February/March 2020 Winter's Last Chance Thread

[Carvers Gap]

18z EPS mean also allows the 6hour qpf shield to move north as well.  Pretty big move.  Let's see if the 0z supports it.

[Carvers Gap]

18z EPS mean is on the left.  

[Chattownsnow]

43 minutes ago, Carvers Gap said:

18z EPS mean is on the left.  

Looks a good bit warmer as well. I guess that’s what you have to sacrifice a little in this situation. 

[Holston_River_Rambler]

0z Euro OP looks north for especially the second wave, even some snow into VA, though that could be from a N. steam shortwave trying to hook up with the energy ejecting out of TX:

 

[Carvers Gap]

1 hour ago, Holston_River_Rambler said:

0z Euro OP looks north for especially the second wave, even some snow into VA, though that could be from a N. steam shortwave trying to hook up with the energy ejecting out of TX:

 

6z GFS came north as well.  The 6z GEFS mean has bumped up along the border of AL and TN to around 1.5" of snow.  Let's see if it keeps trending.  

[Carvers Gap]

9 hours ago, Chattownsnow said:

Looks a good bit warmer as well. I guess that’s what you have to sacrifice a little in this situation. 

I think the question right now is whether we can get an overrunning event without pushing the cold out of the way.  Have to think it is possible, but is it likely?  Not sure.  Certainly recent trends are brining precip back northward to where it was originally modeled.  One more jog north and we might be tracking something.  Remains to be seen if that happens.  I think we see maybe 1-2 more jogs before it locks in, and then one last jog within 48 hours.  Also, very possible that modeling sees a colder air mass and presses it southward.  Pretty much everything is on the table with this.  LOL.  I suspect it keeps coming north, but will be interesting to watch at 12z and again at 0z tonight.

[Holston_River_Rambler]

the NAM at range looks like it wants to bring the whole shebang out of TX wit ha 1044 parent high nosing down:

 

 

 

[Holston_River_Rambler]

On the one hand I can buy into that, since the flow seems to have been more progressive than modeled this winter, but on the other hand, it is the NAM, builder of hopes and crusher of dreams

[Holston_River_Rambler]

GEFs and GFS like the idea of the second piece possibly coming out of TX:

 

UKMET says nope and suppression, though it is further north with the first piece of energy:

 

[Holston_River_Rambler]

UKMET does something odd with the energy, it pushed it ENE and washes it out, where the NAM and GFS kick more out.

Euro at 0z was a compromise between the two camps, we'll see what it says in about an hour. 

[Holston_River_Rambler]

Hvward, a met over in the SE mountains and foothills thread, brought up the NAVGEM scoring a coup DEC 2017. As I understand it, NAVGEM is generally the most progressive model and even it gets more precip north than the UKMET:

 

[Holston_River_Rambler]

Looks like the Euro is going to come in about the same as 0z, or maybe a little north, depending on the frame you look at. To my eyes anyway, just not a huge difference. 

But this seems to me to be sort of a hair trigger set up. To get precip you have to have two things, moisture and forcing. 

We have moisture at 500 and 700 mbs:

 

But a shortwave cuts off that flow as it swings through:

Now look how differently the NAM handles that piece:

The big HP looks like a done deal, we want to root for more return flow and it wouldn't take much given that the flow is basically W to E ahead of it on all models. Maybe there is reason to be hopeful as these shortwaves can sometimes amp up last minute....or at least suppression = more dry out time.

Hopefully we can eek out a few EPS hits. 

 

[Holston_River_Rambler]

So on second thought, I kinda think the piece of energy over the Pacific right now is a key here:

Euro swings it in underneath the N stream shortwave and squishes it while the NAM:

swings it out much more intact. 

Not saying the NAM will be right here, just that it is a touchy set up. 

[Holston_River_Rambler]

In fact here it is as of now:

 

Wish I had included CA for size, it is small but fiesty. 

[Holston_River_Rambler]

1/3 of EPS members are north enough to make it interesting at this range:

[Holston_River_Rambler]

It would be kind of a consummation for this winter if we got the look at hour 84, only to fizzle out and suppress as it moves east. 

[John1122]

I think the HP is being over modeled. The models and especially the GFS roll these big 1045-1050 highs down all the time and they verify at 1035 when they actually arrive.  

[Carvers Gap]

49 minutes ago, John1122 said:

I think the HP is being over modeled. The models and especially the GFS roll these big 1045-1050 highs down all the time and they verify at 1035 when they actually arrive.  

I agree.  Think that system is coming north due to that?  That is my thinking.  

 

[tnweathernut]

9 times out of 10 these setups will produce precip much further north than being modeled 3-4 days out...

that said, 500mb is a hot mess on most modeling, including the 12z Euro OP (i.e. we likely find the 1 out of 10).

[Holston_River_Rambler]

18z Euro looking better with the moisture in southern plains:

 

 

 

Looks like a little more SW flow, but its so close. What a weird set up in regards to its details. Lots of lil vorts in the southern stream too. The flow is almost precisely W --> E any variation to either NW or SW could produce very different results. 

 

[jaxjagman]

29 minutes ago, Holston_River_Rambler said:

18z Euro looking better with the moisture in southern plains:

 

 

 

Looks like a little more SW flow, but its so close. What a weird set up in regards to its details. Lots of lil vorts in the southern stream too. The flow is almost precisely W --> E any variation to either NW or SW could produce very different results. 

 

700MB are quite juicy,it's when you get to the 850mb it's quite dry

[jaxjagman]

Even with  what the Euro shows a 1047MBHP during this time into IOWA you'd expect some height falls but the raging jet just won't let it happen

[jaxjagman]

Long range models shows a trough going through East Asia today and another few days later.long range models don't show much right now with the first system which should reach the Valley around the 24th but show the 2nd system as more dominant,not sure that's going to be right but this is what long range is showing

[jaxjagman]

My thinking if i'm right this 2nd system what the Euro is showing is coming in to fast towards the NW

[John1122]

Big jump north on the Euro for the system Thursday.  Precip field moved from South of Atlanta at 12z to SW Virgina at 00z. A light stripe of snow falls across a lot of the state early Thursday that run. Will see if this is a trend toward even more moisture for us or not. The HP in Iowa and moisture in Texas is a classic for us normally. 

[John1122]

The NAM at 81-84 seems pretty decent for parts of the forum area as well. Keep in mind it's the NAM at 84. 

[Carvers Gap]

6z GFS trended north as well, but not quite to Euro levels.  As John noted, good look on the Euro...just very light.  Wonder if we can get the precip shield to expand without the cold being pushed out in response?  

[Holston_River_Rambler]

Euro also looks like it has some convection parallel to the Gulf Coast.  If that happened it could cut off the moisture to an extent. How long has it been since we've even had a chance to worry about Gulf convection cutting off moisture though, lol. 

[Holston_River_Rambler]

Our little shortwave west of CA still looks stout this AM and a nice moisture feed from the STJ in the Pac:

I feel like it might be a little more potent when all is said and done. 

[nrgjeff]

Just got back from skiing Snowshoe, WV. Talk about lucky/blessed in an otherwise awful winter. Snowed up there Friday and conditions gradually improved with each night of snow-making. Alas, this is my home thread back at 500 FT.

Gut likes Thursday along-north of I-40, plus the Plateau and Mountains. Wait, the GFS/NAM don’t have precip? A risk with such cold dry air. However that solid HP anchors any cold in place; so, it’s of course and overall big plus. ECMWF usually has QPF to/north of I-40; so, I think it looks good (NWP verbatim).

System originates in Texas and slides to our south, my favorite track. Yes basic WAA precip. Should not cut with northern stream pushing (billiard ball meteorology) if the surface high ain’t enough. 700 mb temps look close to ideal. Trouble is boundary layer. Anybody shocked there?

I think I said that before Chattanooga got 4 inches of boundary layer problems.