A Look Ahead to February 2010

On this awfully cold night I figured it was time to look ahead to the upcoming month. This is pretty technical so if you just want the Cliffs Notes version just skip to the bullet points at the end. First, let’s take a look back at the rest of meteorological winter 2009-2010 in Windsor Locks.

December 2009 – Temperature Departure…-0.5º
January 2010 – Temperature Departure…+2.7º

The coldest part of the winter so far was the December 17th-25th period. Notice the high amplitude MJO during that period was in phases 7, 8, and 1. Since Christmas, the MJO has swung into the “spiral of death” (low amplitude) after moving through phases 3-5 around New Years.

Why should we care? Now that the MJO has regained amplitude we have a substantial wave moving across the Pacific Ocean. This canlead to some clues about the global weather pattern. The GFS ensemble and operational GFS MJO forecasts move the strong wave into phase 8 and possible phase 1 over the next 2 weeks.

If we go back and look at other February dates with a strong MJO in phases 8 and 1 you can see the weather pattern that results (below). This can be a piece of the weather puzzle. In general, phase 8 results in colder than normal weather across the northeast. Below you can see the 500mb composite for MJO phase 8 in February. Notice the blue shading over the northeast which corresponds with below normal heights and likely colder than normal temperatures. The question is now… will we actually see the cold?

I’m not exactly sure at this point. With a strong MJO wave in this phase I do expect some cold in the northeast with a trough over the east coast. I don’t think temperatures will be able to plunge, however, given the strong Pacific flow (remember: El Nino is still here). The GFS and Euro ensembles in the 8-10 day time frame (2/6-2/8) show a very active Pacific jet which should transport mild air across some (or most) of the country . Here in New England I’m expecting somewhat below average temperatures with an enhanced threat for storminess during the first 10-15 days of February.

In addition, the Arctic Oscillation and the North Atlantic Oscillation show signs of tanking (big time). You can see the massive positive height anomalies over the North Pole on the Euro and GFS which should displace the polar vortex to the south. With an active subtropical jet and plenty of Arctic cold around, we have a decent shot at seeing 1 or possible 2 good snowstorms around here. The one caveat is, however, a polar vortex displaced too far south (like this weekend) could cause some suppression issues with southern stream lows.

Here’s the bottom line:

  • Below normal temperatures. Most of the month will see somewhat below normal temperatures and there is the potential for one shot of very cold air. I’m predicting a departure of -1.5ºF at Bradley Airport.
  • Potential for a stormy 1-2 week period. There’s a decent chance at 1 or maybe 2 significant winter storms.



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