February/March 2020 Winter's Last Chance Thread

[Carvers Gap]

12z GFS with a storm around 10...The Feb 5-10 time frame still looks like maybe our best chance this winter so far.  It is a brief window, but a lot of things are in place that would support an EC storm.  No idea if the operational is correct, but it is just an example of what "could" happen.  

[Carvers Gap]

12z Model Mayhem continues:

GFS OP:  Won't bite on the eastern ridge.  Slides another trough in late.  It does have a cold bias late in its run, so that might be playing into it.  And I wonder if that is not what the ensemble is seeing Feb 10-20?  It has a SER but it might just be a brief ridge replaced by a trough, wash/rinse/repeat....

CMC OP:  New update, right?  Bout to find out if it is improved.  Dumps trough West and then crawls it eastward though the Euro had a run that was similar a few days back.  Wonder if the CMC now has a bias in the Southwest?   That has been an outlier solution so far as even its own ensemble doesn't support that.  Now, not sure if the ensemble is actually running off the same update.  Oddly, the GFS does the same thing with its second trough during d10-15.  

I have said this over and over again.  Don't like what you see, wait a couple of runs and it will likely be there.  

[Carvers Gap]

The 12z GFS has a very strong EPO ridge during this run.  The CMC isn't far off from that either.  The CMC is just slower but would likely get the same result a couple of days later.  We will see if this trends...both models have a better looking Pacific after Feb 5.

[Carvers Gap]

12z GEFS @ Pivotal Wx is done.  Trough ducks west around the 9th or 10th, and then like the Weeklies, centers back towards East right at the end of the run.  No idea if true, but that is a good trend if it were to continue.   Good thing is that there is precedent for that.

[Carvers Gap]

One final note here before the Euro rolls, the EMON/EMOM is super similar to the Weeklies last night regarding the MJO.  If you break  the next three days into 1/3s:  The first third is null.  Second third is 4/5 and little of 6.  Last third is null.  That fits really well with a cold shot in early Feb, a warm-up, and then the trough pushes back East as the MJO stalls.  All of that is at really low amplitude.  The GEFS wants to head towards 4 and bend back to 3.  This just tells me what we know from forecasts.  The MJO is going to have 2/3 firing along with 6 at times.  Going to be a battle and is likely why we see models waffling after Feb 10th.   One can see when looking at the equatorial are in the IO, MC, and western Pac the MJO firing in the sequence that the EMON has.   So again, looks like when the MJO goes into null gives us a clued as to when windows will be there for winter storms.  

[Holston_River_Rambler]

4 hours ago, Carvers Gap said:

PV update?  Forecasts and trends?

Euro back down a bit overnight, but GFS still saw it getting attacked as of 0z:

[Holston_River_Rambler]

12z GFS almost got it done:

[Carvers Gap]

Just now, Holston_River_Rambler said:

12z GFS almost got it done:

I just looked.  Yeah, the 12z basically split it.  It is even more noticeable at 30 and 50mbs.  That is a big development if true.

[Carvers Gap]

@Holston_River_RamblerI think the EPS/Euro handle the MJO regions really well.  But as we have noted, the GFS/GEFS probably handles the strat a bit better.  Not sure what to think at this point.  That will likely have impacts at high latitudes that modeling isn't seeing yet.  Looks like that has been on there for several runs.

[weathertree4u]

21 minutes ago, Carvers Gap said:

@Holston_River_RamblerI think the EPS/Euro handle the MJO regions really well.  But as we have noted, the GFS/GEFS probably handles the strat a bit better.  Not sure what to think at this point.  That will likely have impacts at high latitudes that modeling isn't seeing yet.  Looks like that has been on there for several runs.

Could that translate to cold here?

[Holston_River_Rambler]

It could, or it might not, we've seen both. 

Euro was brewing up some weird storm at the end and although it runs the low right in the eastern valley, there was still quite a bit of energy carving out a trough into the gulf

[Holston_River_Rambler]

 

 

[Carvers Gap]

The Euro digs the initial trough into TX this run.  It is sort of a compromise between the CMC and GFS.  It is worth noting that the big cold has slowed by about 36 hours due to the trough digging.  The cool thing about the trough digging is that it allows for the storm that Holston posted above.  I don't see anything at this point that makes me think the trough won't come East. The big EPO ridge should kick it out.  Just about timing right now.  But we don't want to see things getting pushed back and held at d8-9.  Need to see it moving forward.

Quick EPS update as in a bit of a hurry this afternoon:  The EPS does not slow the front down. (Edit:  Surface front slows down by about 18-24 hours...sorry, was in a hurry...500 has only slowed down by about 12) I am actually trying to decide if the trough digging is a bad thing.  That actually might allow the trough to have more staying power.  The EPS does sort of split the difference between the core of the cold on the 12z Euro and the 0z EPS.  Instead of the core of BN heights over the GL, it is heading down the Plains into the SE.  Model Mayhem...I keep saying it, but it is true.  Still looks like a decent window for a storm.

[Carvers Gap]

Also, looks like the 12z Euro OP splits the SPV as well.  I will let Holston unpack that.

[Carvers Gap]

The interesting development on the 12z EPS is that the trough is a bit slower to lift out and the storm track would be optimum around 228.  Of note, the ridge in the eastern Pacific is closer to the coast and stronger at 288.

[Carvers Gap]

At 288, more ridging into Alaska is evident.  Core of the cold is over the Plains.  Looks very much like a microcosm of November.  

[Holston_River_Rambler]

4 minutes ago, Carvers Gap said:

Also, looks like the 12z Euro OP splits the SPV as well.  I will let Holston unpack that.

I'll be honest, I didn't see much of a split, but you may have access to other levels than me, I only have 50 and 10 mb:

that is the 50 mb, and the 10 mb looks more consolidated. 

[Holston_River_Rambler]

EPS:

[Carvers Gap]

That run of the 12z EPS will work.  The cold is centered in the Plains and not the Rockies.  The cold would push on that boundary.  IF true,  that taps the GOM with that look late.  See how the boundary drags into the Gulf?  Fairly strong improvement IMHO and the ridge is closer to the West coast.  The SER has really been pushed toward the EC.  

[Carvers Gap]

@Holston_River_Ramblerlooks to me like that trough is going to lift out of the West fairly quickly.  Have seen that trend on modeling.  That is a textbook easterly QBO/solar min look.  I actually am a fan of the PV being over the HB an pivoting down cold - and I may have that backwards but that is what sticks in my mind.  

[Holston_River_Rambler]

Kinda matches the Euro and CFS weeklies too. 

[Holston_River_Rambler]

Maybe everything is finally lined up to give us more confidence, lol.

Or maybe we's about to get the old magic carpet ride:

 

[Carvers Gap]

1 hour ago, Holston_River_Rambler said:

I'll be honest, I didn't see much of a split, but you may have access to other levels than me, I only have 50 and 10 mb:

that is the 50 mb, and the 10 mb looks more consolidated. 

In my book that is a split given where it began at hour 0.  But I am comfortable with different terminology.  So, instead of split I will use an Eastman term:  process upset.  Used in a sentence it would work something like this....The SPV at 50mb is experiencing a major process upset.

[Holston_River_Rambler]

I'm down with that. Definitely not as healthy as it has looked most of this winter. 

[tnweathernut]

34 minutes ago, Carvers Gap said:

In my book that is a split given where it began at hour 0.  But I am comfortable with different terminology.  So, instead of split I will use an Eastman term:  process upset.  Used in a sentence it would work something like this....The SPV at 50mb is experiencing a major process upset.

Banter post.........   Looks like a fire breathing monster with ice cold eyes and green hair blowing a torch fest down on the lower 48.  

On topic, I will remain optimistic with what I am seeing.  In order for this to work though, we are going to need to see modeling correct colder at 2M.  This is something I can't remember happening in the winter months (D-F) in over 2 years.  I am in, until I'm out.  

[Carvers Gap]

Couple of images to explain my thinking regarding the EPS.  0z is on the right.  12z is on the left.  The first image(figure 1) is hour 198 which is February 5 @ 18z.  Notice the core of the colder air is further west vs being over Quebec.  Notice that the cold north of Alaska is stronger.  That stronger area of BN heights near Alaska likely weakens the downstream trough.  Notice how at 0z they(the two areas of BN heights) are similar.  JB likes to point out that there is only so much energy to go around.  Again, I don't do 2m temps on the EPS as they are often very biased towards warm.  I look at 850s.  That said, the 2m temps later in the run are impressive.  So, the trough at 500 is later by roughly 12-18 hours now that I have had time to dig into it.  You can compare the two images.   Instead of the cold digging with the feature in Quebec, it digs into the Plains and pushes eastward.  Almost all modeling is bouncing back-and-forth between placing the lowest heights in the northern Plains or Quebec.  You can see the difference.

Figure 1

Figure 2 shows what I consider to be fairly important improvements.  Notice the stronger heights at 330 are centered over Minnesota instead of Montana and Quebec.  That might mean the EPS is just splitting the difference between the two cold pools OR it actually now sees the cold in the Plains.  Either way, the result on this run is the positive axis of the trough being moved quite a bit further East.  With the area of lowest heights centered in the northern Plains, the cold air presses further into the SE and nearly eliminates the influence of the SER in our forum area, even bringing BN heights into west TN, Arkansas, far western KY, and Missouri.  That also means the storm track would theoretically slide eastward and run from Houston through TN to Massachusetts verbatim. In reality that front probably presses further east at the surface due to the cold being centered so close in the Plains relatively speaking.  That is a cold pattern.  Also note the ridging In Alaska along with the ridging building into the coastal areas of Pacific NA.  Another difference is the lack of Atlantic ridging.  That may very well have allowed the trough to be displaced eastward.  But the biggest takeaway from LR(and really LR at that) is that the EPS takes a big bite out of the SER and centers the cold further East.  

Figure 2

Lastly, I thought I would compare the Weeklies to actually EPS stuff now that it is in range.  This is the 7day 500 anomaly for February 4-11.   Figure 3 is from the Euro Weeklies derived on January 20th.  Figure 4 is the same time frame from the 12z EPS today which is a run eight days later.  While not perfect, the cold and trough axis in the lower 48 is nearly the same place.  Just showing that the Weeklies are doing fairly well right now in week 3.  Also note that the actual trough is being modeled deeper on today's run.

Figure 3

Figure 4

[Holston_River_Rambler]

CFS weekly for that period from 12z today looks pretty similar:

 

[Holston_River_Rambler]

Saw some other folks posting the EPS members and sure enough, at least for now, they are downright enthusiastic, for the period above, especially considering how far out that is

If you look really close, there's even one Chattanooga special in there, lol 

[Carvers Gap]

2 minutes ago, Holston_River_Rambler said:

CFS weekly for that period from 12z today looks pretty similar:

 

The thing I am seeing today is a bigger presence by the EPO ridge and a deeper trough somewhere east of the Rockies after Feb 5th.  I really have run with the premise that the trough does not hold.  But if that trough were to old like the EPS is showing, that would allow for really cold air to enter into the US.  Give me that pattern on the EPS and 2m temps take care of themselves.  No idea if that type of extreme look would verify.  If I remember correctly, the CFS and EURO had similar MJO trajectories this morning - for once.  I like that look, but do I trust the CFSv2?  LOL.  Anyway, at this latitude there are about 100 ways to achieve worse pattern.  Right now, I am just pointing out with modeling how things could lead to a decent window.  

[Carvers Gap]

16 minutes ago, tnweathernut said:

Banter post.........   Looks like a fire breathing monster with ice cold eyes and green hair blowing a torch fest down on the lower 48.  

On topic, I will remain optimistic with what I am seeing.  In order for this to work though, we are going to need to see modeling correct colder at 2M.  This is something I can't remember happening in the winter months (D-F) in over 2 years.  I am in, until I'm out.  

It has been a fight all winter.  I am looking for some cold pattern persistence!  LOL.