Monday, November 12, 2007

Warmth & Rain through WedBut Cold is not far behind

First, a quick summary of events:

Hurricane Noel blew through New England last weekend with wild winds and rain along the coast. The low moved north towards 50N/50W.

A dry cold front then crossed the region Wednesday of last week, resulting in the coldest temperatures so far this season through today, including a high of 39 (first below 40) on Saturday and a low of 19 (first below 20) this morning. For the past week, we have followed a crazy path drawn by the models with very inconsistent forecasts. This was for a storm system moving across the Great Lakes region into PA and a second low forming off the M/A coast. The storm ended up going well southeast of New England, but in fact gave parts of Maryland, New Jersey, Pennsylvania, New York, Connecticut, and Massachusetts their first snowfall, and in some case first accumulation.

With the intial cold front last week, the NAO and AO have dropped below zero SD, and in the case of the AO, it is approaching -2 SD. The ensembles, just like the operational models have been less than reliable for the past month now. However, it is best at this point to follow ensemble means rather than the operational.

Here is the latest situation:

Storm system currently spread out across Quebec and into the Ohio Valley will bring precipitation to the region by early tomorrow morning. Currently, it appears WAA ahead of the front will keep the temperature from falling much tonight, meaning the precipition will likely stay in the form of rain. Any stray showers ahead of the main area that would reach here in the next 2 hours may have sleet mixed in.

Warm front cross the region tomorrow morning and highs soar into the mid 50's tomorrow afternoon. Another warm day will be on tap Wednesday as the cold front approaches. This front will have a significant cold air mass behind it. After lows remaining near 40 Thursday morning, temperatures will stay steady through the day. 850mb temperatures will fall to near -8 by Friday which will keep highs around 40.

The next big question is a storm system progged for Friday Night through Sunday. The EURO has been consistent in bring a clipper south from Canada and redeveloping the low off the coast with a nor easter moving just SE of Cape Cod on Saturday. The EURO is a more amplified solution, especially compared to the GFS which is staying progressive for the past few runs. It is been very inconsistent however, and not close at all to the ensembles. At this point, especially considering where the NAO is, the EURO is looking like the more feasible solution, and is the model of choice for both the HPC and NWS. The point forecast for Keene has recently added chance POPs through the weekend. Behind the storm, another cold shot is in store, and we may be talking about high 30 low 15 next week. Needless to say, this period is a low confidence forecast right now.

I'll leave you with a GFS treat which has showed up a few times in the past 3 days - a snowstorm around Thanksgiving, around the time period that I discussed in my winter outlook, when a brief +NAO regime arrises. I emphasize however the poor state the model is in right now and not something to be relied upon through 72 hours let alone 240. Nevertheless, here is is for your viewing pleasure:



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