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Pattern January 2021 - Joyless January

Shaping up to be a special year for TN imo. Mountain areas as well. These cold frontal boundaries that push through with just a smidge of ridging down the east coast is their bread and butter. Western areas have been favored over the past several years. That will change eventually. Hoping for that change to happen later this winter.
 
Every year we wait on things like strat warning, mjo propagation, solar flux, etc. to eventually get us to a wintry pattern. And every year, no matter what combination of indexes we have or what favorable events may be just over the horizon, we find ourselves waiting on yet another back-loaded winter, hoping for those favorable things to eventually pan out. So, I guess we'll see how it goes this year. At least we have a real -NAO, even though it has been east-based so far.
 
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SD said:
I'm not even sure that qualifies as a -NAO
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It technically probably does, but effectively, it's not helpful to us. The north Atlantic ridge, like DT has always said, is usually not helpful for winter weather outside of the mountains east.
 
Rain Cold said:
Every year we wait on things like strat warning, mjo propagation, solar flux, etc. to eventually get us to a wintry pattern. And every year, no matter what combination of indexes we have or what favorable events may be just over the horizon, we find ourselves waiting on yet another back-loaded winter, hoping for those favorable things ro eventually pan out. So, I guess we'll see how it goes this year. At least we have a real -NAO, even though it has been east-baswd so far.
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I’m just looking at the positives so far, we haven’t had nothing ridgewise centered over the SE, we’ve at least had several close calls with a less than ideal pacific (which is responsible actually for the warming/strat PV attack)
That Aleutian low is actually what’s allowing the -NAO in the first place, -EPOs destroy a -NAO (which is why we end up torching after those blocks retrograde as there’s no block on top to keep in so we get ridged) all we just need is transient periods of Aleutian low retrogression/suppressed or regular +PNA and we can make something work, this pattern isn’t a blockbuster pattern but not a shutout
 
The typical pattern in nearly the past decade is we get skunked in the winter and NAO goes negative along with other indices going cold in March or April. Stayed chilly and windy until mid-May in this neck of the woods in 2020, one of the relatively small gut punches 2020 had to offer. Getting a -NAO in winter when it is theoretically supposed to be cold and we get snow is glorious. Please give me a spring in 2021 among other things. The white Christmas in these parts was awesome! Happy New Year to everyone!
 
here’s a example with a very transient period of weak +PNA you have a quick North Pacific jet extension with a quick/transient +PNA which digs some pacific energy out west behind that big New Years system, you have the marginal cold set in place, after that, it’s all about what the system does under under that ridging on top and whether it shears out or amplifies (probably won’t due much but it’s a interesting look with that coastal) a stronger west coast ridge or western central US ridge helps
You can see here with the block in place, there’s stuff in the Atlantic which doesn’t allow the southeast ridge to become a buzz saw (that almost looks interesting for perhaps a subtropical system?)
Only issue here is the WAR45E3D22F-3B5F-4B19-BD92-415AB1630766.png
 
Myfrotho704_ said:
I’m just looking at the positives so far, we haven’t had nothing ridgewise centered over the SE, we’ve at least had several close calls with a less than ideal pacific (which is responsible actually for the warming/strat PV attack)
That Aleutian low is actually what’s allowing the -NAO in the first place, -EPOs destroy a -NAO (which is why we end up torching after those blocks retrograde as there’s no block on top to keep in so we get ridged) all we just need is transient periods of Aleutian low retrogression/suppressed or regular +PNA and we can make something work, this pattern isn’t a blockbuster pattern but not a shutout
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Yeah I don't disagree to an extent. We're not torching and we don't have an extended SE ridge. But it's really not a good pattern for a winter storm either. Not technically a shutout, but it's really hard to get things to line up and get the needle threaded.

The biggest issue right now is not generating arctic highs, which propagate into the US. This marginal stuff isn't going to work, and variables that we used to observe that aligned to bring cold and snow now fail to do so as efficiently, due to a warmer climate.

We don't need a raging -EPO, but we need to seed Canada with Arctic air. We can do that and still have a -NAO. Those things aren't mutually exclusive. But so far, there's no evidence in the near term of that happening. Until it does, we will be dealing with marginal cold which much more heavily favors the Midwest, Mid-south, and mountain areas.
 
Rain Cold said:
It technically probably does, but effectively, it's not helpful to us. The north Atlantic ridge, like DT has always said, is usually not helpful for winter weather outside of the mountains east.
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We've had such a strong WAR pattern for many years now. This year so far it just seems to have moved more north. When we finally lose the WAR and replace it with lower heights, that's when I'll know we've had a real pattern change.
 
Myfrotho704_ said:
I’m just looking at the positives so far, we haven’t had nothing ridgewise centered over the SE, we’ve at least had several close calls with a less than ideal pacific (which is responsible actually for the warming/strat PV attack)
That Aleutian low is actually what’s allowing the -NAO in the first place, -EPOs destroy a -NAO (which is why we end up torching after those blocks retrograde as there’s no block on top to keep in so we get ridged) all we just need is transient periods of Aleutian low retrogression/suppressed or regular +PNA and we can make something work, this pattern isn’t a blockbuster pattern but not a shutout
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The only exception to this is when we have a legit -AO to anchor the -EPOs/WPOs to the anomalous low PV reservoir over the pole and that's what a SSWE could provide us esp as we get into the 2nd half of January & February.
 
As expected, the Pacific jet is gonna be on roids in early January following the mountain torque episode that's coming the next 10+ days.


This is really a quintessential precursor k=1 SSWE event look right here in SLP and it's something I haven't seen in this fashion and to this degree in a long time. Most of the warming events in the 2010s were splits w/ wave resonance from the N pacific & Atlantic.


1609019971226.png
 
@Webberweather53
I noticed that with the SSWE at 10mb, 10mb >> 30mb then 50mb height anomalies cool towards the tropics, could that enhance convection/perhaps impact the MJO, just thought given a cooler strat towards the tropical areas could perhaps enhance convection ? Still just trying to learn a bit more here C62AE5A0-04BA-46A6-9CE7-5F49374D000F.png3807ABF1-5DAB-4820-9C61-E1632273C3AE.png
 
Rain Cold said:
Every year we wait on things like strat warning, mjo propagation, solar flux, etc. to eventually get us to a wintry pattern. And every year, no matter what combination of indexes we have or what favorable events may be just over the horizon, we find ourselves waiting on yet another back-loaded winter, hoping for those favorable things to eventually pan out. So, I guess we'll see how it goes this year. At least we have a real -NAO, even though it has been east-based so far.
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18z's now got a low in the gulf.. Baby steps, lol.
 
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