January 2023 Mid-Long Range Disco

[cbmclean]

15 minutes ago, CAPE said:

That is a multiple year monthly composite mean at h5 for December. There would have to be some amount of ridging in the Western US (during Dec) for at least parts of some of those years. When presented as a multi-year composite, the height anomalies there are less prominent and get 'washed out'.

True, but there is the strong eastern trough signal as well as a weaker but less robust trough off the west coast.  I'm just surprised to not see a similar consistent signal in the western conus.  The patterns are complex and many-faceted, and sometimes defy easy characterization

[CAPE]

6 minutes ago, cbmclean said:

True, but there is the strong eastern trough signal as well as a weaker but less robust trough off the west coast.  I'm just surprised to not see a similar consistent signal in the western conus.  The patterns are complex and many-faceted, and sometimes defy easy characterization

It might be interesting/useful for you to create an h5 anomaly plot for each of those Decembers individually.

[cbmclean]

15 minutes ago, CAPE said:

It might be interesting/useful for you to create an h5 anomaly plot for each of those Decembers individually.

I'm at the inlaws for Xmas so hopefully I'll have some time to play this evening

[CAPE]

@WxUSAF

 

[WxUSAF]

I’ll take it!

[SnowenOutThere]

Just got NAM’D, I think? I mean it’s more than what the other models show

[Terpeast]

Not saying we'll get anything out of it, but isn't that a clipper that was deemed extinct since 2015?

[Maestrobjwa]

18z GFS tryin' to give us a little love with the clipper

[yoda]

18z GFS has a quick shot of light snow at 06z Tuesday as well

[Weather Will]

Hmmm….4 days out the GFS gave me 4 inches today and I got 4 flakes.  Now I am getting .6 inch 4 days out so I guess I will get half a flake on Tuesday.  The Doug K. Curse continues….

[CAPE]

@leesburg 04

maybe..

[Scraff]

35 minutes ago, CAPE said:

@leesburg 04

maybe..

Break out the shorts, flip flops and margarita mix? 

[yoda]

40 minutes ago, CAPE said:

@leesburg 04

maybe..

Thunderstorms?

[brooklynwx99]

we are going to torch through the first week of January

however, there is increasing confidence that the Pacific jet will retract after this timeframe. this will push the ULL over AK back to the Aleutians, likely allowing for a strong -EPO/+PNA to develop, similar to what we're seeing now. you can actually see the poleward wave breaking at 200mb. pretty good signal

blocking isn't showing its hand on the ensembles yet, but blocking in Jan is quite likely given how blocky this month was. the persistent negative anomalies in the Atlantic also point towards its development

so, we're going to have a reprieve, but it should be only that. winter may return in earnest around the 10th or so... Arctic flow would make Canada cold very quickly, and we're in peak climo at that point

[Terpeast]

14 minutes ago, brooklynwx99 said:

we are going to torch through the first week of January

however, there is increasing confidence that the Pacific jet will retract after this timeframe. this will push the ULL over AK back to the Aleutians, likely allowing for a strong -EPO/+PNA to develop, similar to what we're seeing now. you can actually see the poleward wave breaking at 200mb. pretty good signal

blocking isn't showing its hand on the ensembles yet, but blocking in Jan is quite likely given how blocky this month was. the persistent negative anomalies in the Atlantic also point towards its development

so, we're going to have a reprieve, but it should be only that. winter may return in earnest around the 10th or so... Arctic flow would make Canada cold very quickly, and we're in peak climo at that point

And is there a sign of a STJ about to develop (negative h5 anomalies east of hawaii)?

[cbmclean]

9 hours ago, CAPE said:

It might be interesting/useful for you to create an h5 anomaly plot for each of those Decembers individually.

Well start going backwards in time.

Dec 2010.  Eastern trough is centered rather south compared to the composite and a good bit off shore.  No mean western ridge.  

[cbmclean]

Dec 2009

Quite different.  No mean E trough at all.  Instead negative anomalies centered over the great plains.

[cbmclean]

December 2000 will always have a fond place in my memory.  HGad just went off to college where I really blossomed after a difficult high school experience.  And the late fall/early winter was memorably chilly.

 

[cbmclean]

December 1995.  Crazy east trough although mostly off-shore.  Definitely no WAR.  Western ridge is also displaced east.

Actually from the North American view this doesn't look like a massive -AO.  Maybe the other side of the artic was high?

[cbmclean]

And that's all I could at this link:

https://psl.noaa.gov/cgi-bin/data/narr/plotmonth.pl.  

It says that plots are only available for data going back to January 1979.  From the previous post it looked like someone has data goign back to at least 1950.  Anyoen have any idea where I can get that?

[cbmclean]

And finally, unrelated to my recent posts, I remember some discussion about whether or not the GEFS had been updated to run on the "new" GFS dynamic core.  I stumbled across this article while looking for more reanalysis data.  Apparently GEFS went to FV3 way back in Sept 2020.

https://journals.ametsoc.org/view/journals/wefo/37/6/WAF-D-21-0112.1.xml

The Global Ensemble Forecast System (GEFS) is upgraded to version 12, in which the legacy Global Spectral Model (GSM) is replaced by a model with a new dynamical core—the Finite Volume Cubed-Sphere Dynamical Core (FV3). Extensive tests were performed to determine the optimal model and ensemble configuration. The new GEFS has cubed-sphere grids with a horizontal resolution of about 25 km and an increased ensemble size from 20 to 30. It extends the forecast length from 16 to 35 days to support subseasonal forecasts. The stochastic total tendency perturbation (STTP) scheme is replaced by two model uncertainty schemes: the stochastically perturbed physics tendencies (SPPT) scheme and stochastic kinetic energy backscatter (SKEB) scheme. Forecast verification is performed on a period of more than two years of retrospective runs. The results show that the upgraded GEFS outperforms the operational-at-the-time version by all measures included in the GEFS verification package. The new system has a better ensemble error–spread relationship, significantly improved skills in large-scale environment forecasts, precipitation probability forecasts over CONUS, tropical cyclone track and intensity forecasts, and significantly reduced 2-m temperature biases over North America. GEFSv12 was implemented on 23 September 2020.

[psuhoffman]

2 hours ago, cbmclean said:

And that's all I could at this link:

https://psl.noaa.gov/cgi-bin/data/narr/plotmonth.pl.  

It says that plots are only available for data going back to January 1979.  From the previous post it looked like someone has data goign back to at least 1950.  Anyoen have any idea where I can get that?

https://psl.noaa.gov/cgi-bin/data/composites/printpage.pl

 

[Ruin]

8 hours ago, CAPE said:

@leesburg 04

maybe..

My argument to this is that 6-8 days before this artic cold they forecasted highs in the mid 40s to upper 40s from va md de pa. So I wouldnt put to much stock in what this says atm. with that said it most likely will happen just to screw us over lol. but its hard to predict any thing with these models a few days out let alone a week plus 

[CAPE]

9 hours ago, cbmclean said:

Well start going backwards in time.

Dec 2010.  Eastern trough is centered rather south compared to the composite and a good bit off shore.  No mean western ridge.  

Another view, slightly different plot. This is the 500 mb mean, minus the anomaly. You can see the NH longwave pattern. Note the Aleutian ridge and downstream trough (typical Nina), and downstream from that there is a western US ridge(somewhat flat), then the eastern trough and NAO ridge. On these data plots when you select "anomaly", if the h5 heights in a given area are normal, or very slightly anomalously high or low, there is no indication(coloration).

 

[CAPE]

The ens means in the LR and the extended products indicate the progression to a more favorable pattern will be focused on the Pacific with a +PNA/-EPO look emerging towards the 10th. That's a pretty good way to get some cold back to our nearby source region quickly. It looks like the AO will be around neutral, and the NAO slightly positive to neutral, at least initially. Perhaps later in January and into Feb there will be another -NAO period.

[WxUSAF]

20 minutes ago, CAPE said:

The ens means in the LR and the extended products indicate the progression to a more favorable pattern will be focused on the Pacific with a +PNA/-EPO look emerging towards the 10th. That's a pretty good way to get some cold back to our nearby source region quickly. It looks like the AO will be around neutral, and the NAO slightly positive to neutral, at least initially. Perhaps later in January and into Feb there will be another -NAO period.

Yeah, the same longer range ensembles suggest the Scandinavian ridge also redevelops, which could/should move toward the NAO space later in January.

[Terpeast]

At the moment, it looks like we go well AN between 12/28 and 1/9 then trend to near normal temps by 1/10. For now at least. 

[DarkSharkWX]

This certainly isn't a horrible look

[Terpeast]

14 minutes ago, DarkSharkWX said:

This certainly isn't a horrible look

Yeah, it’s good to see that there’s an end to the temporary warmth. We can snow on this look in January. 

[Weather Will]

Even while we torch during NYs cold air lurks in Canada, so we don’t have to wait for the whole Northern Hemisphere to cool down again…WB 12Z GFS