Elliot Abrams

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Disquieting Signal From the High Stratosphere

March 20, 2014; 7:11 AM ET

Thursday morning

Here is the video forecast, showing why the Middle Atlantic region will have a warmup going into the weekend, but all of the Great Lakes and Northeast will have a cold period after that.

During warmer-than-average weather in winters past, we have frequently taken a look at the upper stratosphere for any signs of a reversal that would signal a change to colder and stormier weather. We saw this winter that such a setup is not at all required to have a cold, stormy period. There has been a strong vortex near the North Pole at the 10 millibar pressure level all winter; 10 millibars is just one percent of the typical pressure down here where we live.

But now, just as many of us look forward to warmer times, a high stratospheric reversal has occurred over just the last 10 days. You can see the difference on this map:

Studies have shown that, in a statistically significant way, such a reversal precedes a high-latitude blocking pattern that forces the jet stream southward. The signal may not be as important in spring as in winter, but if we do get the blocking and southward shift in the jet stream, it would suggest chillier-than-average conditions for the North Central and Northeast states, and perhaps stormier weather. Farther south, an increase in temperature contrast and storminess could mean more severe thunderstorms. As always, it will be interesting to see how all of this plays out.

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com

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About This Blog

Elliot Abrams
Elliot Abrams from AccuWeather.com offers this Northeast Weather Blog for the U.S. with regular updates on NE weather from a leading forecaster and meteorologist.