February/March 2020 Winter's Last Chance Thread

[Holston_River_Rambler]

Happy hour agrees:

[Holston_River_Rambler]

@Carvers Gap re: the NAO discussion on the last page, if you go to Isotherm's blog/ page 50, he actually breaksdown his method.

09 - 10, he called for a +NAO:

 

source (def. worth a read and something I will bookmark and revisit):

https://www.lightinthestorm.com/page/50 

[PowellVolz]

I’ll take my chances with everything south of us and I wouldn’t feel good about it if I was in the sweet spot right now.


.

[jaxjagman]

1 hour ago, Holston_River_Rambler said:

@Carvers Gap re: the NAO discussion on the last page, if you go to Isotherm's blog/ page 50, he actually breaksdown his method.

09 - 10, he called for a +NAO:

 

source (def. worth a read and something I will bookmark and revisit):

https://www.lightinthestorm.com/page/50 

That's probably not exactly true to an extent because this has been one of the strongest +AO ever recorced since 1990

Edit:Nevermind,i didnt know this was last year

[Holston_River_Rambler]

11 minutes ago, jaxjagman said:

That's probably not exactly true to an extent because this has been one of the strongest +AO ever recorced since 1990

Sure and I agree. I think he would too. He was calling for more high lat. blocking this feb and that has yet to materialize in a meaningful way. 

[Holston_River_Rambler]

21 minutes ago, jaxjagman said:

Edit:Nevermind,i didnt know this was last year

No worries I see what you mean now

[Mr. Kevin]

I'm not the smartest guy with weather, but every system has trended north this winter, but now with energy coming out of the sw and it can't produce a winter storm with a decent hp up north. Blows my mind. If the hp was further nw, it would trend nw for sure. 

[TellicoWx]

For those who may be looking for a positive trend to the GFS, take a look at the soundings over each run for the past 24-36 hrs..it has dwindled away the dry layer each run (good sign if you are looking for overrunning). Known bias during the 3 - 7 day window, GFS normally runs too cold (pushes the cold too far south, too quickly)...Euro during that same window has a tendency to hold the energy too far back (Carvers excellent point over the last day or so). These bias tend to typically be what leads to the NW trend with systems as the events get closer in time, even though they are the results of different corrections (GFS corrects its push, while Euro ejects quicker)....until they start coming into agreement within 48-72 hrs. Each system/scenario is different, but hopefully this is what is occurring now (bias/correction phase). Change in soundings on GFS over the past 24 hrs over the southern valley...

[jaxjagman]

Have to wait and see where the MJO goes towards the end of the month.There is some signs today the WWB won't be as strong as it has been showing BUT still looks like the next several days east of the IDL will be impacted with all kind of waves the next few days.

 

Prognostic Discussion for Week 3-4 Temperature and Experimental Precipitation Outlooks
NWS Climate Prediction Center College Park MD
300PM EST Fri Feb 14 2020

Week 3-4 Forecast Discussion Valid Sat Feb 29 2020-Fri Mar 13 2020

The incipient global tropical convective pattern is complex, with areas of enhanced convection observed both over the eastern Indian Ocean and near the Date Line. The latest RMM-based MJO index, which serves as a predictor for the Week 3-4 multiple linear regression (MLR) statistical forecast, has responded to the latter convective signal, with a West Pacific (Phase-6) projection. Despite this signal, however, the future evolution of the MJO signal is uncertain, so lagged teleconnections to the extratropics are difficult to discern at this time. A pronounced westerly wind burst is ongoing near the Date Line, and this feature may generate an oceanic Kelvin wave that allows warm water to move eastward over the next month or so. While this activity is unlikely to play a substantial role in the global circulation during the Week 3-4 period, it may play a role in the broader Boreal Spring time frame.

Dynamical model 500mb height anomaly forecasts for Week 3-4 do not show a substantial change from the persistent positive AO structure observed since the beginning of the calendar year. The CFS, ECMWF, and JMA all show pronounced ridging over the North Pacific, particularly south of the Aleutians, with below-average heights over the Arctic and extending over Greenland and to some extent over Canada. This pattern suggests that the CONUS would be vulnerable to cold air intrusions, but the positive NAO feature over the North Atlantic would make such outbreaks transient in the East. All three dynamical model systems depict a weakness in the height field over the Southwest, which may provide a conduit for Pacific flow into the U.S., particularly across California. While the CFS shows near- to below-normal heights across most of the CONUS, the ECMWF and JMA maintain a Southeast ridge, which may impact where the focus for enhanced precipitation lies.

The Week 3-4 temperature outlook is based primarily on a blend of the CFS, ECMWF, and JMA solutions, with the statistical contribution fairly weak due to competing (and uncertain) signals from the MJO and long term trends. In a pattern shift, above-normal temperatures are forecast across Alaska as ridging builds to the south. Below-normal temperatures are favored across much of the northern tier of the CONUS, with a southward extension to the Central Plains due to the potential for cold air intrusions from Canada. Dynamical models also favor increased chances for below-normal temperatures across New England. Below-normal temperatures are also slightly favored along the West Coast, which may be due to SST influences. With high uncertainty and a transient pattern favored during the period, equal chances for above- and below-normal temperatures are maintained across much of the rest of the CONUS, while above-normal heights favor above-normal temperatures for the Florida Peninsula.

The area of highest confidence in the precipitation outlook is Alaska, where dynamical models strongly favor enhanced precipitation across the western half of the State and along the North Slope. Below-median precipitation is forecast for the Alaska Panhandle and Pacific Northwest, while Pacific moisture may result in enhanced precipitation for central and southern California and parts of the Great Basin. Further east, the possibility for cold continental airmass intrusions into the central U.S. favor below-median precipitation for the Plains, Great Lakes, and New England. Across the Southeast, a mean frontal boundary is anticipated to set up, with dynamical models favoring the Tennessee Valley (JMA), Appalachians (ECMWF), or the Southeast Coastal Plain (CFS) for enhanced moisture. Based on these various solutions, a fairly broad area of enhanced probabilities for above-median precipitation were included on this outlook for the Southeastern U.S.

SST anomalies remain above-normal in the vicinity of Hawaii, although the magnitude of the anomalies have been gradually decreasing. Dynamical model forecasts, including the Subseasonal Experiment (Sub-X) suite, are mixed, so equal chances for above- and below-normal temperatures are maintained across Hawaii. Dynamical models generally favor enhanced precipitation.
 

[jaxjagman]

The pattern looks really similar to the pattern we seen in mid Jan,but its more hostile this round east of the IDL,this is where after the MJO bombed out into the Maritime in Jan

[jaxjagman]

I dont agree with some of the models as well,there's been some hints of the long range models showing a strong system in the long range,there should be a ridge in the east with a potential building +PNA,in all honest  this could be more a severe threat in the long range IMO

[jaxjagman]

That is a beast of a storm in the North Atlantic to fly recon to see how strong the the ocean winds are

https://www.tropicaltidbits.com/recon/

This in turn should really cool down the NA Tripole.if this were into a transition Nina this would be signs of some potential severe outbreaks into the Plains into the Valley in the warm season

[jaxjagman]

The strong +AO in Feb of 1990 it had a neutral ONI like this year kinda speaking.This brought on some sig flooding down south of us and into the SE subforum,then into summer the flooding went into the OV.iF the MJO which we dont know right now gets back strong into 4 once again the chances would seemingly be we will have a chance to see once again see some sig flooding,this also has a chance to be an active severe season 

[Holston_River_Rambler]

OP Euro didn't necessarily get any worse overnight for the 21 - 23 system.

Still south, but even a little bit more north from yesterday. I'll wait for the NAM to nail the coffin.

It also suggests that there could be a Gulf low late in the run. Could be one to watch as the EPS is pushing another western/TX trough just after hour 240. And it seems to me if one fizzles out, sometimes a second one can surprise, JMO. 

At least either way we dry out for a while.  

[Holston_River_Rambler]

Further out in time, the Euro Control and EPS, suggest what looks to me like an odd/ blocky pattern, :

GEFS and GEPS have something similar:

 

I can't tell if that is a good look, or if it would just give us a bunch of cold/ rainy cutoffs?

 

 

[weathertree4u]

30 minutes ago, Holston_River_Rambler said:

Further out in time, the Euro Control and EPS, suggest what looks to me like an odd/ blocky pattern, :

GEFS and GEPS have something similar:

 

I can't tell if that is a good look, or if it would just give us a bunch of cold/ rainy cutoffs?

 

 

I would put my money on a bunch of cold/rainy cutoffs. As I said previously, persistence has won the modeling battle this year, we have been here before, always looks good in the long range but when we get to the long range it turns out to be the same as the current time frame and I think others have eluded to this, even though most of us want at least one good system, we recognize the struggle that modeling has gone through this year. I mean, again, as previously mentioned by others, the current cold shot for mid month, the one we have now, originally started out as a pattern flip, then down to a week or so, then in reality, it is about 48 hours of cold. So, while I like the look and though this post does not necessarily indicate it, I am hopeful we can pull out one good system but I recognize we are now working against climatology every day we move closer to meteorological Spring. 

[Carvers Gap]

Modeling has indeed been pretty bad this winter, but the EPS has done quite well during February with the 500 pattern.  Temp bias towards cold is noted.  The EPS hit the Feb 5-10th pattern from almost 15 days out.  It also had a very warm period from the 10-20th with a few hiccups to cold, but eventually retained the original warm-up.  The GEFS is always cold after d10...and is about worthless right now because of it at that range.  I am basically using the GEFS to see if it agrees with the EPS.  Both models have a cold bias, but the EPS seems to be locating features at 500 reasonably well at range with understandable hiccups.  The trick at LR is just to realize that the d10-15  is just not that accurate and have to take into account bias.    The EPS missed the Feb 14th cold front, but hinted at the Feb 19th front from LR.  JB had a great discussion from a few days ago.  He mentioned that the MJO would likely have been a strong 4-6 phase for most of winter winter had it not been for some counterbalancing of western IO convection at times which created a false COD signal.  His opinion is that the phase 6 region, which was sitting right on top of the very warm ENSO 4 region, was basically what drove the NA pattern.  As noted above, that SST4 region was a true El Nino and may have very well driven Nino conditions that verified as much stronger than a weak Nino.  That area fooled modeling and humans repeatedly.  Some good evidence(consistent with El Nino conditions) of this is that the northern Rockies, excluding one small area in western Wyoming and eastern Idaho, are BN for precip for January which is nearly opposite of last winter when the PV landed in MT and never left and they were hammered with snowstorm after snowstorm.  Here is a fantastic blog that I read for that area.  The person who writes this used to work in Norman, OK, in severe stuff.  He has an advanced degree in meteorology.  Also, if you need some great snow pics...his area is actually in the area that did get AN precip.  This is his January write-up, but would encourage you all to read some of the other stuff.  Just another world at 6,000' in the northern Rockies.  

http://blog.starvalleyweather.com/2020/01/31/january-weather-summary-snow/  

[Carvers Gap]

As for the LR, the EPS has had one variation or another of cold beginning around Feb 20th.  Seems like it has finally settled on Feb 20-24th as the next cold shot and is potentially hinting at another around the 28th.  At 0z, the EPS 10day mean for the 20-30th(generally speaking of the entire forum area) remains normal to slightly BN for temps w precip BN with the exception of Memphis.  Again, as has been noted on multiple occasions...there appears to be a cold front of varying strength rolling through about every 5-6 days.  

Is the pattern after the 20th a pattern change?  Not sure.  There is a strong cold shot, sharp warm-up, and another cold from modeled in that 10day period beginning on the 20th.  Changing wavelengths could cause a prolonged pattern relaxation like they did in November.   I do think the SER is going to fight as long as phase 6 is sitting on top of AN SSTs.  The trough on the 0z EPS is at d12 right now for that second shot of cold.  It is tough to tell if it is a pattern change because the model only runs through d15.  I think a prolonged pattern relaxation of 10-14 days is certainly within the realm of possibility - meaning a colder pattern in the East.  It very well could be that we are going to enter a time frame where there is more balance.  

As for the system next week...right now it is suppressed.  The Euro trended slightly north with its precip shield at 0z.  The 0z CMC has more interaction between the northern and southern stream which allows precip to spread into southern areas of the sub forum.   I will not be surprised to see this come north over time.  Still 5-6 days before that event even gets here.  That is 20 more runs of the GFS and 10 more runs of the Euro operational before verification.   My guess is that there are a few more turns(maybe not huge ones...but trending still very possible one way or another) at this range.

[Carvers Gap]

4 hours ago, Holston_River_Rambler said:

Further out in time, the Euro Control and EPS, suggest what looks to me like an odd/ blocky pattern, :

GEFS and GEPS have something similar:

 

I can't tell if that is a good look, or if it would just give us a bunch of cold/ rainy cutoffs?

 

 

Could be two camps or it could be a -EPO ridge being undercut w blocking over the top.  Verbatim, that is a good look, but it is way out there so that likely changes some.  Looks like two more windows before the month is up - d6ish and d12ish.  I can't decide if I like the digging into the Southwest around the 27th.  It may be another error.  That said, if it digs that much that could be a big storm coming east right behind a cutter.  Kind of has that look.  When one looks at the gif above, storms coming in around LA have a tendency to exit at the same latitude.  So, we might get a cutter but the next storm might exit at the same latitude as Los Angeles.  Seems a "cutter followed by a coastal" type of look as the trough pushes eastward.  I can say this...much more interesting than December and January where we had virtually nothing to track or even discuss other than d10+ maps.  Right now we at least have something to watch at d5-6 and have had two recent snow threads..  LOL.

[Holston_River_Rambler]

Up in Kingsport right now so no pics, but the UKMET looked a tick better with a wave that rides right after the mid week front drops through, but still suppressed after that 

[Carvers Gap]

It is worth noting that ensembles beginning around Dec 20 are cold for about 6 of the next 10 days after that...sometimes quite cold.  Cold bias is possibly and even likely in play.  I think the Feb(edit) 20th cold shot is likely.  The immense surge of cold modeled around the 27/28th is probably feeling some bias.  Still, the 500 pattern on ensembles(operationals for the first one) portrays two strong cold shots.  Again, how long is that second shot going to hold?  No idea, and not sure ensembles give us many clues either.  I was not overly impressed by the MJO this morning.  PSU noted in the the MA thread that phase 8 is not really where we want to be at this time of year, and I concur.  He noted that we need it in 1, 2, and 3, and I concur with that as well.  So, seeing the MJO bend away from phase 8 is likely a plus.  Looks to me like a null signal(probably a false null) with some potential to trend away from warmer phases on the ECMF w the ECMM less enthusiastic.  It is a bit surprising to see the LR models so cold in the LR...colder than the usual bias.  If they miss this time, verification will not be pretty as they are quite cold.   If they verify, it will feel like winter during both of those windows.  

[WinterWonderland]

Carver, did you mean to say February?

[Carvers Gap]

35 minutes ago, WinterWonderland said:

Carver, did you mean to say February?

Yeah, thanks.  Fixed it.  LOL.  Would have been a heckuva call ten months out...

[Holston_River_Rambler]

Tropical convection looking a lot like it did about a month ago. Winding up and aiming southeast. 

Today (sorry no gif, Himawari was acting weird, flickering in and out):

Last month:

 

That added +AAM and resulted in: (loop from Jan 24 - 28)

Sorry for the speed, more meant to show the Hudson's Bay block. 

 

Some similarities on today's EPS, at least through hr 270:

 

 

[Holston_River_Rambler]

Also interesting to see how the Control progresses the flow after the giant cutter the OP is starting to show (and the EPS is dead set on). Looks like it opens the gates of the arctic:

[jaxjagman]

28 minutes ago, Holston_River_Rambler said:

Tropical convection looking a lot like it did about a month ago. Winding up and aiming southeast. 

Today (sorry no gif, Himawari was acting weird, flickering in and out):

Last month:

 

That added +AAM and resulted in: (loop from Jan 24 - 28)

Sorry for the speed, more meant to show the Hudson's Bay block. 

 

Some similarities on today's EPS, at least through hr 270:

 

 

This is where your MJO signal is at right now around the dateline.Noticed the GEFS is showing the EPO flipping to - into the last week of Feb,this should happen as these KW'S pass east of Hawaii basically

[Holston_River_Rambler]

I'll see if I can find some pics, but apparently the EPS and control at 18z looked a lot better for the post frontal deal later this week. 

[Holston_River_Rambler]

Hopefully the southernwx folks won't kill me for stealing these pics, but I don't have access on weathermodels for 18z EPS to more than basic maps.  EDIT: sorry just realized that this is the control only. The mean does look better though. 

[Holston_River_Rambler]

This is the best I have from weathermodels, MSLP:

 18z:

 

VS

 

6z

 

[Carvers Gap]

18z EPS mean also allows the 6hour qpf shield to move north as well.  Pretty big move.  Let's see if the 0z supports it.