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

[CG2]

Give me this stalled frontal boundary all day long.  Looks at the high over southern Iowa and how strong it is.

[Holston_River_Rambler]

A lot of energy in the SW and a big old HP, the drama, the drama of it all:

 

[CG2]

At 1053 hp in the Central Plains at 150 and a stalled frontal boundary here.  

[CG2]

Something has to run that boundary, right?

[Holston_River_Rambler]

4 minutes ago, CG2 said:

Something has to run that boundary, right?

I just hope it doesn't lift north as the vort kicks out. But it looks like the Pac jet is blasting at the Pac NW and that, along with the departing TPV as a 50/50, could help keep it from gaining latitude. I bet we end up with a massive Miller B, (this run) but we will see. 

[CG2]

I think the Euro is still just messing around in the southwest.  Nearly perfect gradient look.  All other modeling at 12z  has precip running that.

[Holston_River_Rambler]

There almost a wall of snow from Canada to the Rio Grande on one frame of this:

 

wow

[Holston_River_Rambler]

You can also see how far south the boundary has made it into the Gulf on that run. That would seem to encourage a low to form pretty far south. 

[Holston_River_Rambler]

Looks like icepocalypse (ok maybe an exaggeration) over middle and east TN, with snow west. Energy goes negative too early that run. But if it is playing games in the southwest, that could evolve better over time. 

 

[Holston_River_Rambler]

[Mrwolf1972]

Utter mess on euro on the 16th 

[CG2]

Welp...supplant overrunning with a kitchen sink system at 192....the bath tub, sink, porcelain throne, a couple of toothbrushes, towels, and maybe some light fixtures.  All of it.

[tnweathernut]

2 minutes ago, Holston_River_Rambler said:

Looks like icepocalypse (ok maybe an exaggeration) over middle and east TN, with snow west. Energy goes negative too early that run. But if it is playing games in the southwest, that could evolve better over time. 

 

Yeah, I was just mentioning to @Carvers Gap how I thought there's virtually no way what the 12z euro shows at 500 actually happens after 72-96.  i'd say the potential cold press in the near/mid term is legit and the chances for ice that come along with it.  Toward late next and weekend I have a big problem with how this model run of the euro plays out at 500.  Way too many intricate interactions happening to play out this way.  Guess we will see.

[John1122]

The edge of the ZR shield in the Euro has moved south about 40 miles on 3 consecutive runs. I doubt it's done moving yet. That's happened in almost every event since Christmas.

[CG2]

I will give this to the 12z Euro, the gradient pattern doesn't leave - even after that storm.  Seems like the 12z suite of models definitely liked some type of overrunning in the subforum area....timing  and number of events are the variable.  Fairly significant signal for winter.

[CG2]

11 minutes ago, John1122 said:

The edge of the ZR shield in the Euro has moved south about 40 miles on 3 consecutive runs. I doubt it's done moving yet. That's happened in almost every event since Christmas.

Agree.  Reminds me of November '18 or '19 where it just couldn't catch up.

[Mrwolf1972]

Anyone got ice totals on euro ?

[John1122]

Winter storm watches going up in Kentucky, I expect they may in West Tennessee and over to the Clarksville area as well. The RGEM/GGEM has ice storm warning criteria from the Plateau west in the d3 time frame.

[John1122]

6 minutes ago, Mrwolf1972 said:

Anyone got ice totals on euro ?

[John1122]

This is the 24 hour trend on the Euro for the ice coming in a couple of days, courtesy of Myfrotho.

[John1122]

This is a good illustration of the very consistently busted high temp forecasts in the area.

 

[Mrwolf1972]

13 minutes ago, John1122 said:

Thank you 

[TellicoWx]

32 minutes ago, John1122 said:

Two things (which some of us have already discussed) #1 temps are usually overdone on high side at mid/long range modeling, and #2 models tend to underperform on qpf vs reality. Taking those two things in account, with the setup across all 12z modeling...those maps may unfortunately be on the light side if everything holds together.

[Bigbald]

I work in wise, VA, so I am super interested in the little meso scale between rgem and Nam.  Rgem really gets messy in far swva there in the short term.

[Stovepipe]

MRX getting cute with the Canadian joke.

Quote

000
FXUS64 KMRX 082030
AFDMRX

AREA FORECAST DISCUSSION
National Weather Service Morristown TN
330 PM EST Mon Feb 8 2021

.SHORT TERM...(Tonight and Tuesday)...Sluggish return flow trying to
get started ahead of inverted trough to our northwest.  Low clouds
are expected to spread across the area late tonight in return flow
aloft--little bits of QPF are shown in some model output late
tonight in the deeper moisture, but this low level moisture is not
connected to anything aloft to get any ice crystal growth, etc., so
will keep QPF zero through Tuesday, along with mainly single digit
POPs in the grids. Could see some patchy drizzle in a few places,
but not much else.  Guidance temps look good with notably milder
night tonight, and warmer Tuesday.

GM

.LONG TERM...(Tuesday Night through Monday)...
Frontal boundary will focus precip Tuesday night and Wednesday
mostly to our north over KY before it finally surges south Wed
night, bringing precip in from the northwest such that the entire
forecast area should receive precip...mostly rain...on Thursday.
As post-frontal cold air continues to invade the area, the precip
will be trying to exit, but the back side of the precip area will
probably experience a transition to snow before ending by Friday.

Precip chances (mostly 30-40%) return Friday night and Saturday
according to the NBM, and the ECMWF has suggested the same, although
the 12Z GFS is notably more skimpy.

However, beyond Saturday, the models are struggling to resolve the
energy in this progressive pattern. For it is then that the GFS
really rushes a strong weather system in from the southwest for
Saturday night and Sunday morning with lots of precip falling upon
our cold airmass, which is a potentially messy solution indeed. The
NBM and ECMWF (and even the Canadians eh) are much more conservative
with lingering and mostly insubstantial precip. We and surrounding
offices are going with the NBM-led majority but will watch what
happens to the GFS solution with interest.

 

[John1122]

I'm honestly not sure where MRX sees the snow when all modeling suggests ice. They have low snow chances in my forecast several days in a row. Hope they are right.

[Mrwolf1972]

18z gfs takes the ice on the 14th to ohio but has a storm with snow in east tn 16th into 17th like cmc and euro. 210 snow forecast below.

[Stovepipe]

6 minutes ago, Mrwolf1972 said:

18z gfs takes the ice on the 14th to ohio but has a storm with snow in east tn 16th into 17th like cmc and euro. 210 snow forecast below.

 

A great low track for us and for once no marginal temps to deal with.  Sign me up.

[TellicoWx]

While the NAO can assist the TN valley (more the eastern side vs western side), the Pacific still/ and will always rule the roost. Until we can get the ridging off the west coast nudged closer to shore (GFS hints at that evolution toward day 7-8 beyond), I'm not that confident the cold will get shoved far enough east for the eastern valley..(different story for the western areas). Due to the shape of the state (horizontally oriented), it's what makes getting a statewide event so difficult. Place the ridge far enough offshore (west thrives), right against shore (east thrives/but systems can't get the moisture far enough back to help the west side. 

[TellicoWx]

Posted by Alan Gerard on Twitter..excellent example of how globals near surface resolution don't allow them to see shallow level cold that well.