Friday, December 16, 2011

ECMWF Ensembles Picking Up on Pattern Change with Positive PNA

The ECMWF Ensembles are picking up on the long-awaited pattern change by displaying the typical PNA index in its positive phase, as shown below as well in 500mb heights.
Typical Positive PNA 500mb heights in January.
A positive PNA features a trough in the East and a ridge in the West. Putting that in simple terms, a positive PNA means many low pressure system occurrences in the East and many high pressure system occurrences in the West. As the stratosphere warms, it is only fitting that the PNA, AO and NAO (all 'essential' for cold air and snow for the East) will be turning into much more favorable phases. January could be, and likely will be if everything goes right, THE month for this winter. February could be snowy as well, but January will really start cranking the snow machine.

Side note: For those seeing my exaggerated feelings on this winter or this storm, I am a snow lover, and, no matter how hard I try to avoid sending those feelings on here, they do get on here. Winter is typically a turbulent time for my emotions and patience with storms and winter overall, so y apologies in advance if I start to go overboard.

11 comments:

Anonymous said...

So this means winter is really going to start here soon?

Mike Paulocsak said...

Hello Andrew.I'm the same as you when it comes to snow.I get really edgy when winter storms develop.So you think this January and February could be the the time we should start to see some decent storms to develop? I'm really hoping that my area in Ohio where i live in Holmes county recieves some heavy snow.As i look at the low positioned south of Ohio,could this bring my area some heavy snow? My local forecasters in Cleveland have mentioned the same thing you mentioned in this post.Also,the NWS in Cleveland is predicting the same thing.Sorry for the long post,i'm just excited to read this.I hope you understand.

Anonymous said...

Andrew, We appreciate all of your efforts and can relate to your feelings. Thank you for an interesting and informative website.

Andrew said...

Anonymous #1: It is looking that way.

Mike: JAN/FEB is now positioned as the time for winter to be in its 'primetime'. Ohio could very well get some heavier snow from this system, depending on strength and track of this storm.

Anonymous #2: Thank you for the kind words. I do appreciate them.

Eddie said...

Will you be revising the winter forecast and do you think in January and February Detroit will get above normal snow

Anonymous said...

One day saying winter will be a disappointment and the next day saying it will start soon. Not trying to be rude or anything, but you shouldn't jump on one model run and exaggerate the long term impact it will have. They are usually generally correct, but they are wrong sometimes in the short term. But I love winter as well so I understand you. Just got try to resist getting overly excited when one model run does good for your area (and vice versa). Tomorrow afternoon, I will start paying much more attention to the models and I hope this storm can lay down a few inches in places (say from southwest Kansas northward to northern Ohio).

Mike Paulocsak said...

Hello Andrew.Do you think that the gulf of mexico will be open for business with this system? What i mean is a lot of moisture being pulled into it.If this were to happen,it would be a pretty good snow maker.

Andrew said...

Eddie: We think Detroit will continue to have a chance of above normal snowfall this winter.

Anonymous: We have been using ensembles and multiple models in association with this storm. If you are going to begin looking at the models, I would start checking them out on Sunday for a more solid solution.

Mike: Yes, but then comes the problem of war air advecting (moving) farther north and thus canceling out snow.

Andrew said...

In response to Mike *warm air, not war air.

Mike Paulocsak said...

Hi Andrew.Thanks for answering my question.Is this the storm for next week or when the pattern is supposed to change in January? I'm not to sure how to read the millibar maps.

Anonymous said...

Thanks for the Good news Andrew!! I live in West Tn & we have already had 2 snows. Hope we get covered like hot gravy on a cold biscuit. LOL Thanks for all you do!!