Monday, January 2, 2012

Major Snows for the Country Not Out of the Question

The pattern is changing. At this point, it's quite obvious. Something people haven't examined closely (including myself), is what this changing means to the weather pattern. In a graphic, here it is.
This still has a lot of sorting out to work through, so as of right now, don't hold me to this.
Using some information we received from former Accuweather Chief Long Range Forecaster Joe Bastardi, combined with some of my own research, it has been determined that this pattern may set up from a positive PNA. Here's the positive PNA.
This positive PNA has two factors: the Siberian Express and the Pineapple Express. The first one is the Siberian Express. We can see the area of cold that is present in the Plains and Midwest. This cold air is exported from Siberia into the USA. On the other hand, we have the Pineapple Express- areas of high water vapor that create storm systems that wash ashore the West Coast with potentially devastating flood effects. That is the big arrow you see arcing over the high pressure system. So far this winter, that Pineapple Express has been unable to form, as a major trough in Alaska has prevented it. But now, with the very unstable polar vortex and interfering ridges breaking the polar vortex, we may see this ridge form yet. Now, when these systems come onshore, they are directed sharply southward due to the Siberian Express. Thus, the storms go down south, grab ahold of some Gulf moisture, and produce some big-time snows for the Midwest, Plains and Northeast. All of these elements have to be present for this to work out. Here's the thing though- barely any ensemble members are showing the PNA to go positive. In fact, many show the PNA to go negative. That is bad news for snow lovers.
What these models may not be recognizing is the breaking polar vortex. They may just not realize that this vortex is breaking. It is breaking, and to me,t he chances of the vortex reforming to its past strength is becoming less likely. That unlikelihood is shown by the NAO and AO forecasts, which are forecasted to be going into a negative phase- an indicator of a breaking polar vortex.
All in all, I just don't think these models are handling the PNA or the polar vortex well. Even right now, there is a ridge breaking into the polar vortex. I'm not seeing what is wrong with the forecasts if the observations show the vortex breaking. Models are supposed to take in observations at initialization (the very beginning of the model run). But hey- the models might be completely right about the PNA.
Either way, we know a couple things:
•The Polar Vortex is at least weakening.
•From that, the AO/NAO should begin to trend negative.
•A negative AO/NAO would provide cold and snow.

Sometimes an index can be unfavorable for snow and another one can be favorable, and the favorable index wins out. It's a big educated guessing game- key word educated.
We will have to see. This is a very interesting development, though, and is something that should be watched.

18 comments:

Anonymous said...

When do you think the first blizzard for the Great Lakes would be?...AJ

Eddie said...

Would Detroit get snow from this system that will stick. And also when do you see the pattern change happen for good like a positive PNA And negative AO/NAO

Mike Paulocsak said...

Hello Andrew.If the polar vortex breaks,does it really matter what the PNA states.Like you mention in your post,maybe they don't recognize it.I hope i didn't confuse you.Do you believe we could get in a colder & snowier pattern by mid-jan.?

Anonymous said...

When for Chicago we need some snow

Andrew said...

Anonymous #1: We cannot predict blizzards.

Eddie: There will be multiple systems possible. The pattern change is happening right before our eyes as the polar vortex breaks.

Mike: It can matter what the PNA says, but the polar vortex break is a very big thing. I believe the models do recognize this in some state, maybe not fully. We will b getting in a colder pattern in Mid january.

Anonymous #2: Snow should come soon.

Anonymous said...

Sorry, I should have known. AJ

Anonymous said...

Andrew does this mean storm will start to break loss now for Great lakes?

Anonymous said...

It won't let me enter CIRRUSWEATHER.COM. AJ

Andrew said...

AJ: It's OK.

Anonymous #1: The Great Lakes will be getting some storms if this comes through.

Anonymous said...

charlotte nc is not in this?when will charlotte get snow we need some

Mike Paulocsak said...

Hello Andrew.Do you think if this comes to pass,the whole country should start seeing more frequent snows?Hopefully in the coming days the models start to see this and come to an agreement with each other.

Ben said...

Kansas City Missouri in line for some of these snows?

Andrew said...

Anonymous: Watch the first couple weeks of January.

Mike: If this happens, the pattern is basically changed.

Ben: Possibly.

Eddie said...

Andrew what are your predictions for the rest of winter for Detroit below average temps or above average Temps and same for snow above or below

THANK YOU

Anonymous said...

Adjust your map to favor the Northwest through Midwest and you've got the negative PNA taken into account. If the PNA is positive, it just means that the east coast won't get snow, not the entire country east of the Mississippi. In fact, Chicagoers should actually want a negative PNA.

Andrew said...

Eddie: Detroit should end up with normal or below normal temperatures as well as some abOve normal temperatures, possibly.

Anonymous: Thank you for the heads up.

Anonymous said...

DO U THINK MAYLAND IS IN FOR SOME SNOW SO SOON?

Andrew said...

Yes.