Wednesday, November 7, 2012

Long Range Lookout: November Lost to Warmth

I believe that November is, unfortunately, lost as far as winter potential goes, as a poorly-timed Rossby Wave train begins to set in for November.

Hour 204

Hour 384
The Rossby Wave train is a 'train' of storm systems pushing southwest from the North Pole. What happens in response to storm systems pushing in the West? If you guessed a warm East US, you are correct. Hour 204 from November 6th's latest GFS Ensembles shows that scenario.

Rossby Wave trains typically have a full cycle in which 3 stages occur. Stage 1 involves the pattern in a dormant state, not really doing much. Stage 2 is when you start to pick up on some storm systems hitting the same area over a period of time. Stage 3 is the full-blown active stage, as is forecasted in Hour 204 and 384. These three stages usually happen within a 4-6 week cycle, so it's no surprise that the farthest GFS Ensemble forecasts still show the Rossby waves in action.

Because this will be developing in early November, we can expect this poorly-timed pattern to last through November, likely ending in early December at the earliest and mid-December at the latest.

But don't lose hope!

I have been tracking this Rossby wave train for a while now. If I extrapolate (use observations in a forecast) this Rossby wave train will progress into the North Pacific. In response, the high pressure tendencies will be placed over the West, leading to a much stormier, colder pattern for the East. Couple that with favorable late-winter signals from Siberia in October and it looks like we could have a more back-loaded winter coming up.



KakHome said...

The models have generally backed off of significant warmth in the East past Tuesday or so, though they aren't cold either. Do you support that there might not be another major warm up in the East, even if it's not cold either?

Also - all said and done (including the cold start), what do you project for a Cleveland departure in November?

Anonymous said...

Andrew I am liking your posts more and more. I have been telling folks for a long time that cold and snow in Nov. isn't that strong of a signal for a cold and snowy winter, sometimes it is the opposite. Ever hear of the old folk saying... "Snow in November turns to mud in December"? If this turnms out to be true then we who live in the east would have a great chance of having cold and snow in time for Christmas. Thanks for the good news Andrew.

KakHome said...

Re long range, I sent you a message as Hertz on Accuweather. Some of the models you showed have come in with different long-range forecasts in their November runs. The NCAR is concerning me.....