Tuesday, January 12, 2010

MLK storm potential fizzles and some rough sledding lies ahead

We had a 5-6 week period of ultra favorable teleconnection indices but our run looks to be coming to an end. I would call it a run of good fortune except that I would've hoped such a setup would have yielded a seasonal snowfall of well over 100 inches by now. Instead we have storm taking aim at the Atlantic Ocean and a pattern dominated by mild air and embedded within that pattern is at least one rain event before the 25th of the month.

We will see a gigantic thaw hit the middle third of the country over the next week but interior New England will stay within the range of seasonable. Temperatures will moderate substantially from current levels reaching the freezing mark by Thursday and likely exceeding it Friday. Passing disturbances will be benign in nature. Friday's weak clipper system may bring a few snow showers but in the end will only allow a re-enforcing shot of chill to encompass the region for the weekend. The weekend as a whole should be free of major precipitation.

Our MLK storm is lacking the right jet configuration for a major hit. Preferably, an upper ridge axis near 110 west (The Alberta, Saskatchewan border) west is what it takes for a coastal system to take the needed left turn up toward New England. In this case the ridge axis is between 90 and 95 west and thus it will be very difficult to avoid a deflection. The system is juicy and potent enough to challenge the prevailing mid-latitude jet but the current data is overwhelming in its suggestion that the steering currents will win out and guide this puppy out into the Atlantic Ocean before any mischief is created.

Seasonable temperatures will remain in place through MLK day plus a day or two but our arctic pipeline is closed for business thanks to a monstrous upper ridge which will extend from the Hudson Bay to lower Quebec next week. The ridge's strength is no doubt being fueled by a freight train of jet impulses that will fill the interior west with unsettled weather and ensure some epic powder for the southern and central Rockies beginning early next week and persisting well beyond next week. As mentioned in the last post, it is important this energy transgresses quickly through the Rockies and into the plains and southeast. Bottling this energy in the Rockies will allow mild air to flood the eastern half of the country and remain there for a lengthy period of time. I would expect at least one rain event from the upcoming pattern and 2 would not be surprising. The AO shows signes of drifting back into negative territory by around the 25th of the month and with it should be the return of colder weather. The El Nino also appears alive and well and should kick some more juicy systems into the plains during the last week of January and we will have to hope that enough cold air can return by then for what will be some much needed snow after the mild weather.

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