Winter 2021/2022 - Some Preliminary Thoughts

Written on: 07th Oct 2021

I tweeted out a few days ago that I'm expecting a higher chance of cold/blocked weather during the first half of winter with the second half of winter most likely to see milder Atlantic driven patterns. Here's my current thinking as of today. I want to discuss a couple of variables.

The bias-corrected CFS forecast is perhaps one of the best I've seen in terms of early winter SPV forecasts.    

It keeps the vortex way below average through into January, most notably late November into early December where we get very close to a reversal, I tweeted a few days ago but I'm marking November 20th - December 15th for a potential Sudden Stratospheric Warming (SSW). 

The un-corrected version of the CFS is even more nuts, but given it has a huge -ve bias at longer ranges I'm really only posting this one for fun.

A weak vortex (and possible SSW) into early winter with an -QBO and La Nina almost overwhelmingly favours blocked conditions in our part of the world. The latest EC Seasonal supports this idea with a huge signal for European blocking during December.

Whether these variables translate to cold weather reaching the UK or not is a question that can't be answered until the short term, when we see patterns playing out in real time, however at this very early stage in the still very much developing forecast, late November and through December is looking very, very interesting from a coldies perspective. 

Lets see how things pan out during October, it's an important month for winter forecasting and by the beginning of November, we have a better idea on the state of the developing (or perhaps not so developed) stratospheric polar vortex.