Thursday, December 29, 2011

Signs Appearing that +AO/+NAO Regime May Break

Initial 0z ECMWF 500mb Analysis
Above we have the initial 500mb heights analysis from the latest 0z ECMWF. We see the tight polar vortex of low atmospheric pressures encircled in the black area. This polar vortex is what supports the +AO/+NAO regime. That said, if there were high pressure systems over the same black area, we would be seeing some sort of -AO/-NAO. Let's jump ahead into the ECMWF's forecast.
Hour 192 of 0Z ECMWF
At hour 192 we're seeing the Polar Vortex break apart as a ridge forces itself into the vortex from Asia. This in turn forces a low pressure system towards Greenland, making for a West Based +NAO. While we aren't showing it, this ridge does break down at the end of the ECMWF forecast timeframe. It does show that there is potential for a ridge to break in and possibly bring in some colder weather for the US.
This is another view of the top 2 images, with the analysis period at the top and the hour 192 image on the bottom of these latest 2 images.

31 comments:

LJ said...

With the colder temperatures could it bring snow with it, Andrew? Thanks.

Andrew said...

If this +AO/+NAO breaks, there would be snow/rain.

LJ said...

Thanks.

Andrew said...

Oh wait, that was a typo. I meant to say snow/cold.

LJ said...

Oh that's fine and do you know where the snow could possibly be or is it too far a out to tell? Thanks.

Mike Paulocsak said...

Hi Andrew.Let's hope we see this break and bring in the snow/cold.I'm waiting for the precip.to be in the form of snow.Hopefully this is a sign that we can start to see the MAJOR storm systems your predicting to move through the Ohio Valley.

LJ said...

Mike, that would be very nice because the pattern right now is boring, NO SNOW just rain, it's the opposite of last year.

Mike Paulocsak said...

Hi LJ.Yes that's true.Last year at this timre i had alot of snow on the ground,i would imagine you did to.

LJ said...

Yes I did have snow on the ground, around new years it melted, right now we have around 2 inches, but none of it is on the ground, it all melted.

Mike Paulocsak said...

Hi LJ.so far i have had only a trace since the beginning of this Dec.

LJ said...

The meteogram generator for my area said 1inch or so by Friday afternoon and then 1in to 2inches by very early Sunday morning, I think this is a little to high, I'm thinking an inch for both time frames.

Mike Paulocsak said...

Hi Andrew.It would be great to get a PANHANDLE HOOK right now.

Andrew said...

LJ: I'm thinking that most accumulations should stay north. But again, it depends on temperatures.

Mike: At the end of the old 0z ECMWF, i saw a strong trough entering the Southwest.

Mike Paulocsak said...

Hello Andrew.Do you think this could be a storm trying to form.If so,hopefully the temps.are cold enough to support snow.

Mike Paulocsak said...

Hello Andrew.This concerns the update concerning the stratosheric warming tomorrow.If this does hold true,could this mean that the cold would come down from Canada and stay in place so there would we snowstorms developing?

LJ said...

Hopefully it does, because I want SNOW!

Mike Paulocsak said...

Hi LJ.Could not agree more with you!I'm waiting patiently for the snow.

LJ said...

My local weatherman said in 2weeks or so we will get something in the form of snow. I was going to tell him keep it silent until the last minute so it can happen!

Mike Paulocsak said...

Hi.LJ.Did he mention a big storm?Also,did he mention who would be affected?It's not lake effect is it?

LJ said...

He mentioned if the NAO goes negative in a La Nina we will get quite a bit of snow. He did not mention any big storm and nothing about LES. If you want to see for your self go to wrex.com/weather and then click the blogs icon.

LJ said...

He said big snows are in our outlook beyond 2 weeks

LJ said...

''Our'' is probably talking about Rockford,IL and surrounding areas.

Mike Paulocsak said...

Hi LJ.I just looked this up.This looks like it could verify.Maybe Andrew would notice this.

LJ said...

While at least it's not out of the question, we will get snow, but we don't exactly know when.

Mike Paulocsak said...

Hi LJ.Exactly.It will happen sooner or later.You would think when the NAO does go negative,the areas that have seen substantial rain recently would get hefty ammounts of snowfall.Both you and i have seen a TON of rain since the beginning of Dec.Where i'm at in Ohio,we aree about 15" above normal for the year in the rainfall department.I live in Holmes county Ohio.I live in the country.The nearest town is called Holmesville Ohio.It's a very small town.I think you and i are the only ones that come here and visit this site and post comments.I'm sure Andrew doesn't mind.

Andrew said...

LJ: Thank you for posting the WREX item- it will help us define the NAO in our pattern change update today.

Mike: I most certainly do not mind if people want to chat on here.
We are trying to see if we can get one of those chat boxes that we could put on this blog's sidebar for easier chats, but that prospect isn't exactly 'moving forward' if you get my drift.

Mike Paulocsak said...

Hello Andrew.Thanks.I will be waiting on the updated weather pattern change.About the blog's sidebar,i personally like the way you have it now.This is great the way it is now.

LJ said...

Yep Andrew, I agree with Mike, leave it the way it is.

LJ said...

On WGN in Chicago this morning, they said the same thing as WREX, it will be interesting and payback time from all the rain we got.

LJ said...

If the sidebar thing does get going maby use it during severe weather or winter storms, Andrew.

Mike Paulocsak said...

Hi LJ.I'm MORE than ready for the payback for heavy snow!Let's hope it includes the midwest and Ohio valley both.Both had an abundance of rainfall recently.You would think we would eventually get heavy snow after the heavy rain we had if the storms still do move through like they did with the rain.