February/March 2020 Winter's Last Chance Thread

[Holston_River_Rambler]

8 minutes ago, weathertree4u said:

Possible impact end February? 

Judah Cohen, despite all his hype and attempts to use twitter for a variety of ends, shared some research yesterday that is helpful:

The projected displacement puts us in cluster 2 and at least gets us close to cluster 4 which would be ideal. I'd like to see all this within like 3 days at this point, but all models are at least consistent showing that it will get displaced our way. That seems more reasonable than a split with how strong this SPV has been and probably the best we can hope for. 

No clue how quick it would respond for us, even if we get the best case scenario, but at least the cold air is on our side of the globe for once at high latitudes, so we could be getting a lot worse looks at long range right now. Even the cluster 2 and EPS over night look zonal and would get us out of this flood pattern. 

[weathertree4u]

Just now, Holston_River_Rambler said:

Judah Cohen, despite all his hype and attempts to use twitter for a variety of ends, shared some research yesterday that is helpful:

The projected displacement puts us in cluster 2 and at least gets us close to cluster 4 which would be ideal. I'd like to see all this within like 3 days at this point, but all models are at least consistent showing that it will get displaced our way. That seems more reasonable than a split with how strong this SPV has been and probably the best we can hope for. 

No clue how quick it would respond for us, even if we get the best case scenario, but at least the cold air is on our side of the globe for once at high latitudes, so we could be getting a lot worse looks at long range right now. Even the cluster 2 and EPS over night look zonal and would get us out of this flood pattern. 

So, what you are saying is the cluster continues 

[Holston_River_Rambler]

At second glance Euro actually looks close to cluster 4 at day 10, so I guess me might be closer than we think. But we gotta remember how bad this base state has been this year too. Doesn't mean it can't change, but whatever can go wrong at range this year, usually has. 

[Holston_River_Rambler]

1 minute ago, weathertree4u said:

So, what you are saying is the cluster continues 

Indeed. 

as always credit to @PowellVolz for bringing this, the greatest of all gifs, to my attention. Also, feel free to deny everything if I get in trouble for this, lol. 

[PowellVolz]

Indeed. 

as always credit to [mention=14393]PowellVolz[/mention] for bringing this, the greatest of all gifs, to my attention. Also, feel free to deny everything if I get in trouble for this, lol. 

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[Holston_River_Rambler]

3km NAM looks fun for the duration of its run:

Keep in mind, some of the snow early on is not the normal wrap around upslope, it is driven by an upper low and the strengthening surface low to the lee of the Apps. 

[Holston_River_Rambler]

This one almost meets the definition of a bomb cyclone according to the NAM and RGEM, goes from 993 to 969 in 20 hours. Should be a dynamic system. 

[Wurbus]

I'm not getting my hopes up here in the valley, I'll believe it when I see it. I do think the plateau and mountains will do well though.

[Holston_River_Rambler]

Probably a good bet to expect stuff to go wrong, given how things have been this year, sadly, not even sure I will do well. @Kentucky looks pretty good and as of now and I will say that just went outside and the temp has started to drop, rain has ended and the wind is howling in the trees. Big difference in only 30 minutes when I got back from my ramble out to the Obed. 

 

[Carvers Gap]

So did the 12z GFS just eliminate the ridge(edit) inside of 240 for the most part?  It has another snow threat inside of 150.

[Carvers Gap]

12z GFS is a major break from continuity very early in the run....

[Carvers Gap]

It has another threat around 240.  Not sure I believe that run, but that is a lot of cold(well inside of 240).

[weathertree4u]

1 minute ago, Carvers Gap said:

It has another threat around 240.  Not sure I believe that run, but that is a lot of cold(well inside of 240).

Lol, you are being punked 

[Carvers Gap]

2 minutes ago, weathertree4u said:

Lol, you are being punked 

Don't worry.  I am used to it.  LOL.

[Carvers Gap]

Let's see if the CMC follows what the GFS just did.  This trend began at 0z on both the GFS and CMC, but have been waiting to see if the operationals doubled down at 12z . The CMC was cold at 0z late in the run.  And we all know the rules...so I don't have to restate them.  We will watch the 12z suite and see if the Euro shows any hint of support.  Just a little surprised to see modeling flipping around well inside of d10.  It it isn't real, we just get a good laugh.  

[Carvers Gap]

The CMC basically just did the same thing.  Not going to get into the "is it real" stuff.  Good chance it won't be.  However, anyone care to venture a guess on why the sudden change?  Just talking model stuff and not forecasts....

[Carvers Gap]

The best I can tell is that there are hints of a PNA ridge and the EPO is in tighter.  This forces the trough out of the West and creates a more progressive pattern where there are troughs in the East.  Guessing something inputed(model data) has changed something on those two models.  I don't bite on (edit..lol)one off model runs, but I do take notice.   The 12z CMC and GFS are not that different at all.

[Carvers Gap]

Go to the 12z GFS and look at hour 342...that is a monster western ridge?  Probably going to roll eastward, but...LOL...that is crazy.

[Carvers Gap]

So far, the 12z ICON, GFS, and CMC are singing the same tune.  Looks like a cold front of some sort is being picked-up around the 14th.  Only thing I can possibly assume is that something has changed with the MJO.  It is definitely different on the ECMF which is making a bee line to 7 before fading off late.  Keep in mind, that model was in the COD prior or low amp.  If the high amplitude GEFS is in "half right" as the Euro has caved there...maybe modeling is seeing the MJO move out of 6 quicker?  That just doesn't account for the flip early in the run.  Maybe just be three models making a hiccup....If the MJO is not going to stay in warmer phases longer...the EPO might hold in place?

[Holston_River_Rambler]

UKMET kind to plateau at elevation and E KY at 12z:

[Holston_River_Rambler]

Start a thread for this one, or no? 

[Carvers Gap]

12z GEFS obviously won't flip like the GFS(basically two different models), but there are new features on that 12z GEFS run.   A stout PNA ridge  has formed post 300 w a trough plopped right over the Aleutians.  Like I said, not sure what has changed, but there is definitely something different so far.  I do not look for the Euro/EPS to change quickly if at all.  Like I said, it corners slowly.  If something is truly afoot, one would likely see it change over several runs in small increments.  

But overall, pretty shocking to see a model flip like the 12z GFS just did...basically wall-to-wall eastern troughs.  At this point, I can't completely toss it since it has support from other operationals and some support at the surface on the GEFS and at 500 after 300 hours.  Trust me, I would like to toss it...just not yet.  Right now, I consider this a one-off suite of runs...but will keep watching.  Would not be the first time modeling has flipped like this...usually it is from a great pattern to one that stinks.  So for now, it is an anomaly.

[PowellVolz]

Start a thread for this one, or no? 

I say go for it. I mean.... I’m not real concerned with it not snowing because we jinxed ourselves.


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[Carvers Gap]

Just now, PowellVolz said:

I say go for it. I mean.... I’m not real concerned with it not snowing because we jinxed ourselves.


.

LOL.  Exactly.  Why not?  Right.

[nrgjeff]

Good news for the Plateau, Mountains, and maybe Nashville. Both waves appear to be night and morning timing now. Gosh, when did snow forecasting get as diurnal as severe forecasting? Anyway seems like a dusting to half inch along and north of I-40, except that ends on the Plateau (inclusive of course).

Upper Plateau and into Kentucky looks like 1-2 inches, locally more Plateau. 

Bad news: Great Valley boundary layer is still a no-go. Even Nashville looks better than TYS and MRX. I have trouble taking out TRI, but the models are not friendly.

Tonight looks like cyclonic flow plus short-wave hybrid, decent moisture left over. Friday night and Saturday morning looks less juicy now. Southern Apps may get their turn though.

[Carvers Gap]

And the 12z Euro has the 132 storm seen on the GFS.  Again, like this weekend's third wave, just looking for placement.  BTW, the Euro has 2-3" of snow over northern sections of middle TN for the trough event that we have been following.  

[franklin NCwx]

1 hour ago, Carvers Gap said:

12z GEFS obviously won't flip like the GFS(basically two different models), but there are new features on that 12z GEFS run.   A stout PNA ridge  has formed post 300 w a trough plopped right over the Aleutians.  Like I said, not sure what has changed, but there is definitely something different so far.  I do not look for the Euro/EPS to change quickly if at all.  Like I said, it corners slowly.  If something is truly afoot, one would likely see it change over several runs in small increments.  

But overall, pretty shocking to see a model flip like the 12z GFS just did...basically wall-to-wall eastern troughs.  At this point, I can't completely toss it since it has support from other operationals and some support at the surface on the GEFS and at 500 after 300 hours.  Trust me, I would like to toss it...just not yet.  Right now, I consider this a one-off suite of runs...but will keep watching.  Would not be the first time modeling has flipped like this...usually it is from a great pattern to one that stinks.  So for now, it is an anomaly.

That's a big move towards a western ridge on the 12z gets. The 6a had hints of it earlier.  Hopefully this is correct. 

[Holston_River_Rambler]

Euro looks like it is trying to get it done. Nice AO vibes, but Euro does the old dump the energy in the W. At least there seems to be more often than not lower heights in the Aleutians and the ridging occasionally makes it to western Canada. 

[Holston_River_Rambler]

Seems like recently, the reality of the speed of the flow has been kicking energy out of the SW a little better than the Euro says

[Carvers Gap]

The correction(not idea of temporary or permanent) on the Euro at 132 is significant.  It actually leaves the cutoff in the Southwest.  It opens the door for the next potential winter event if true.  This cutoff has been a thorn on modeling for almost a couple of weeks.  It has yet to be sorted out.  I doubt the 12z GFS is likely not valid as it is too progressive, but I also have my doubts about the Euro as it has a really tendency to dig too much into the West.   The problem is there is very little middle ground.  Either the cut-off moves along and doesn't dig into the West OR the northern stream uses that cut-off to dig the trough into the West OR the northern stream leaves the cutoff and digs into the East.  I am not so sure that the Euro didn't just bend pretty heavily to the other operational models.  At 222, the Euro has a 1045 surface high in the Midwest.