Major Northern Hemisphere Cold Snap Coming

December 2009
by Anthony Watts

Cold event setups in atmospheric circulation patterns are aligning. Two days ago I brought to your attention that there was a strong downspike in the Arctic Oscillation Index and that the North Atlantic Oscillation Index was also negative. See The Arctic Oscillation Index goes strongly negative

Yesterday, Senior AccuWeather meteorologist Joe Bastardi let loose with this stunning prediction on the AccuWeather premium web site via Brett Anderson’s Global warming blog:

What is facing the major population centers of the northern hemisphere is unlike anything that we have seen since the global warming debate got to the absurd level it is now, which essentially has been there is no doubt about all this. For cold of a variety not seen in over 25 years in a large scale is about to engulf the major energy consuming areas of the northern Hemisphere. The first 15 days of the opening of the New Year will be the coldest, population weighted, north of 30 north world wide in over 25 years in my opinion.

The Climate Prediction Center discussion for their forecast also concurs with both of the above:

THE AO INDEX WHICH RECENTLY HAS BEEN VERY STRONGLY NEGATIVE IS FORECAST TO INCREASE SLIGHTLY IN VALUE BUT REMAIN STRONGLY NEGATIVE THROUGH DAY 14. TODAYS BLEND CHART INDICATES BELOW NORMAL HEIGHTS ACROSS ROUGHLY THE SOUTHEASTERN TWO-THIRDS OF THE CONUS, AND ABOVE NORMAL HEIGHTS OVER THE NORTHWESTERN THIRD OF THE CONUS, CONSISTENT WITH A STRONGLY NEGATIVE AO.

Here are two of the CPC forecast maps for the days covered by Bastardi’s forecast. It is fairly typical to see an above average temperature in the west when we get a cold deep jet stream in the east:

I was going to include some Met Office forecasts here but after trying to find something useful at their web site and failing to find anything, I gave up looking.

If you live in these areas: bundle up, stock up. Get ready.

Source: http://wattsupwiththat.com