This blog is for the whole Nation but I posted in the Midwest since this is where models are differing :
In the image above we see two different outcomes...the left is the European and the right is the GFS mean. Clearly we can see the big difference is the handling of two features. The vortex over the Arctic Circle and the vortex in Baffin Island. The European continues to support the cold stratosphere with the powerful Arctic vortex and thus leading to stronger Baffin Island vortex making a pattern less susceptible to height rises in the Upper Midwest being shown on the GFS mean. Lets go one step further:
We are currently in phase 2 and models are showing a hook to the left heading towards one, but the European is less impressed and brings it into phase 3 in the long range while the GFS mean wants to take it to phase 1. The differences match up pretty well with the image posted first to the mjo phases. Notice below average temps compared to above average temps across the Upper Midwest. In addition the deeper trough idea for the Eastern US would represent the slightly below average temps into the Carolinas and Southeast.
A look at the current IR SAT imagery across the Western Pacific/Indian Ocean show two things that are going against the GFS. A clear eastward movement in the MJO has been seen over the latest SAT imagery's with convection expanding across the South China sea on eastward and decreasing across the Western Indian Ocean. It still has a phase 2/3 look which is right where we are at currently, but trends suggest this shift towards 1 should not last long. As a result I am heavily favoring the MJO phase 3/European over the GFS.
- GFS shows ridging across the Upper Midwest extending into Canada with above average temperatures dominating across much of the Nation. Some relief would be seen in the Eastern US with near normal to slightly below average if the GFS verifies. However it brings the MJO back into a phase 1 which appears very unlikely.
-European is more aggressive with the MJO and as a result we do not see the vorticies relax in the higher latitudes resulting in a continuation of the heat across much of the East with some relief in the Upper Midwest/SW CONUS.
James...with an El Nino and a very active southern stream returning the chances for snow in Rochester, TX are going to be very high with the active pattern. Check back for our winter updates and we will keep you updated throughout the winter on snow chances.