Conditions Far Different This December vs December 2015

The conditions over the higher latitudes at 10mB (65-70,000 feet) are much warmer recently than last November/December...

Hat tip: Peter Mullinax

 ...which translates to higher heights aloft at 10 mB.

Pressure pattern completely the opposite of the polar conditions in early December last year where heights were much lower. Polar vortex was very stable probably influenced by the El Nino.

 Temperatures last December were well above normal across the eastern 2/3 of the US

In fact, over the last 6 Decembers, only 2013 and 2010 were below normal east and/or north.

So far, temperatures in early December through the 5th were above average.

Based on the high latitude conditions at 10 mb (65 and 70,000 feet) mentioned above and the higher than normal Eurasian snow cover which has driven skyrocketing high pressure across Russia, this first shot of colder air across North America was not a surprise.

Nearly Record Setting High Pressure Across Asia in late November

Graphic courtesy Greg Carbin, SPC

In fact, we mentioned this in our winter weather outlook issued back on October 27th and in subsequent tweets on November 22nd and Dec 2nd emphasizing a significant lake effect snow event a week in advance:

The CPC painted its first below normal temperature outlook across ALL of North America for the first time since December 2013. Hat tip: Brian Brettschneider

We haven't had a December with temperatures at least one degree below normal in Cleveland since 2010.

A few days ago (December 6) I retweeted a post from late November highlighting the shifting jet stream position across the middle of the US allowing more frequent storm systems.

Our 8day forecast issued on December 7th and 8th shows these individual systems with high snow potential for northern Ohio through December 16th and beyond.

Anticipate below normal temperatures, overall, the rest of December 2016. 80% Chance for a white Christmas for northern Ohio!

Winter Pattern Unrelenting: More Arctic Cold

Our winter weather outlook back in late October featured a below normal temperature (much colder winter) with above average snowfall.  Given the weak central based El Nino, cool pool in the northern Pacific, warmer west coast and warmer east coast, a stronger southern jet stream phasing in with the polar jet to the north driving big snowfalls from nor'easter type storms in New England shouldn't be surprising.

The areas of the ocean that went into our winter outlook are circled in red. All pointed to colder than normal temperatures in the east.

This is different from last winter when the warm west coast cool of ocean was located in the north central Pacific near the Gulf of Alaska. The central based El Nino (Modoki) hadn't developed yet.

I want to emphasize that these warm and cool pools aren't and weren't the only drivers of our last two winters. But they are significant. Here was our initial best match as we formulated out winter weather outlook (December through February temperatures) back before Halloween.

The overall pattern remains very cold. More cold this weekend--Polar Vortex type cold!

Well below zero across much of the northeast Friday and especially Sunday morning. Even Florida will see lows in the 20s Sunday morning (February 16th) from Jacksonville to Pensacola. The orange crop might take a hit!

Below zero wind chills will reach northern Georgia and the Carolinas with -20 to -30 chills across the Great Lakes.

Here we are in mid February when the cold usually starts to retreat as the first pushes of spring emerge across the deep south. Will the cold air break sooner or later?

The often overlooked Canadian model shows the trough east/cold east continuing through the end of the month. The other models show this too.  However, the trough is retrograding back west a bit. This would shift the cold into the Great Plains by the end of February.

Cold Pattern thru end of February

In droughts, extremely hot conditions will feed off of the extremely dry air above the dry ground. This creates more evaporation which feeds the heat. This chain reaction is very hard to break. In perpetually cold patterns like this, the drivers are very strong and very difficult to break. The cold air can feed the upper air pattern reinforcing the trough in the east and cold/ridge and warmth in the west. In essence, the overall pattern remains stuck.

Good news is that heading into March even during the coldest Marches in Cleveland, 60+ degree warmth shows up by the middle of the month.

That said, the southern branch of the jet becomes very active in March. This could lead to a few more panhandle type storms in March which always have potential for reach Ohio.  Stay tuned.