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Pattern Freezing Ferocious February

I know some were feeling glum about the winter the past few days but it's not over til the fat lady sings, I definitely feel much better & more confident to go about saying that we could see a turnaround in late February & March given how the pattern is evolving and the fact that HM is on board with this idea. Amy Butler here just reminds us yet again that the models can't properly simulate tropopshere-stratosphere interactions and in concert w/ tropical forcing over the Pacific which favors disruption of the PV and a -NAO (with the -NAO lagging phases 6-7 of the MJO by a few weeks), the GEFS is beginning to sniff out a potentially significant -AO crash on the horizon.
Screen Shot 2018-02-06 at 11.48.25 AM.png
Screen Shot 2018-02-06 at 11.48.44 AM.png
 
Jimmy Hypocracy said:
This isn't funny anymore
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Bruh. That time period keeps getting worse temp wise. Considering while there's been lot's of back and forth between above average and below average, it hasn't gotten real warm (not really even any 70s!), that's very disappointing. That's going to feel hot to me.
 
Webberweather53 said:
I know some were feeling glum about the winter the past few days but it's not over til the fat lady sings, I definitely feel much better & more confident to go about saying that we could see a turnaround in late February & March given how the pattern is evolving and the fact that HM is on board with this idea. Amy Butler here just reminds us yet again that the models can't properly simulate tropopshere-stratosphere interactions and in concert w/ tropical forcing over the Pacific which favors disruption of the PV and a -NAO (with the -NAO lagging phases 6-7 of the MJO by a few weeks), the GEFS is beginning to sniff out a potentially significant -AO crash on the horizon.
View attachment 3833
View attachment 3832
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Good point, However, one also should be wary about GEFS AO predictions as they have been biased way too negative recently:

For example, here was the 1/26/18 GEFS AO prediction:

aoFcasrGEFS012618.gif

So, the 1/26/18 GEFS 14 day prediction had the AO to be in the -1 to -2 range about now. However, we're currently nearing +1 and rising in the shorter term meaning a miss by -2 to -3! Also, check out today's GEFS prediction:
aoFcasrGEFS020618.gif

Note the mean AO over the last 4 months has been 0.0081 or essentially 0/straight neutral. However, note the bottom graph (14 day prediction), which has been mainly negative and has averaged -0.7194. So, the 14 day prediction has had a negative bias of 0.7194 + 0.0081 or a -0.73 AO bias. So, I'm advising extra caution about GEFS based -AO predictions.
 
GaWx said:
Good point, However, one also should be wary about GEFS AO predictions as they have been biased way too negative recently:

For example, here was the 1/26/18 GEFS AO prediction:

View attachment 3834

So, the 1/26/18 GEFS 14 day prediction had the AO to be in the -1 to -2 range about now. However, we're currently nearing +1 and rising in the shorter term meaning a miss by -2 to -3! Also, check out today's GEFS prediction:
View attachment 3835

Note the mean AO over the last 4 months has been 0.0081 or essentially 0/straight neutral. However, note the bottom graph (14 day prediction), which has been mainly negative and has averaged -0.7194. So, the 14 day prediction has had a negative bias of 0.7194 + 0.0081 or a -0.73 AO bias. So, I'm advising extra caution about GEFS based -AO predictions.
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Similar to the GFS's MJO biases, these stereotypical tendencies in the GFS aren't always applicable and should not be immediately broad-brushed to every situation. In this case, I think that notion holds true because there's a very clear change in the stratosphere, tropical forcing & concomitant equatorward progression of -AAM that supports a substantial dip in the AO in the longer term, in mid-late January this wasn't necessarily the case because the large-scale forcing wasn't as favorable. Models usually don't properly simulate stratosphere-troposphere interactions and the EPS is also on board w/ a -AO surge in the coming weeks. Sure you can claim the GEFS might be overzealous in its depiction of the AO and it probably is to an extent but there's very legitimate support to a -AO stint later in the month. When you stick the MJO in the Pacific, the AO & NAO usually dip negative 1-2 weeks afterwards due to the impact of diabatic heating on the extratropical circulation pattern and wave fluxes and the PV split is only going to augment this. The support for this idea from HM only lends more confidence
eps_ao_00.png
 
Webberweather53 said:
Similar to the GFS's MJO biases, these stereotypical tendencies in the GFS aren't always applicable and should not be immediately broad-brushed to every situation. In this case, I think that notion holds true because there's a very clear change in the stratosphere, tropical forcing & concomitant equatorward progression of -AAM that supports a substantial dip in the AO in the longer term, in mid-late January this wasn't necessarily the case because the large-scale forcing wasn't as favorable. Models usually don't properly simulate stratosphere-troposphere interactions and the EPS is also on board w/ a -AO surge in the coming weeks. Sure you can claim the GEFS might be overzealous in its depiction of the AO and it probably is to an extent but there's very legitimate support to a -AO stint later in the month. When you stick the MJO in the Pacific, the AO & NAO usually dip negative 1-2 weeks afterwards due to the impact of diabatic heating on the extratropical circulation pattern and wave fluxes and the PV split is only going to augment this. The support for this idea from HM only lends more confidence
View attachment 3837
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I hope HM and you end up right as I don't want it to stay warm through the end of the month. I am assuming most of the next 2 weeks will be warm preceding what may or may not occur late month. I am keeping in mind (what MDA said) that these SSW have more often cooled Europe than N.A.
 
GaWx said:
I hope HM and you end up right as I don't want it to stay warm through the end of the month. I am assuming most of the next 2 weeks will be warm preceding what may or may not occur late month. I am keeping in mind (what MDA said) that these SSW have more often cooled Europe than N.A.
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I wonder why they have more often cooled Europe than NA ?
 
GaWx said:
Good point, However, one also should be wary about GEFS AO predictions as they have been biased way too negative recently:

For example, here was the 1/26/18 GEFS AO prediction:

View attachment 3834

So, the 1/26/18 GEFS 14 day prediction had the AO to be in the -1 to -2 range about now. However, we're currently nearing +1 and rising in the shorter term meaning a miss by -2 to -3! Also, check out today's GEFS prediction:
View attachment 3835

Note the mean AO over the last 4 months has been 0.0081 or essentially 0/straight neutral. However, note the bottom graph (14 day prediction), which has been mainly negative and has averaged -0.7194. So, the 14 day prediction has had a negative bias of 0.7194 + 0.0081 or a -0.73 AO bias. So, I'm advising extra caution about GEFS based -AO predictions.
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Here's leads and lags of the NAO, Atlantic Ridge, and Scandinavian blocking pattern wrt each phase of the MJO from Cassou (2008).
https://www.nature.com/articles/nature07286

Notice the -NAO peaks about 2 weeks ish after a phase 6 MJO event.
nature07286-f1.2.jpg
MJO, NAO, AR, and SCAND Lead & Lags.png
EMON_phase_MANOM_51m_small.gif


Here's another piece from Shao, Song, & Li in 2016 that simplifies the arguments presented in the aforementioned study.
http://www.lasg.ac.cn/mjo-workshop/ppt/poster/Poster-sxl.pdf
Screen Shot 2018-02-06 at 12.29.59 PM.png

Here's a nice chart from ECMWF that shows the probability of a particular phase of the NAO based on where the MJO is located and the associated leads/lags. Almost 50% of the time we observe a negative NAO after a Pacific MJO (Phase 6-7) event.
Screen Shot 2018-02-06 at 12.26.23 PM.png

There's a multitude of studies on this topic that delve into the MJO-AO/NAO relationship, I'll just post a few here, strongly suggest reading these, they're well worth your time and not terribly technical
http://onlinelibrary.wiley.com/doi/10.1002/qj.2917/abstract

https://journals.ametsoc.org/doi/pdf/10.1175/JCLI-D-15-0502.1

https://journals.ametsoc.org/doi/pdf/10.1175/2008JCLI2515.1
 
Webberweather53 said:
Here's leads and lags of the NAO, Atlantic Ridge, and Scandinavian blocking pattern wrt each phase of the MJO from Cassou (2008).
https://www.nature.com/articles/nature07286

Notice the -NAO peaks about 2 weeks ish after a phase 6 MJO event.
View attachment 3840
View attachment 3838
View attachment 3843


Here's another piece from Shao, Song, & Li in 2016 that simplifies the arguments presented in the aforementioned study.
http://www.lasg.ac.cn/mjo-workshop/ppt/poster/Poster-sxl.pdf
View attachment 3839

Here's a nice chart from ECMWF that shows the probability of a particular phase of the NAO based on where the MJO is located and the associated leads/lags. Almost 50% of the time we observe a negative NAO after a Pacific MJO (Phase 6-7) event.
View attachment 3842

There's a multitude of studies on this topic that delve into the MJO-AO/NAO relationship, I'll just post a few here, strongly suggest reading these, they're well worth your time and not terribly technical
http://onlinelibrary.wiley.com/doi/10.1002/qj.2917/abstract

https://journals.ametsoc.org/doi/pdf/10.1175/JCLI-D-15-0502.1

https://journals.ametsoc.org/doi/pdf/10.1175/2008JCLI2515.1
Click to expand...

Thanks, Webb. This is still a lot to take in for someone who likes things kept relatively simple so as to be able to fully wrap my head around it all. One thing from that that immediately got my attention is the EMON (Euro monthly) MJO forecast of it going into phase 8 on 2/18 and then down into low end moderate to weak phases 1 and 2 2/22-3/9. I do like seeing that as phases 1 and 2 do lean cool on average in the SE.
 
Webberweather53 said:
Here's leads and lags of the NAO, Atlantic Ridge, and Scandinavian blocking pattern wrt each phase of the MJO from Cassou (2008).
https://www.nature.com/articles/nature07286

Notice the -NAO peaks about 2 weeks ish after a phase 6 MJO event.
View attachment 3840
View attachment 3838
View attachment 3843


Here's another piece from Shao, Song, & Li in 2016 that simplifies the arguments presented in the aforementioned study.
http://www.lasg.ac.cn/mjo-workshop/ppt/poster/Poster-sxl.pdf
View attachment 3839

Here's a nice chart from ECMWF that shows the probability of a particular phase of the NAO based on where the MJO is located and the associated leads/lags. Almost 50% of the time we observe a negative NAO after a Pacific MJO (Phase 6-7) event.
View attachment 3842

There's a multitude of studies on this topic that delve into the MJO-AO/NAO relationship, I'll just post a few here, strongly suggest reading these, they're well worth your time and not terribly technical
http://onlinelibrary.wiley.com/doi/10.1002/qj.2917/abstract

https://journals.ametsoc.org/doi/pdf/10.1175/JCLI-D-15-0502.1

https://journals.ametsoc.org/doi/pdf/10.1175/2008JCLI2515.1
Click to expand...

Webb,
So, are you predicting based on what you posted that ~two weeks after this past MJO phase 6 event (1/28-2/1) that there will be a -NAO? That would be around 2/11-15, which the GEFS still has as solidly +NAO and the GEFS over the last 4 months has on average had a -0.34 NAO bias at forecast day 14. The bias at day 10/7 has been -0.27/-0.15.
 
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GaWx said:
Webb,
So, are you predicting based on what you posted that ~two weeks after this past MJO phase 6 event (1/28-2/1) that there will be a -NAO? That would be around 2/11-15, which the GEFS still has as solidly +NAO and the GEFS over the last 4 months has on average had a -0.34 NAO bias at forecast day 14. The bias at day 10/7 has been -0.27/-0.15.
Click to expand...

It's really not as simple as "ok, the MJO is here so in exactly 2 weeks we can expect the NAO or AO to do X" or that "x model has had x bias for y period of time" it's dependent on the speed & amplitude of the MJO, what time of the year it's occurring and how this registers onto the inherent synoptic-planetary scale internal variability and background forcing, etc. For example, a faster moving MJO event may limit the amount of forcing and possibly the duration of the forcing it imparts onto the planetary-scale wave train, and it can constructively or destructively interfere with it such that the forcing response is entirely different in particular situations, even if the forcing is the same (i.e. the MJO is in the same spot with the same amplitude). I know you like to simplify things, but that's the issue with atmospheric science, it really isn't that simple, there are a smorgasbord of nuances I'm only beginning to scratch the surface with here that need due consideration. In any case, I'd postulate that we are likely to see the NAO turn out less positive during the 3rd-4th week of February perhaps extending into early March as well, a significant (< 1 sigma) negative stint is entirely and legitimately possible imo which lends credence to what both the EPS & GEFS are forecast but it's highly dependent on how much interference occurs w/ the background state, the speed and amplitude of the MJO, the evolution of the polar vortex split and how much coupling occurs between the stratosphere and troposphere, etc (all of these should sound familiar). In any case, this should be fun to watch, it's been a long time since I've seen an instance like this where literally everything is going for very strong MJO activity in general in the extended range. The MJO backswing in the Indian Ocean several weeks from now will be crucial in determining the amount of damping we see w/ our downwelling Kelvin Wave in the West Pacific, if there's limited activity here, it could allow the Kelvin wave to continue amplifying unhindered, if the easterly trades are temporarily restored, it may trigger a resurgence of easterly trade winds that could aid the NINA in hanging around a little bit longer. In any case, the combination of a record breaking +PMM in the late winter and extreme WP MJO event at this time of the year of comparable magnitude to ones that preceded our 2 most recent super El Ninos is a death sentence to this La Nina
 
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Taylor C said:
I love how the models are warmer now, and there’s no artic outbreak for us. :) The GFS never gets me to freezing or below over the next 14 days. Clap to the thread title being very wrong.
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Maybe so but the first part has had some freezing and the last week is very much in doubt as per Webb and others. Plus, the reference was to SERidge's February up in Indiana, not to the SE's Feb.
 
Taylor C said:
I love how the models are warmer now, and there’s no artic outbreak for us. :) The GFS never gets me to freezing or below over the next 14 days. Clap to the thread title being very wrong.
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Well the title of the thread was right for some areas. North GA and the Carolinas had some ice recently. Brent may have ice tonight and then again this weekend. And of course its snowy and cold here in Indiana.
 
SoutheastRidge said:
Well the title of the thread was right for some areas. North GA and the Carolinas had some ice recently. Brent may have ice tonight and then again this weekend. And of course its snowy and cold here in Indiana.
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You need a job
 
It’s okay that it is wrong. I agree at the end of January things were semi looking that way, but February doesn't look like it is going to be freezing, and ferocious anymore.
 
EmersonGA said:
Not all! I'm well within the metro but there was a sharp cutoff to my south.
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What I was discussing, since 2/25/15 came up, was about how after Atlanta proper started out with rain, afterward there was a nasty dry slot that set up in which if you were in Atlanta proper or ANYWHERE on the latitude of Atlanta in nearby towns and cities, it was forget it snow wise completely. It was 35 in Atlanta proper which while above freezing, is workable, but since a dry slot set up, instead of possibly seeing snow, it was just miserable drizzle to wrap it up there. Can't lie, I was laughing at it that night but again getting dry slotted is for the birds.

North Atlanta suburbs, especially Northwest did perfectly fine. It may have been a north of I-20 storm in Alabama but in Georgia, I'd call it more of a north of the I-85 corridor storm, especially once you got to Atlanta.
 
Funny how February looks now when the long range looked good at the end of January. Of course the best storm we had first showed up on the models only 5 days out.
 
Perspective ...
It was in later January when everything looked to rock this month. Now it is only what ... Oh yeah ... February 6th, and models look bad, so and the winter is written off? The models were wrong in late January, correct? What was that, 10 or 12 days ago? What is to say definitively the models are not also just as wrong now?
Just askin' ... ;)
Best,
Phil
 
The Arctic is now back up to a whopping 15C warmer than normal, which is the largest daily anomaly since December of 2016:

http://ocean.dmi.dk/arctic/meant80n.uk.php

To give you better perspective, today's Arctic temp. is normal for near April 1st! Holy torch!

Edit: KSAV had its coldest week in 41 years Jan 1-7, 2018, which was just after the Arctic was averaging ~8C warmer than normal..
 
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1300m said:
While a fair point, we now have the calendar working against us. If we get into a better pattern it is going to be 2/20 or later, leaving roughly 3 weeks of prime climo time left for even the upper South. I'm not writing off that 3 week period, but that's basically all we have left of true winter outside of a rather anomalous later March storm.
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Could not agree more; just trying my level best to help preserve someone else's sanity while still being realistic ... ;)
~~~~~~~~
The last thing I can be accused of is having a bias, warm or cold ... But it is worth tossing out thoughts, even when it looks like the handwriting might be on the wall ... so long as thse thoughts are tempered by realism ... :cool:
 
It wouldn't shock me if we see a Substantial Severe Weather setup mid month in the South as the pattern changes.
 
SoutheastRidge said:
Well the title of the thread was right for some areas. North GA and the Carolinas had some ice recently. Brent may have ice tonight and then again this weekend. And of course its snowy and cold here in Indiana.
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We’ve been pretty cold up here also with a few flurrie events this past week. Rest of this week looks cold until the weekend. Hopefully the gfs is wrong because it does show some very warm temps next week.
 
12z euro next Monday.

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Wishful thinking? Probably


Sent from my iPad using Tapatalk
 
image.png
The cold air is there. It just doesn't want to pay us a visit. Folks, get ready. February is about to be a real burner. Time to break out the sunscreen. I'm sorry
 
1300m said:
While a fair point, we now have the calendar working against us. If we get into a better pattern it is going to be 2/20 or later, leaving roughly 3 weeks of prime climo time left for even the upper South. I'm not writing off that 3 week period, but that's basically all we have left of true winter outside of a rather anomalous later March storm.
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Please consider this as a 2nd reply to your post.
A brief war story.
I represented a landowner whose property was severely polluted by a petroleum company. The State required a full remediation; the dig was begun on 2/26/04; the location was about 30 miles ENE of Gainesville. The engineers and others on hand to monitor were from Canada. They flew in, with "summer" clothes, expecting "Florida weather", as it had been quite warm, somewhat akin to now. The remediation dig took 3 days. On day 1 it rained. On day 2 it sleeted all day, and was so cold that the digital cameras the Canadians brought down to document actually froze. On day 3, it was bitter raw.
None of that weather was forecasted ...
So, strange things can happen ... even when least expected ...;)
Just not every day or year mind you ... :cool:
... and probably not this year ... o_O
 
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