Could The Polar Vortex Collapse Like January 1985?

I have been calling for a polar vortex breakdown and possible collapse for a while now, and I now think it is time to introduce the possibility that January-February 2012 could resemble the infamous January 1985.

We'll start with a flashback to December 1984, image courtesy of weatheradvance.com. In December 1984, we saw strong high pressure to the north of Greenland, along with low pressure stretching across the Atlantic and low pressure in the Southwest. High pressure also prevailed across the Gulf of Alaska, and low pressure was present in the Bering Sea. I want you to keep an eye on that low pressure in the Southwest and high pressure in the GOA for our next image.

This is what the GFS Ensembles showed as of this morning's 12z run at initialization, also known as Hour 0 in the forecast. We see high pressure trying to squeeze into the Gulf of Alaska, low pressure in the Southwest and slight high pressure in the Pacific Northwest. Looking back at the first reanalysis image of December 1984 we find a similar small signal of a high pressure in the Pacific Northwest. Worth noting is the presence of strong high pressure across north Asia, in a very similar position to the one seen in the reanalysis image. Low pressure does not extend across the entire Atlantic, but let's not worry about that specific piece right now. We have now established a few good links to December 1984.

This reanalysis image, once again from weatheradvance.com, shows what the month of January 1985 was like as a whole. We saw high pressure dominating the northeast Pacific, low pressure in Asia, and a strong high pressure regime in the Arctic, which appears to have been a base for the exile of the polar vortex. Low pressure was found in the Plains and general North US as the polar vortex was displaced south.

Here's the strikingly scary part- the long range forecast from the GFS Ensembles closely resembles this reanalysis image. We see high pressure in both the northeast Pacific and north Atlantic. Low pressure is present in the Bering Sea and Eurasia. A triangle of high pressure systems from the Pacific, Atlantic and Arctic shows that we are once again looking at a potential exile of the polar vortex. Look closely at the US. Slight low pressure is forecasted in the North US in an eerily similar move to January 1985. The center of the polar vortex, placed west of Greenland and shown as several ovals, is in almost the exact same spot as the polar vortex in December 1985, once again shown as several ovals.

This is a perfect situation for the polar vortex to slip south- the atmosphere is practically rolling out the red carpet for the polar vortex to dip into the United States. With the triangle of high pressure barricading off Europe and the Pacific as possible exit points for the polar vortex, a lack of high pressure in North America is essentially a welcome mat. Low pressure does not go towards high pressure.

Let me set the record straight- I am not calling for another January 1985. What I AM saying is that signs are pointing to a SIMILAR set-up as January 1985. That in NO WAY means the polar vortex will once again slip south- it means the potential is there, but NOT CERTAIN.

Andrew