Wednesday, February 21, 2007

A real chance to save next week

Combustion has gotten the best of the first part of this week's forecast. In addition I promised an update on next week on Monday and failed to get to that. Obviously it is time to make amends with an update for the balance of the week into the weekend and an update on next week and March. I apologize for the delay (and the bust) but the good news and part of the reason for the delay was the recent purchase of a MacBook which will allow for more easier updates while traveling and in most cases skiing at MRG. More good news involves the forecast for next week which appeared threatening a few days ago, but the NAO is fighting very hard on our behalf and is turning what looked to be an ice to rain event to a very close call early next week with new snow now making up a good part of the possibility range.

An update to the busted forecast for this week
12-28 inches was the prognostication on Monday for the period Tuesday through Friday. It is clear that the prospects for the aforementioned appears in serious peril but new snowfall on Thursday and Thursday night will make up some of the ground. The culprit is a dynamically impressive clipper system which will vigorously carve a trough for the weekend in addition to the new snow. The storm will also bring new snow to Boston and the Cape, two areas which have seen amazingly little snowfall (less than 10 inches as of now for the year). As far as MRG is concerned we are on the northern edge of this rapidly digging system and although the dynamics appear impressive, moisture will be somewhat limited until this storm makes it to the coast. Snow will begin late in the day Thursday and continue through much of the night. It will be enough to re-freshen conditions but will amount to 5 inches or less (2-5 lets say) by first tracks time Friday. Models are hinting at some additional terrain enhanced snow late Friday into early Saturday but the unstable layer appears very shallow during this period based on forecast soundings making the prospects for significant snowfall in this time frame very low. If we do get some light snow Friday night and early Saturday, my guess is that it amounts to less than 2 inches but we will see. The rest of the weekend meanwhile will be dry. Sunshine should make an appearance at least late in the day Saturday although it will be chilly and blustery with high temperatures in the teens. Clouds will overspread the region again Sunday although it will not be as cold with temperatures climbing well into the 20's.

And finally for early next week...
A few days ago, ensemble data was indicating trouble, trouble and trouble for early next week. I reflected this concern in the last post on Monday although failed to expand on this as promised (again I apologize). The models themselves have been a lot more willy nilly and have generally failed at giving us any conclusive solution for early next week until today although there were plenty of runs showing ice and rain before a return to colder weather. In spite of the western trough which has materialized as expected, the forcing of the AO and NAO, both of which are negative, are making it extremely difficult for systems in the Rockies to take the nauseating St Lawrence Valley route to the maritimes. Instead, the systems try to cut north then re-form off the Atlantic coast thus choking off attempts to get warm air into the region. In the end what looked like trouble turns into more new snow which is amazing. We are not totally out of the woods here since the threat of mid-level warming still exists which would thus change any snow to sleet or ice for a time. The just released European however hammers home the point that much of the precipitation early next week is indeed snow which according to this solution would fall intermittently between Sunday night and early Wednesday. The system impacting the region has some moisture but is fairly disorganized (at least initially) so snowfall amounts are very hard to predict at this point. The moral of the story though is a positive one overall since we have a real good shot of escaping an ice or rain event early next week and instead getting at least a fresh few inches of new snow. Stay tuned for the final call on this one which should come no later than a few days hence.

And now to early March
Ensembles seem confident in the idea that the first few days in March sees a temporary weakening of the trough in the west while at the same time a not so insignificant trough amplifies across the eastern States. This is certainly some good news for late next week and into the first full weekend in March but the indicators are increasingly bearish going forward with all of the major teleconnection indicators moving to neutral or unfavorable by next weekend. The AO (Arctic Oscillation) is the most significant since its recent negative index has been a positive force on our weather and is expected to switch in sign in the next 7-10 days. In addition to that is the trough which is expected to remain in place across western Canada which will conspire with the then positive AO and become a strong force for zonal flow across much of the country around the time of March 4th. This could very well mean a thaw by the first full weekend in March over a huge span of the nation. The silver lining is that the Ensembles, though they show a warm signal for a good part of the nation in this time frame, are not especially warm in New England where normal is the indication based strictly on the interpretation of jet stream anomalies. We will see how it evolves over time but I am certainly less than thrilled with how the first full week in March (4th-11th) appears. With that said extending this period of great ski weather to the first full weekend in March is certainly a bonus and the active weather pattern should continue until then which will mean the chance for another storm during or just prior to the weekend of the (3rd and 4th).

The Quick Summary
In spite of the lack of new snow over the last few days, some is expected late Thursday. Good news for early next week with a real possibility of escaping a possible ice storm and instead receiving new snow.

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