overestimate wind and waves to protect boaters, but just as often low-ball the potential for wind and we're caught napping. Meanwhile, hang in there.