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Pattern January 2020 - Operation Thaw Alaska

FWIW the EPS ensembles say the +PNA is here to stay for a while. Consensus actually grows through the end of the run and I’m guessing 90% of the members have a pretty positive PNA by the end of the run with some of those members frigid. I’m sure the mean is glorious for 360hrs.

We’ve been faked before, so it is what it is, but at this point it’s beautiful.
 
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That LP in NE where we would love to see a HP is really jacking this up
 
The EPS has some idea of a storm system. Note this is -3day totals.
Although most members are to the north, that would be due to temps.
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Here is a Meteogram for KINT- Smith Reynolds Airport (Winston-Salem Forsyth County NC)
from a member perspective, just a few onboard. ecmwf-ensemble-KINT-indiv_snow-9694400.png
 
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Having a +PNA only is perfectly fine for getting a winter storm around here. ~10% of winter storms in NC (since 1948) coincided w/ a +PNA/+EPO/+WPO/+NAO. Also worth mentioning that of these 4 indices, the PNA by itself constitutes about 2x as many winter storms as any other index on its own. Also, the times that only one of the 4 indices (PNA, EPO, WPO, or NAO) were favorable (thus -EPO/-PNA/+WPO/+NAO, -WPO/+EPO/+NAO/-PNA, etc.), nearly 50% of those cases featured a +PNA.

January 16-18 2018 is a good, very recent example of having an unfavorable NAO, WPO, EPO, & no 50-50 low, yet +PNA by itself was more than enough to produce a really nice winter storm in NC.




January 16-18 2018 NC Snowmap.png


The pattern being modeled at day 11 on both the GEFS & EPS certainly bears some decent similarities to Jan 16-18 2018.

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Starting to stretch the tPV day 12+. Long ways out there but it's nice to see., All the global ensembles agree on this more or less.

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As you and most here know, we've been badly fooled numerous times this winter. So, whereas I'm always hopeful for a true cold dominated pattern finally getting here (and do expect that to actually start ~late Feb) and a cold looking EPS always excites the heck out of me, I'm not betting on it earlier than late Feb regardless of what the models are showing due to their horrible performance when it looks favorable for cold, especially until the indices overall get better. Fool me once, shame on you. Fool me twice, shame on me. Fool me over and over, ...........

Hopefully, we won't need to wait til late Feb. Any earlier would be a huge bonus to me since I've not been expecting it. The MJO staying within or near the COD (a quick low amp 5) instead of going for another long, high amp 4/5 could only help imo.

With the current +AAM, maybe it will be different this time, especially if it lasts?
 
With as much skepticism that's being hurled towards the favorable pattern being modeled in the longer-term, it's not like the basic state forcing won't be favorable for it this time. Unlike in the first half of winter, east Indian Ocean convection at this time of the winter (late January onward) actually favors cold & troughiness in the eastern US and this is precisely what the EPS is forecasting in early February.


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Phase 2 MJO regressed 200mb height anomalies centered on February 10th.

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With as much skepticism that's being hurled towards the favorable pattern being modeled in the longer-term, it's not like the basic state forcing won't be favorable for it this time. Unlike in the first half of winter, east Indian Ocean convection at this time of the winter (late January onward) actually favors cold & troughiness in the eastern US and this is precisely what the EPS is forecasting in early February.


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Phase 2 MJO regressed 200mb height anomalies centered on February 10th.

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Personally, I think once the forcing returns back to the Maritime Continent, we may see a return to a milder pattern (~mid Feb (ish)) but that remains to be seen. Fwiw, you can see the seeds of our favorable pattern's demise being sewn at the very tail end of the 12z EPS w/ our nice trough over the central North Pacific disintegrating, hinting at retrogression of our west coast ridge back to the NE Pacific (thus -PNA? (again))
 
Personally, I think once the forcing returns back to the Maritime Continent, we may see a return to a milder pattern (~mid Feb (ish)) but that remains to be seen. Fwiw, you can see the seeds of our favorable pattern's demise being sewn at the very tail end of the 12z EPS w/ our nice trough over the central North Pacific disintegrating, hinting at retrogression of our west coast ridge back to the NE Pacific (thus -PNA? (again))
Heads or tails?
In all seriousness, late Feb has potential for places well north of Hogtown ... now whether y'all get anything then is a heads/tails proposition on January 22nd ...
 
Maybe it’s just me but it’s hard to get even remotely excited about that system late week next week that’s showing on the GFs . It’s not like it’s in the upper 30s and we just need a little temp help .
It’s mid to upper 40s for most verbatim . I’m more interested in the first week of February when the PNA looks to go positive . The 12z euro was headed in the right direction with the trailing shortwave . But it’s a long ass way out there
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Maybe it’s just me but it’s hard to get even remotely excited about that system late week next week that’s showing on the GFs . It’s not like it’s in the upper 30s and we just need a little temp help .
It’s mid to upper 40s for most verbatim . I’m more interested in the first week of February when the PNA looks to go positive . The 12z euro was headed in the right direction with the trailing shortwave . But it’s a long ass way out there
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edb50bf4faf95b9a3b512e2bf38040d8.png



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It's not just you. We've been chasing these turd duds all winter. It's all we've got, I guess, but this one is likely going to swirl around the toilet bowl too, unless it can find a magical way to get much stronger. I mean, I wouldn't rule out some wet flakes on the NW fringe, but that's about the extent of it, IMO.
 
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Ive always said that a + PNA is the higgest most favorable signal for the SE to root for. The mac -daddy of them all. Thanks Webb for those stats.

This is especially the case for folks like @pcbjr and myself in the deep SE because the correlation to cold is highest the deeper in the SE you are per charts I've seen.
 
Maybe it’s just me but it’s hard to get even remotely excited about that system late week next week that’s showing on the GFs . It’s not like it’s in the upper 30s and we just need a little temp help .
It’s mid to upper 40s for most verbatim . I’m more interested in the first week of February. The 12z euro was headed in the right direction with the trailing shortwave . But it’s a long ass way out there
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edb50bf4faf95b9a3b512e2bf38040d8.png



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Surface temps are highly dependent on the interaction between the various shortwaves triggering this surface low, and the feedbacks between the nature of the phasing between those s/ws alters the strength & placement of the surface low which influences the amount of dynamical cooling and cold advection on the backside of the low and that causes variations in surface temps. While the model on this particular run shows upper 40s-50F, we actually don't know anywhere near enough information to assume that's going to be the case given the aforementioned statement(s).

Even the inner quartile range on the often underdispersed ensemble suites (like the EPS) is 6-7F & upwards of 10F+ in places. It's totally reasonable to assume we could be in the 60s (perhaps w/ thunder) or as cold as the mid-upper 30s w/ the possibility of wet snow. I'm not saying a cold/snowy solution is by any means probable-likely (it's almost certainly very unlikely atm), but rather I'm saying don't jump to conclusions about exactly how far we have to go wrt surface temps based on a single or a few operational model runs. Cold rain is by far & away the most likely solution atm but it's not set in stone either.

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It's not just you. We've been chasing these turd duds all winter. It's all we've got, I guess, but this one is likely going to swirl around the toilet bowl too, unless it can find a magical way to get much stronger. I mean, I wouldn't rule out some wet flakes on the NW fringe, but that's a out the extent of it, IMO.
Patience RC! You’ve got to set the table before you can feast!AD0A6CB8-3CB5-4DEC-AFAF-618A66ABCC59.png
 
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