February/March 2020 Winter's Last Chance Thread

[Carvers Gap]

The 12z EPS has sped up(by about 20 hours) the eastern trough just after d10 w the first effects of the trough impacting western forum areas around 270.  As we suspected, the trough will try to lift out and another trough will attempt to reform in the West almost simultaneously.   Looks super similar to what will happen on the 14th and what occurred on the 7th.  This one rolls through on the 22nd - again almost every 7-8 days a big trough rolls through or front.  The trough on the 22nd is deeper w the AK vortex lifting out right at the end of the run...which is a good thing I think.  Lifts out and ridging from the EPO likely replaces it.  The EPS does look like a model flirting with phase 8 of the MJO at least just based on its look in NA.   I seriously doubt modeling has the pattern nailed down right now.  The Feb 14 cold front was basically missed in the LR by the EPS/Euro.  Cold air supply is notably weak for the Feb 22 trough.  Interestingly, the GFS does show some signs at 10mb late in the run of another SPV disruption, though lower levels are stout.  That does coincide with a strong WAR which precedes the eastern trough on the 22nd.  That WAR has preceded disruptions this winter and has precede strat splits in the past.  

[Holston_River_Rambler]

Sometimes I like to look at the EPS normalized anomalies, since they usually look better, lol:

Looks like it may at least be trying to push some of the cold out of AK later in the run:

[Holston_River_Rambler]

Sorry, was ninja'd by Carvers as I was contemplating looking at the CFS on pivatol, lol

[Carvers Gap]

The GFS does also have a notably strong SSW even at 10mb around the end of its run.  Unlikely that really helps our winter chances.  However, the SPV and TPV have been coupled this winter and a top->down split might cause blocking quite quickly.  If that is true, should start seeing some strong blocking signals showing up late in model runs during the next few days.

[Carvers Gap]

.  LOL.  Strat going to get bumped around on the GFS late in the run.  Temps really warm at 10mb.  I suspect this is the real deal.  Should make early baseball season super warm - not really.

1 minute ago, Holston_River_Rambler said:

Sorry, was ninja'd by Carvers as I was contemplating looking at the CFS on pivatol, lol

 

[Holston_River_Rambler]

Here is what @Carvers Gap was talking about for those interested, strat. temps at 10 and 50 mb. Highest anomalies are at 10 mb. 

That's a good warming, and I think the warmest it's shown all season,  but the wind field is still pretty consolidated:

[Carvers Gap]

We do a lot of strat talk in this thread.  Thought this was pretty interesting regarding the stratosphere and its importance in forecasting and modeling of wx:

https://usys.ethz.ch/en/news-events/news/archive/2020/01/forecasters-should-look-higher-up-to-predict-weather-weeks-ahead.html

[Holston_River_Rambler]

Looks like some healthy convection in 6/7 and maybe even some 8:

[weathertree4u]

Still like the time period around the 20th; I think we have some chances going forward and it may be like last week where the system really only comes into focus 48 - 72 hours before the event. 

[Holston_River_Rambler]

EPS overnight got a little more robust with its trough that rolls through late month

Maybe even some hint of a ridge trying to push into AK

Control has that:

[Holston_River_Rambler]

Euro kinda has the same system the 6z GFS has  (and has had off an on), but is holding energy back in the SW.

0z Euro

6z GFS

 

0z Euro

6z GFS

 

[weathertree4u]

2 minutes ago, Holston_River_Rambler said:

Euro kinda has the same system the 6z GFS has  (and has had off an on), but is holding energy back in the SW.

0z Euro

6z GFS

 

0z Euro

6z GFS

 

I would suspect that once we get past the system today modeling will come into better agreement, hopefully. 

[PowellVolz]

That’s a big step forward that the GFS brought that storm back and the Euro shows signs of it. Walk this in to d5 and anything is possible


.

[Carvers Gap]

Thought this was worth a share from Jax over in the ENSO thread.  JB actually shared this today...Jax shared this on Monday.  It is a great piece of information regarding the MJO.  

On 2/10/2020 at 4:27 PM, jaxjagman said:

Update prepared by the Climate Prediction Center Climate Prediction Center / NCEP 10 February 2020

 

• A pair of slow-moving envelopes of enhanced convection exist in the global tropics. The first is presently over the Western Indian Ocean, while the second is over the Maritime Continent. • Model guidance disagrees on which of these will come to dominate, with the GEFS emphasizing the latter center of action, while the ECMWF splits the difference and maintains both features. • Given this complicated perspective, extratropical circulation responses to the MJO are difficult to anticipate at this time. • A noteworthy possibility exists for anomalous low-level westerly winds east of New Guinea associated with the easternmost envelope of enhanced convection to potentially trigger a downwelling oceanic Kelvin wave. This would help to reinforce the volume of warm water available below the surface in the Pacific and possibly fuel an El Niño event.

 

[jaxjagman]

It's going into 8 for sure by the looks,question would be what does it do after?Should be be a CCKW crossing around the IDL the next couple days along with a ERW,by the looks.This should in turn upwell the warm subsurface SST'S along the IDL and east of it,plus you have a WWB which is already underway along the IDL.

[jaxjagman]

Global Tropics Hazards and Benefits Outlook Discussion

Last Updated: 02.11.20 Valid: 02.12.20 - 02.25.20

Investigating the current global tropical circulation reveals a complex perspective that may have lasting implications. Of interest are two eastward-propagating convective envelopes with the first currently over the eastern Indian Ocean and the second near the Date Line. In evaluating 200-hPa velocity potential fields, the latter region can be traced back in time through at least late 2019 with several periods of robust projections onto the RMM index during that interval. The former envelope may be shorter-lived, as it has to deal with the relatively hostile environmental conditions in the wake of the leading envelope to its east. Nevertheless, models differ on their handling of these two centers of action, and how dominant the easternmost feature will be, with the GEFS focusing on the eastern feature while the ECMWF allows the Indian Ocean convective center to linger and slowly drift eastward. Unanimous among the models though, is the forecast of a robust westerly wind burst during the second half of February that is likely to trigger a downwelling oceanic Kelvin wave that reinforces anomalous warm water volume near the Date Line. This bears monitoring for any longer-term implications and any potential El Nino event over the coming months. During the past seven days two tropical cyclones (TC) developed. The first was Tropical Cyclone Damien off the Kimberley Coast of Australia on the 6th, with the system tracking south-southwest before dissipating on the 10th. The second system was TC Uesi which formed in the Coral Sea on the 9th of February. Uesi has slowly tracked southward and is forecast to approach the east coast of Australia late this week before turning toward New Zealand. Areas being monitored for TC potential during the next two weeks include within the South Pacific convergence zone just south of American Samoa (high confidence during Week-1), the Mozambique channel (moderate confidence during Week-1, with development also possible in very early Week-2), or the central portion of the South Indian Ocean (low confidence during Week-1, with no TC shape forecast and instead a moderate confidence of above-normal rains area). The precipitation outlooks during the next two weeks take on somewhat of a character that features a West Pacific MJO (Phase 6 during Week-1, Phase 7 during Week-2) with increased uncertainty over the Indian Ocean with the second eastward moving envelope of enhanced convection and what role it may play amidst what would be conditions that are typically hostile to convective development. Highest confidence for enhanced rains are east of New Guinea with some extension into the South Pacific during both weeks. Confidence is high for anomalous dryness from the Timor Sea through Coral Sea during Week-1, which is replaced by a wetter pattern during Week-2. High confidence also exists for above-normal precipitation for portions of the west coast of South America, tied to sea surface temperature anomalies of 1-2 degrees above-normal combined with onshore flow oriented perpendicular to the Andes. Anomalous ridging over the Northeast Pacific leads to high confidence for continued below-normal precipitation across parts of the western U.S. throughout the outlook, while a tropical moisture feed across Mexico and the Gulf of Mexico into the Lower Mississippi, Tennessee, and Ohio Valleys results in high confidence for above-normal rains during Week-1. Remaining precipitation forecasts are in line with either forecast TC tracks or a consensus of dynamical model guidance between the ECMWF and CFS ensembles.

[Holston_River_Rambler]

Perhaps this is the long awaited November pattern return. 

[Math/Met]

I’ll move this to the main discussion based on Carvers suggestion. Just wanted to say that the wind event potential has trended a little stronger in my opinion. I thought the MRX discussion was very good regarding this potential.The NAM has slightly shifted the 850mb wind to more of a southerly direction, and that could be just enough to increase the mountain wave enhancement.  You don’t really need a southeasterly flow at 850mb because the cross barrier flow is determined at lower levels based on statistical analysis.  We often have a southerly or even slightly SW flow over the valley during a mountain wave event. This current event is right on the threshold, so it could go either way in terms of significant MW enhancement. Everything else is favorable. Regardless of MW enhancement, the LLJ is strong enough to potentially cause some tree problems in the mountain and foothills due to saturated ground conditions. 

[nrgjeff]

Oh yeah that pesky inversion will add to the mountain wave event, increasing the efficiency of the LLJ crashing down the north slopes. 

Weekend of the 22nd is starting to look interesting on the Globals for the Plateau and Mountains. Could be for anyone along-north of I-40. Not much to add at this point. Now that Chatty had it's good snow, I'm really rooting for y'all up there!

Oh hello 12Z Euro! It won't be that cold, but the attempt is good for winter lovers. Maybe a storm system instead.

[Carvers Gap]

The 12z Euro operational run today is a great example of how that run looks when it doesn't make the potential error of digging too far into the Southwest.  Thankfully, most modeling now seems to be free from this likely error.  What we now see now is periodic troughs digging eastward with fairy strong cold fronts.   The actually frequency of those fronts  has increased.  That is not a warm run of the Euro operational with cold pinwheeling in.  That actually looks like winter in terms of BN temps.  Same goes for the GFS which is pretty much constant winter anyway - broken clock analogy applies.  The last 7 days of the Euro operational are actually normal in terms of temps.  Minor miracle considering where we were during this time frame  a few days ago - if I remember correctly.  I might even call that a break in continuity...so let's see if if is a hiccup or a trend.  The 12z GFS and CMC are again basically singing the same song.

 

[Holston_River_Rambler]

EPS definitely has some support for the 21 - 23 time frame 

[Carvers Gap]

Very good trends on modeling since yesterday.  

[Holston_River_Rambler]

9 minutes ago, Carvers Gap said:

Very good trends on modeling since yesterday.  

EPS this PM definitely looks different, no normalized anomalies need for me today, lol:

[Carvers Gap]

2 hours ago, Holston_River_Rambler said:

EPS this PM definitely looks different, no normalized anomalies need for me today, lol:

The EPS is actually more aggressive than the GEFS right now...maybe because it stays out of phase 6/7 of the MJO and is in the COD(false null) longer.  But really, the general trend in modeling is towards a colder look and it has sped up some.  Easily could be a mirage, but first cold shot is next 48 hours.  Pattern looks like this past November vs Phase 6.  I am hesitant to be too excited but this has not been a terrible month from a tracking standpoint.  We have two event threads.  Get a couple of more threads by the end of the month and Feb has done its job....just no way to make up for Dec/Jan being torch city.  That said, starting to see that HB block show back up again. Also, if the EPS is correct, I bet that trough near the end of its run kicks right out with that set-up.  Really hard not to like where modeling is heading...Yeah, it might be late, but some of those looks at 500 are pretty nice.  Once this modeling worked-out the problems with those infinite loops of the Southwest trough...pattern had more cold in it.  

[Holston_River_Rambler]

18z GEFS looks like a really nice evolution again:

several good hits on the GEFS for the 21 - 23rd, even though the OP was a bit held back in the SW and suppressed. 

 

[Mr. Kevin]

We are running out of time regardless. Its already the middle of February. Its been  cold despite no -ao, nao, or epo here in my area. Just hope we have a realistic  chance at a winter storm. I just want 1-2 inches snow and I be happy lol.

[Carvers Gap]

6 minutes ago, Mr. Kevin said:

We are running out of time regardless. Its already the middle of February. Its been  cold despite no -ao, nao, or epo here in my area. Just hope we have a realistic  chance at a winter storm. I just want 1-2 inches snow and I be happy lol.

I hear that.  The HB block might be the ticket.  Just need to get some cold into that pattern.  The second half of January had some great tracks, but no cold.  

[Holston_River_Rambler]

Overnight Euro was interesting for the 21 - 23:

still a ways off to be talking about NW trends, but not a bad look overnight considering the consistency of the system on models. 

select cities from 0z EPS

Won't post all the overnight EPS surface plots like I did a few weeks ago, since that storm dissolved after that, but looking in the 7 - 10 day range, really nice looks on almost all members. Most of the misses are suppressed and not north/ rain. 

 

6z GEFS has a warmer solution for about 50% of its members

and the 6z GFS is suppressed/ holds energy back too long. 

One theme though is that a nice high is showing up, 1045 (GFS) - 1048 (EURO)

 

[Holston_River_Rambler]

CMC not bad either, for general look:

[Holston_River_Rambler]

A little hesitant to post one EPS member, but 28 does a good job illustrating what a NW jump on the OP could do for even Chatt: