We’re all now beginning to cast our eyes out and towards the autumn and eventually winter season as summer 2012 enters it’s final meteorological month. I intend to keep checking back with the model long range runs and show you and explain what’s going on and where I am going with my forecast which will be issued at the end of October. I will share with you step by step the evolution of the changing season.

The current Jamstec model continues to show a very cold looking autumn across the majority of North America with Alaska as the source. The cold this summer over Alaska and all the way down the North American west coast identifies the cold PDO, the horseshoe of cold in the Pacific. This cold over the NW and WC of the continent will eventually chip away at the heat over the Plains into September.

The flip is possible with El Nino’s coming on and boy, what a flip it would be. It’s very plausible that we see a snap in this hot, dry pattern by the time we reach the later stages of August which sets the tone for a cooling trend through September. A cold October given the evolution of a weak to moderate Nino, is quite likely.

As for the UK and western Europe, I can see how a warm autumn looms but with a cold spell perhaps early in October. Notice the cold covering all but the UK over Europe!

There are similarities to 2009 which saw a tanking of the NAO during July with a spike later in summer. If this occurs this year then the NAO may bounce enough to give us a week or so of warm and settled weather perhaps not unlike the end of May. That is something I will look deeper into and share more.

Tags: autumn 2012-13 forecast, fall 2012-2013, long range forecast for usa