Big pattern change still expected 

Posted: 9:13 am Wednesday, November 29th, 2017

By Kirk Mellish

You know it can’t last forever, the unseasonably warm weather. As I’ve been tweeting and blogging about for some time the signs of change have been growing more consistent over the past couple weeks.

There is now strong agreement among the models as well as analog tools for a jet stream pattern reversal as shown in previous post.

If the global configuration goes full tilt then weather extremes will eventually evolve over the next month in various parts of the northern hemisphere.

Nothing too extreme expected here just yet, but it bares watching longer term.

It’s not surprising given we are entering the winter season, and after a long period of mild and benign weather the “rubber band theory” often kicks in, such patterns can only stretch so long before snapping back. AKA, the pendulum swings.

The CIPS Analog tool from Saint Louis University shows the flip:

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The WxBell American and European model ensemble charts show it stays a long while, but I am not yet convinced of the staying power for the deep south anyway:

cfs_anom_t2m_conus_2017112806_t45Screen Shot 2017-12-01 at 9.35.56 AM

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The latest ECMWF weekly output shows below-normal temps in Georgia through December 19th.

“Zonal flow” West to East bringing mild air off Pacific Ocean now:

Screen Shot 2017-11-30 at 6.27.25 AM

But PNA ridge out West with deep trough and possible midwest/mid-Atlantic/NE winter storm brings a change of air mass from North of Alaska and Canada late next week and beyond:

Screen Shot 2017-11-30 at 6.32.54 AM

EPS:

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GEFS:

Screen Shot 2017-12-01 at 9.44.20 AM

Again, I do NOT currently expect snow in Georgia the next 30-days, as of now. But you never say never in this business.

In the Southeast U.S. DECEMBER is expected to average drier than normal with temperatures slightly below-normal on average. That is the 31 day mean, not every day or every week.

Follow me on Twitter @MellishMeter WSB.

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