February 2023 Medium/Long Range Pattern Discussion Thread.....Torch or Tundra???

[matt9697]

3 hours ago, Matthew70 said:

I will take a HARD PASS on any ice!  The extreme cold temps already damaged many of the evergreens & shrubs.  Sheesh last thing we all need is trees to be damaged also. 

The latest Canadian is showing a west tn event hardly anything middle tn

[Carvers Gap]

Let's see where we are this evening at 0z.  If west TN is still looking at wintry precip being modeled, probably time to create a thread for them.  All three deterministic models have very different placements for the anomalously cold air mass, and even with 100 hours to go until the first wave of frozen precip, solutions vary significantly. The 6z GFS is without some of its cold source again.  Looks to me like the CMC and GFS are a hair warmer.

[Carvers Gap]

Morning discussion out of Memphis:

A split upper level pattern will prevail during the early to
middle part of next week. The southern branch of the upper jet
will extend from the southern plains through the Midsouth and Ohio
River Valley. Concurrently, the northern branch of the upper jet
will extend from the southwest Canada to the Ohio River Valley,
where it will consolidate with the southern branch. At the
surface, a 1036mb Arctic high will drop into the Central Plains
Monday night, with the leading edge of this Arctic air enters the
Midsouth. Precipitation chances will increase through the day
Tuesday, as southern branch wave lifts into the lower Mississippi
River Valley. Thermal profile from GFS and ECMWF sounding depict a
mixture of freezing rain and sleet possible north of I-40 Tuesday
afternoon and Tuesday night.

Forecast confidence begins to wane a bit by Wednesday, due to
increased model spread. Discounting the much colder Canadian model
outlier, it appears that the Arctic airmass will modify Wednesday
afternoon, under low amplitude ridging aloft. This may result in
a transition to rain over northern portions of the Midsouth, but
this may be short-lived. Temps will likely fall below freezing
north of I-40 Wednesday night, as more precipitation arrives,
associated with an ejecting southern branch shortwave. Confidence
in precipitation type is lower with this second wintry event due
to model differences in the Arctic airmass position and strength
over the Great Plains.

[Carvers Gap]

As a follow-up to the Euro Weeklies last night, I am beginning to think that is an outlier run as generally all global ensembles have a decent warm-up mid-month.  Now, it is likely going to get cold again after that, but a warm-up now appears likely.  The real question will be the permanence of that eastern ridge.  Does it roll through or set up shop?  The Weeklies say it is temporary, but IDK.  We will see what the MJO says.   One positive note, the STJ appears to remain quite active.  That alone could give us some thread-the-needle chances(even during a warm pattern) just due to the frequency of precip and shortening wavelengths.  Very Nino looking pattern IMHO.

[Holston_River_Rambler]

One thing about the strat. is that I don't see any signs of it strengthening again yet, so if there is an attempt at a retrograding Scandinavian ridge later in Feb. there may not be a lot of interference. 

A few of the latest GFS runs have been trying to show just that, but I'd say its too far out to worry too much about now. 

 

[Carvers Gap]

56 minutes ago, Holston_River_Rambler said:

One thing about the strat. is that I don't see any signs of it strengthening again yet, so if there is an attempt at a retrograding Scandinavian ridge later in Feb. there may not be a lot of interference. 

A few of the latest GFS runs have been trying to show just that, but I'd say its too far out to worry too much about now. 

 

Is that a -NAO sig?

[Holston_River_Rambler]

36 minutes ago, Carvers Gap said:

Is that a -NAO sig?

Yep 

[Carvers Gap]

Nice slider at 96hour on the 12z GFS.

[Matthew70]

1 hour ago, Carvers Gap said:

Nice slider at 96hour on the 12z GFS.

Cliff hanger lol

[matt9697]

Judging by the activity in here I get the feeling that next weeks system is going poof

[Daniel Boone]

23 minutes ago, matt9697 said:

Judging by the activity in here I get the feeling that next weeks system is going poof

warmth

[Daniel Boone]

i wouldnt fret it as i think the cold will press more. 

[Daniel Boone]

Here ya go:

[Carvers Gap]

36 minutes ago, matt9697 said:

Judging by the activity in here I get the feeling that next weeks system is going poof

Nah.  12z update.... The CMC is a pretty bad ice event for middle and west.  The GFS is a nice 2-4" slider for much of the state north of I-40.  With so little agreement....I think we are all just chilling and waiting for some agreement.  Here are a few snapshots. The models are consistent within their own runs but now with each other....

 

[Matthew70]

Thing is warmth almost always verifies on models. 

[matt9697]

4 minutes ago, Carvers Gap said:

Nah.  12z update.... The CMC is a pretty bad ice event for middle and west.  The GFS is a nice 2-4" slider for much of the state north of I-40.  With so little agreement....I think we are all just chilling and waiting for some agreement.  Here are a few snapshots. The models are consistent within their own runs but now with each other....

 

Yea, I had forgotten about the canadian which has been sounding the alarm all week

[Daniel Boone]

1 minute ago, Carvers Gap said:

Nah.  12z update.... The CMC is a pretty bad ice event for middle and west.  The GFS is a nice 2-4" slider for much of the state north of I-40.  With so little agreement....I think we are all just chilling and waiting for some agreement.  Here are a few snapshots. The models are consistent within their own runs but now with each other....

 

Meant to mention that event Carvers. Guess I was looking on down the road a bit,lol.  Let's hope GFS is right regarding this one. Several on the MA forum are talking about GFS showing 2mT above freezing during the event. It actually is for most of the area. However, i'm not buying that as T should srop as precip falls at a decent rate. Of course, snow can accumulate above freezing if rates are heavy enough too.

[Carvers Gap]

Again, sometimes I just don't post if it is more of the same......my interests are medium and long range forecasting.  When it gets in the short range...I generally bow out.  Go look at many of the other threads.  I post some and usually in flurries...but once it is in close...I will post less.  Also, since E TN is less involved(many original founders of the forum are from there), middle and west are left to carry the load.  But yeah, PLENTY still to talk about.  It may go poof(I am not seeing that yet), but below is the CMC.  I think we are going to see a hot mess from the West Bank of the TN River to the MS.  It could press eastward from that point as well.  Modeling is all over the place right now.  I also tend to post fewer maps when pretty much each deterministic run is different from the other.  Maybe a slight trend northward today. 

 

[Carvers Gap]

Just now, Daniel Boone said:

Meant to mention that event Carvers. Guess I was looking on down the road a bit,lol.  Let's hope GFS is right regarding this one. Several on the MA forum are talking about GFS showing 2mT above freezing during the event. It actually is for most of the area. However, i'm not buying that as T should srop as precip falls at a decent rate. Of course, snow can accumulate above freezing if rates are heavy enough too.

Memphis mentioned time of day as a driver.  The bigger issue is a boundary that presses south, goes back north, and comes back south.   Throw in time of day....I mean, good luck to models and forecasters hitting that.  LOL.  

[Carvers Gap]

I mean w/ 100 yours to go...modeling is still not totally dialed in.  Take a look at the cold air anomalies with each run...they are all over the place.  Some runs are warmer, some aren't.........Just when I think it is trending in a predictable manner - u-turn.   The GEFS still continues to bang the drum for west TN ice - three impulses to be exact.

[Daniel Boone]

Yeah, with that boundary setting up in the vicinity Model's will have fluctuation's on what side we're on and what precip. Hopefully, the cold press is enough to allow for predominately snow. If we can score just one good one the way this winter has been, I'll be satisfied....well, somewhat, lol

[Carvers Gap]

7 minutes ago, Daniel Boone said:

Meant to mention that event Carvers. Guess I was looking on down the road a bit,lol.  Let's hope GFS is right regarding this one. Several on the MA forum are talking about GFS showing 2mT above freezing during the event. It actually is for most of the area. However, i'm not buying that as T should srop as precip falls at a decent rate. Of course, snow can accumulate above freezing if rates are heavy enough too.

Even the MJO is in flux city.  It seems like overnight modeling kind of leaned towards the Euro which has less warm tour and a quick return to phase 8.  But I remember looking at a CPC threats map for the western Pac - and phase 4-6 is lit w/ a typhoon if memory serves me correctly.  I think we will need to (to reference Cosgrove) have a strong front runner, enough spacing to drive the boundary behind it, and then a storm behind it once past Feb 5th.  Going to need a 1-2 combo after this over-running slop fest.

[Carvers Gap]

When looking at the long range....two paths diverge.  

[Carvers Gap]

One thing I will note is that modeling has overestimated the cold in the eastern Plains.  That mid Jan warm-up maybe lessened the snowpack there, and I wonder if that has something to do with that.  Friction (caused by low snow cover) will just eat a cold air mass alive.

[nrgjeff]

My two cents. Yes the cold will undercut. Mid South and western third of our Region could surprise one day next week. Upper Plateau could / should do so as well. I don't about the I-81 corridor though.

My other penny is that Chattanooga will stay well above freezing when it counts, so wake me up the next chance of severe. 

[Matthew70]

I will take the rain over ice any day.  We are heading to Gatlinburg for a soccer showcase.  I’m just fine with some rain.  Looks now it will be chilly but dry.  That sounds great! 

[Matthew70]

Tomorrow near 60 & Sunny then week after mid 50’s to 60.  Yeah not gonna complain.  Better than 33 & rain. 

[Carvers Gap]

For me, this winter is a carbon copy of the last three.  Chances during December along w/ severe cold.  Then, it was a battle from that point onward, but not without opportunities.   I think for folks west of the Plateau, this winter (still been better than mine) has been similar to what E TN has seen for three straight seasons.  That may be why E TN folks are somewhat apathetic to warmer temps and fewer chances.  

 

Taking a look at next season, the QBO should be dropping and that is big.  Right now it is rising, and very few good winters in TN correlate to a rising QBO.  In fact, most great winters correlate to -QBOs.   The wild card is just how strong that Nino is going to be.  If it is a super Nino, my winter forecast will be AN(or much above) for the entire season.  If it is a weak Nino, then we have chances during Jan-Feb especially.  What I am excited about is that summer should not be hot and dry like it was w/ La Nina.  On the negative side, that could mean that spring will be delayed.  I am hopeful that the cold gradient laid down by three straight Nina winters will help to accentuate Nino climatology instead of wash it out as the previous Nino was.  Also, I do suspect that we see an increased number of -NAO years, including next winter.  That is a good combination as the NAO emphatically gave us our coldest part of the season this winter.  

 

As for the rest of winter, I think we have chances next week.  Then, we see a BIG warm-up.  See the very first post of this thread.  It shouldn't be a shock.  Of comfort, sometimes when I call for a big warm-up...it does the opposite.  So, I am not changing my tune and maybe we get some reverse mojo.  I do think we have one last window from the last week of February through mid-March...then a full on break towards spring....

[Carvers Gap]

1 hour ago, nrgjeff said:

My two cents. Yes the cold will undercut. Mid South and western third of our Region could surprise one day next week. Upper Plateau could / should do so as well. I don't about the I-81 corridor though.

My other penny is that Chattanooga will stay well above freezing when it counts, so wake me up the next chance of severe. 

Good to see you posting again, man.  March Madness will be coming soon.  When UT goes to UK for a game, expect to be cold.  Weird teleconnection there.

[Daniel Boone]

50 minutes ago, Carvers Gap said:

For me, this winter is a carbon copy of the last three.  Chances during December along w/ severe cold.  Then, it was a battle from that point onward, but not without opportunities.   I think for folks west of the Plateau, this winter (still been better than mine) has been similar to what E TN has seen for three straight seasons.  That may be why E TN folks are somewhat apathetic to warmer temps and fewer chances.  

 

Taking a look at next season, the QBO should be dropping and that is big.  Right now it is rising, and very few good winters in TN correlate to a rising QBO.  In fact, most great winters correlate to -QBOs.   The wild card is just how strong that Nino is going to be.  If it is a super Nino, my winter forecast will be AN(or much above) for the entire season.  If it is a weak Nino, then we have chances during Jan-Feb especially.  What I am excited about is that summer should not be hot and dry like it was w/ La Nina.  On the negative side, that could mean that spring will be delayed.  I am hopeful that the cold gradient laid down by three straight Nina winters will help to accentuate Nino climatology instead of wash it out as the previous Nino was.  Also, I do suspect that we see an increased number of -NAO years, including next winter.  That is a good combination as the NAO emphatically gave us our coldest part of the season this winter.  

 

As for the rest of winter, I think we have chances next week.  Then, we see a BIG warm-up.  See the very first post of this thread.  It shouldn't be a shock.  Of comfort, sometimes when I call for a big warm-up...it does the opposite.  So, I am not changing my tune and maybe we get some reverse mojo.  I do think we have one last window from the last week of February through mid-March...then a full on break towards spring....

Spot on with that Post Carver ! Weak Nino is always our best shot at a cold/snowy Winter. Weak Nina's can be decent but, strong either way is killer.