Winter 2022-2023

[Clarksville Snowman]

I have been watching long range looks. Hopefully this year we get some big time blocking. A -NAO is looking better and better down the line. Hopefully we will pop a +PNA or the -NAO overwhelms the overall pattern. A -NAO and a neutral or slightly negative PNA can sometimes work well too. I am pulling for things to cone together. We are in the south and winter is like a box of chocolates you never know what your going to get. I do like the dec 10 - mid January time frame. Here is a toast for a snowy Tennessee winter!!!!

[Curt]

Northern hemisphere snow cover is setting all time high records since being studies in detail since the mid 1960's. Russia is completely covered in snow which is super early. This should be interesting for later in December.

[Bruce]

Northern hemisphere snow cover is setting all time high records since being studies in detail since the mid 1960's. Russia is completely covered in snow which is super early. This should be interesting for later in December.

but be fair, when is Russia not covered snow during  winter period , happens early there .

[Curt]

but be fair, when is Russia not covered snow during  winter period , happens early there .

No, its much earlier than usual. Canada is almost snow covered as well. Some folks speculate that ash from the Tonga eruption last year which has finally made its way to the trop/strat above the north pole is perhaps a contributor. Early snow cover is also leading to the ridiculous negative AO/NAO combo coming up over the next few weeks. AS the PNA relaxes, it's possible to unload cold air in a large chunk east of the Rockies at some point or perhaps just keep things consistently cold. Most long-range models seem to lock on to this idea in mid-December. It's been a long time with a negative NAO/AO combo - maybe since 2010-2011.

[Nashville_Wx]

Well helllloo. December could be very interesting!

[Bruce]

Well helllloo. December could be very interesting!

yeah , Santa May show up on Christmas Eve night

[Coach B]

Well helllloo. December could be very interesting!

Pretty good free update from BAM wx:
https://youtu.be/u_psbYi9Y9I

[Thundersnow]

Pretty good free update from BAM wx:
https://youtu.be/u_psbYi9Y9I

Good stuff.

[StormNine]

No, its much earlier than usual. Canada is almost snow covered as well. Some folks speculate that ash from the Tonga eruption last year which has finally made its way to the trop/strat above the north pole is perhaps a contributor. Early snow cover is also leading to the ridiculous negative AO/NAO combo coming up over the next few weeks. AS the PNA relaxes, it's possible to unload cold air in a large chunk east of the Rockies at some point or perhaps just keep things consistently cold. Most long-range models seem to lock on to this idea in mid-December. It's been a long time with a negative NAO/AO combo - maybe since 2010-2011.

The volcano is probably a good factor, but in addition, I think having 3 La-Nina's in a row may have helped to reload the arctic somewhat as well and rebuild the cold source.  I am thinking a combination of both could be at play here and is helping offset the modern warming effect.   

[Bruce]

Major signal of a big winter storm on east side of Rockies mid December …

[Clint]

Welcome to the 1st day of Meteorological Winter. Here's CPC's outlook for December.

[StormNine]

That CPC outlook would be fairly favorable for a wintry overrunning event at some point in KY and at least north of I-40 in TN.

Most of your major winter storms occur near that boundary of the solid cold air.

The Cascades and the Sierra Nevada Mountain region over into the Cottonwoods of Utah would do pretty nice in that pattern as well.     

[bugalou]

No, its much earlier than usual. Canada is almost snow covered as well. Some folks speculate that ash from the Tonga eruption last year which has finally made its way to the trop/strat above the north pole is perhaps a contributor. Early snow cover is also leading to the ridiculous negative AO/NAO combo coming up over the next few weeks. AS the PNA relaxes, it's possible to unload cold air in a large chunk east of the Rockies at some point or perhaps just keep things consistently cold. Most long-range models seem to lock on to this idea in mid-December. It's been a long time with a negative NAO/AO combo - maybe since 2010-2011.

As some of you know I am a bit of a Geology nerd too. Volcanics over the planet have been more active than normal over the past 18 months with some major notable events, Tonga being one of the biggest ones. That event was gigantic in scale and the biggest we have seen in decades.  That said, its a little unusual as most of the eruption was under the surface of the ocean.  Most long term climate cooling volcanoes create is from the sulfur dioxide gas (SO2) released in eruptions. This combines with water vapor to make sulfuric acid in the atmosphere. When it gets in upper altitudes, it is a potent solar heat reflector. That said, Tonga produced very little of SO2 because of its under water nature. What it did produce en masse though is water vapor, a hugely anomalous amount. Water vapor is a greenhouse gas, but can also cool the atmosphere through more effective ocean heat transport via the weather. Australia saw this first hand already with all the winter flooding which was almost certainly related to Tonga. It also can have some cooling effects when its trapped in the stratosphere above the tropopause and can take a while to settle out.  There is also the ash injected into the stratosphere as Curt mentioned.  It will be interesting to see how it pans out because it was an unusual volcano with mechanisms occurring that have very little study as most undersea volcanoes are not energetic enough to vaporize the entire water column above them when they erupt.

Then there are the Hawaiian and La Palma volcanoes. While they were nearly not as powerful, both did release an anomalously high amount of SO2 over a long duration (especially La Palma). It's going to be interesting to see if any of these events have a marked effect on the winter.  The timing is right as it takes several months for all the products to mix globally in both hemispheres and start affecting weather.  It may not matter, but there is a high degree of uncertainty about it due to lack of data and the fact you are dealing with an intersection of the sciences in meteorology and geology.

[snowdog]

Wonder how close we, in middle TN, are to recording the warmest met winter (Dec-Feb)? We have to be close.

[Michael]

Edit: Meant to post this in Feb thread. My bad.

18z GFS is doubling down for March 3rd. 12z had it. 18z added to it.




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