February/March 2021 - Frigid or Flop? Pattern/Longterm Forecast Thread.

[Carvers Gap]

Just now, PowellVolz said:

So I’m assuming it’s much warmer later next week?


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Just posted the MSLP comparison anomaly above...

[Carvers Gap]

This is my opinion, I think the Euro is playing games again in the West.  It has a tendency to dig too much out there.  This solution was different from Wednesday onward - way different.  Just going to have to wait on its ensemble to see if this is a big shift or an outlier.  Tendency would be to toss it as of now...but will wait to see the EPS.

[Carvers Gap]

12z Euro is much different than the 12z suite and much different than its other runs.  It may be correct and it may not be.  I think it is a combination of an error(getting hung up in the West for the umpteenth time this winter only to have it not verify nearly as strong) and a legit MJO trend not to go into phase 8 but the COD.  It will be nearly 40-50 degrees warmer in some forum locations for later next week.  At this point, I am not buying that extreme of a shift, but there is some trend to keep the cold west of the Apps - that I buy...just not West of the Apps as in Oregon.

[Shocker0]

50 minutes ago, Wurbus said:

If the upcoming potential ice storm does happen, it reminds me a lot of the storm we had back in Feb 2015, at least IMBY. We had ice and snow, followed by very cold weather and it hung around for awhile. Now the one being modeled on the CMC is much worse. Also, I had an ice, wolverine claw form over several days next to my house back then.

 

We had about 2 inches of ice here in that one :/. It was actually our second ice storm of the week in Crossville and I thought the first one was bad until this one hit.

[Bigbald]

12z icon similiar to gfs etc with the artic boundary battlefront the Apps at around 165 hrs...  Euro is really on its own here

[Carvers Gap]

The 12z EPS provides some support for the operational.  However, it is not to the extreme extent that it flips the pattern. Still has the overrunning event later next week.  Something to keep an eye on for sure...big changes from the Euro should not be taken lightly.

[John1122]

The Euro has been doing the flip flop quite often this year beyond D5. It started in late November and has continued it throughout winter.

[Carvers Gap]

Regarding mid-late week overrunning event:

The 12z EPS pushes the front through E TN at 174 which is later than 0z which was at 114.   Everything is similar to 0z until the front hits west TN and then it CRAWLS across the state for nearly 60 hours.  So, that creates an extended time opportunity for overrunning.  The operational doesn't press the front through E TN until 222!  It stalls the front in Missouri.  So, there is some support to slow the front, but the actual operational is out of step with pretty much every model at this point....but I don't discount it.   The EPS still has the overrunning window while the operational halts the cold in the Plains.  

[Carvers Gap]

The 12z EPS actually looks very much like the CMC operational.  

[snowmaker]

To me the latest CMC  run came in closer in line with the GFS also overall. Kinda looked colder too me as well. I am right?

[Carvers Gap]

I am going to ride with @PowellVolz on this.  I think something is out of whack right now.  It is definitely not out of the ordinary for modeling to flip.  Happens more than we like.  That said, this flip flop stuff from one extreme to the other is odd within short time increments.  Might see one flip, and that is it...but not the multiple extremes which we have seen for several days.  Maybe it is just extreme cold which is in play.  Maybe it is just shoulder season stuff since we are leaving our normal, winter long wave pattern.  Maybe there is a computer or data problem. Something is off.  

[Coach B]

10 minutes ago, snowmaker said:

To me the latest CMC  run came in closer in line with the GFS also overall. Kinda looked colder too me as well. I am right?

I don't think the 12Z CMC was as cold as its previous run or as cold as the 12Z GFS. However, it did have WAY more frozen precip than its previous run across the forum area. 

[PowellVolz]

I am going to ride with [mention=14393]PowellVolz[/mention] on this.  I think something is out of whack right now.  It is definitely not out of the ordinary for modeling to flip.  Happens more than we like.  That said, this flip flop stuff from one extreme to the other is odd within short time increments.  Might see one flip, and that is it...but not the multiple extremes which we have seen for several days.  Maybe it is just extreme cold which is in play.  Maybe it is just shoulder season stuff since we are leaving our normal, winter long wave pattern.  Maybe there is a computer or data problem. Something is off.  

My only issue is both of the Euro’s freak outs are not that far apart. So it makes it even harder to trust it overall.


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[Holston_River_Rambler]

Back in MoCo now. Here are the EPS members snowfall through hr 180. That may give some hint as to where to sees the boundary.

 

[Carvers Gap]

1 minute ago, PowellVolz said:

 

My only issue is both of the Euro’s freak outs are not that far apart. So it makes it even harder to trust it overall.


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Definitely not just a Euro problem.  The UKMET, GFS, and CMC all seem to be jumping around in unison which makes me thing there is a data ingest(or lack thereof) problem.  The shift in unison away from the pattern a few days ago and then promptly back...makes me think we have a data issue.  Ensembles, as MRX notes, are probably the way to go right now.  They have been pretty steady.

[Carvers Gap]

2 minutes ago, Holston_River_Rambler said:

Back in MoCo now. Here are the EPS members snowfall through hr 180. That may give some hint as to where to sees the boundary.

 

Which looks like the CMC/GFS operational combo.  

[Holston_River_Rambler]

I mentioned the parallel Euro earlier. The new version of the Euro that is supposed to be operational later this year:

 

I'm sure it's not currently the OP for a reason, but I'll take that over cold rain or ice, any day...

[Carvers Gap]

5 minutes ago, PowellVolz said:

 

My only issue is both of the Euro’s freak outs are not that far apart. So it makes it even harder to trust it overall.


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But one place the Euro is really susceptible is with getting hung-up in the southwest...but that normally happens at d+5.

[PowellVolz]

I mentioned the parallel Euro earlier. The new version of the Euro that is supposed to be operational later this year:

 
I'm sure it's not currently the OP for a reason, but I'll take that over cold rain or ice, any day...

I’d bookmark that photo just for reference


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[Holston_River_Rambler]

We've noticed that the Euro has a tendency to overamp storms in the mid range, right? What if it is overamping a big cyclone in the N. Hemisphere and that just has huge implications because what we are dealing with is a major TPV piece and any small changes in it's location can have big consequences:

a 969 low S. of Greenland and a 959er in the Aleutians.

 

GFS is totally different with those major storms:

 

CMC looks more like the Euro, but still gets the cold eastward.:

 

The one feature that really stands out to me is the low and associated energy west of the W coast:

 

maybe that is exerting influence and pulling the bigger energy westward. To extend Carver's hurricane analogy, it's as if you have a cut off in the fall over TX or the Gulf, and it helps steer a hurricane more west? 

 

If that ends up incorrect though, it might be able to swing SE more. 

Yesterday's 12z Euro run had the feature much weaker:

[Daniel Boone]

Looks to me it's just pulling it's bias of holding energy back in the west and that energy pulling the trough back there. Hopefully, that's the case.

[Carvers Gap]

2 minutes ago, Daniel Boone said:

Looks to me it's just pulling it's bias of holding energy back in the west and that energy pulling the trough back there. Hopefully, that's the case.

Agree, just not used to seeing it do that inside of 120.  

[John1122]

Odds are 0z is wintery, then back a few more times. I remember noting in the Christmas storm thread or leading up to it that the Euro had to be right at some point because it showed every possible solution you can have in Tennessee in late December in the days leading into the event. It's flipped around significantly with this storm. Sadly the Para GFS is down at the most crucial time. It was on a hot streak. They probably discovered it was doing better than the Euro at  500 and tinkered with it to make it worse.

[PowellVolz]

Odds are 0z is wintery, then back a few more times. I remember noting in the Christmas storm thread or leading up to it that the Euro had to be right at some point because it showed every possible solution you can have in Tennessee in late December in the days leading into the event. It's flipped around significantly with this storm. Sadly the Para GFS is down at the most crucial time. It was on a hot streak. They probably discovered it was doing better than the Euro at  500 and tinkered with it to make it worse.

I think the euro was right around d7 I believe


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[Carvers Gap]

12z GEFS still shows the potential for overrunning next week.  Probably just need to lean on ensembles right now and not operationals....stuff is all over the place right now even inside of d3.

[AMZ8990]

9 hours ago, Carvers Gap said:

@AMZ8990, that right over your house?

Almost, one county over to the east of the High would be my house.  

[dwagner88]

8 hours ago, Shocker0 said:

We had about 2 inches of ice here in that one :/. It was actually our second ice storm of the week in Crossville and I thought the first one was bad until this one hit.

Wow. I'd forgotten how bad this was just north of here. That's a crazy picture. One of those rare times I was glad to miss out on an event. Stayed at 33 here. Then we thankfully got rocked by the miller A on the tail end to the tune of 8-9".

[John1122]

GFS still honking wide spread frozen events over the next week. Basically the entire forum will see some kind of frozen precip over the next 7-8 days and the cold will be stiff. At one point there's snow falling with Temps in the upper single digits and low 10s. Exactly where will not likely be determined until it's falling. Especially the freezing rain/sleet possibilities. But the cold is almost always further south and east than modeling indicates when they happen. 

[John1122]

Winter event for western areas starts in about 4 days or so per the Canadian. One wave moves through then another comes along. Massive West Tennessee ice storm.  

[John1122]

Long duration and slow buildup is the worst case scenario.