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

[John1122]

Kept waiting on someone else to start a February thread but it didn't quite come to fruition. Hopefully the frigid possibility is not a head fake and we get some real valley wide storm threats to go along with it.

[John1122]

I will say this, the never ending NAO has prevented torch fest but the meh at best Pacific has prevented any Arctic invasion. We got a favorable Pacific briefly around Christmas and it got cold for all and snowy for a lot of us. I also have noticed as I am sure we all have, the models keep pushing for the SE ridge to return and have almost all winter in the long range but when it comes time, it never quite materializes. But because the Pac isn't favorable we have too much warm air to quite stay frozen with most systems. The best case scenario for us is a suppressed track driven by a cooperative NAO/AO/Pacific and we get over running slider events that snow from Arkansas to North Carolina. Other ways are that massive cold bulge coming east enough to keep us on the cold side while systems form on it because of the SE ridge. It's a fine line but when you get that Arctic air lucking nearby you have to start watching for ice events, especially from the Plateau and westward. SE ridge + frigid Midwest is a setup where it's raining and 50 in the Tri-Cities and 28 and freezing rain in Memphis at times. You just never know where the front will stall, but stalling against the Apps is somewhat common in that scenario.

[John1122]

Dr. No is actually more Dr. Yes than most for the snow potential Sunday night and into early week.

[John1122]

Basically the entire 06z suite is on board with the 0z Euro. MRX remains typically bearish outside the mountains, where they will likely issue a WSW by tomorrow, as they are bullish there. They mention 1200 feet as the likely snow line but also say most of the valley will see some snow in the air. 

To date this year I've had a lot of over performers imby with one bust, that being a couple days ago with the dusting. 

[Holston_River_Rambler]

I know they're talking about the mountains in this quote, but still nice to see:

"It`s too far out to discuss accumulation details just yet
but I suspect there will be some notable snowfall totals out of this
storm."

 

It really does look like more than your average NW Flow. Check out the vort lobe fujiwara on the NAM:

\

 

The 6z Euro has it too:

 

 

 

[fountainguy97]

1 hour ago, Holston_River_Rambler said:

I know they're talking about the mountains in this quote, but still nice to see:

"It`s too far out to discuss accumulation details just yet
but I suspect there will be some notable snowfall totals out of this
storm."

 

It really does look like more than your average NW Flow. Check out the vort lobe fujiwara on the NAM:

\

 

The 6z Euro has it too:

 

 

 

When the 06z 12km NAM is dropping a foot in the great smoky mountains its going to be legit.

models are beefing up this overunning band this afternoon. 3km is dropping a quick inch across NE TN.  We have also beaten low temps here by miles the past 2 nights. 

 

[1234snow]

When the 06z 12km NAM is dropping a foot in the great smoky mountains its going to be legit.

models are beefing up this overunning band this afternoon. 3km is dropping a quick inch across NE TN.  We have also beaten low temps here by miles the past 2 nights. 
 

Good catch on the overrunning band. The NAM has had it for a few cycles. More enthusiastic than RGEM.

[Shocker0]

5 hours ago, John1122 said:

Basically the entire 06z suite is on board with the 0z Euro. MRX remains typically bearish outside the mountains, where they will likely issue a WSW by tomorrow, as they are bullish there. They mention 1200 feet as the likely snow line but also say most of the valley will see some snow in the air. 

To date this year I've had a lot of over performers imby with one bust, that being a couple days ago with the dusting. 

Pretty much the same here. Every snow has been around 2-4 inches consistently until the one bust the other day. Still the best winter here in 5 years or so though.

[Shocker0]

TWC now says 1-3" tomorrow night here and the same Monday. With "less than one inch" Monday night. Hopefully that verifies, they ended up being right avoht the bust in my location last week.

[John1122]

It was 16 this morning and is still below freezing here.  2 days in a row in the teens, then cold rain falling should have ground Temps fairly set for this. 

[tnweathernut]

MRX seemingly overplayed the last system, even when data was indicating reasons to be cautious wrt snow (in east and northeast TN).  This may cause them to overreact and be too cautious on the early week snow potential.  I realize they have time on their side and it seems minor”ish”, but it’s been really cold leading up to this system .......and although we go warm for the first part, most of what falls after sundown with the upper level support passing almost directly over us Monday night into Tuesday morning could cause many more problems for commuters Tuesday.  
 

In short, vs the last system, I think this one has much more potential for impacting travel.

[Icy Hot]

1 hour ago, tnweathernut said:

MRX seemingly overplayed the last system, even when data was indicating reasons to be cautious wrt snow (in east and northeast TN).  This may cause them to overreact and be too cautious on the early week snow potential.  I realize they have time on their side and it seems minor”ish”, but it’s been really cold leading up to this system .......and although we go warm for the first part, most of what falls after sundown with the upper level support passing almost directly over us Monday night into Tuesday morning could cause many more problems for commuters Tuesday.  
 

In short, vs the last system, I think this one has much more potential for impacting travel.

But MRX is only showing a 30% chance of Snow Monday night. 

[Daniel Boone]

1 hour ago, tnweathernut said:

MRX seemingly overplayed the last system, even when data was indicating reasons to be cautious wrt snow (in east and northeast TN).  This may cause them to overreact and be too cautious on the early week snow potential.  I realize they have time on their side and it seems minor”ish”, but it’s been really cold leading up to this system .......and although we go warm for the first part, most of what falls after sundown with the upper level support passing almost directly over us Monday night into Tuesday morning could cause many more problems for commuters Tuesday.  
 

In short, vs the last system, I think this one has much more potential for impacting travel.

My thoughts exactly.  A bust like this last system has a tendency to cause that especially with ones that are typically conservative anyway.

       Models all have my area getting a couple inches tonight. 12z NAMS nuts with its 5 to 6" depiction.  Not buyingbit but will say I've witnessed a fall of 5" with a similar setup.  Dec., 5,  2003.

     Also 4" from a very similar h5 setup in the late 80s. 

[tnweathernut]

12z Euro keeps a decent little event going overnight Monday and into Tuesday.....


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[Holston_River_Rambler]

I'm impressed with how the big frontal passage on the 4 - 5 has trended the past couple of days. Something with t-storm potential, to overrunning:

 

 

 

 

 

[Daniel Boone]

If we can get a semblance of sustained ridging out west I believe we'd all be in business for a widespread Winter Storm .  I have a gut feeling of a Major b4 Seasons over. 

   Hopefully, I won't have to take a lot of milk of magnesia at season's end.

[Shocker0]

Sleet storm in Crossville currently

 39° at my house

[PowellVolz]

Monday is looking interesting


.

[John1122]

8 minutes ago, PowellVolz said:

Monday is looking interesting


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MRX mentions NNW flow. I do well with that and Walnut and Black Mountain here will generate a band that reaches north Knox at times in NNW flow. 

[Carvers Gap]

0z GFS easily has the coldest air mass of the season after 150.  West TN gets some digital snow on that run as well.  Low single digits around 200.

[Carvers Gap]

I know we are looking at M/T stuff, but next weekend is not without promise.  Timing is a bit different on each, but both the Euro and GFS(old and new) show something along the front as it sags through our area.  

The EPS has finally seen the light, and the 6z EPS pushes a strong cold front through just after the 6th.  I would also suspect we have a legit shot a clipper with this cold and then maybe a WAA system as it departs.  Operational models are definitely colder than the ensembles of each model overnight.  Makes me think the ensembles are playing catch-up.  The ensembles seem to have been very slow to adjust to the actual pattern.  

Some fun facts, the MUO is gaining amplitude in phase 6 which is normally very warm.  If we get snow in phase 6, enjoy that!  Doesn't happen often.  One would think that the wave in 6 is going to propagate to the dateline and get us to phase 8.  The CHI map yesterday shows that and then has precip over Eastern Africa which would imply phase 1-2 of the MJO.  So, I would suspect modeling and MJO charts to at least "try" to get the MJO in colder phases.  Honestly, as long as that block is over Greenland modeling is likely to struggle.  As wavelengths shorten(due to spring approaching at this latitude in 4-5 weeks...think it will be a bit late), modeling is going to struggle with that as well, especially the EPS(shoulder season issues).  

Somebody remind me, does the NAO have a great impact early, mid, or late season in terms of cold/snow?

 

[Holston_River_Rambler]

Dr. Schmaybe and the CMC showing a storm around 160 hours. 

 

Dr. Schmaybe:

 

The Canuck:

[Holston_River_Rambler]

Dr. Schmaybe's naught bits (includes upslope event the next couple of days):

 

Evolution on the Euro:

 

 

 

[Holston_River_Rambler]

Euro is going to be close to another really nice event towards the end of it's run, but not quite sure how it will evolve as the run plays out. 

[snowmaker]

All my snowchips are in on the upcoming 2 weeks, if appears that true cold may indeed get involved and a overrunning pattern could very develop along the boundary with systems running along it. Here's especially hoping for areas of west and middle tn north of I-40 we haven't gotten much more than a flurry for the most part. But I think the entire state will has the opportunity in the coming 2 weeks. Good luck everyone and keep your thought coming I love to read them and enjoy the info.

[Carvers Gap]

Just checking in to make sure everyone is doing well after that snoozer of a 12z suite.....

[Carvers Gap]

Seriously,  Wow.  The CMC was nuts and so was the GFS.  That CMC look at 240...after it had already brought snow with with the earlier storm.  Looks like modeling is trending slightly further south with the freezing line.  Good sign.  

[Carvers Gap]

The 12z Euro for the next 10 days...that is insane.  Kuchera.  Smokies w/ nearly 40."  

[Holston_River_Rambler]

Interesting end to the Euro. Looked really good, except for the energy over the Lakes. That was left over from and earlier storm. Unclear if it would end up suppressing the STJ energy or phasing with it, since there was even more energy dropping in through the Dakotas:

 

Just looking at the precip map, not sure I've ever seem any map as pretty as what the OP Euro was showing at its end. Anticipation is the best part, after all, lol. This is the kind of stuff that is usually just on one EPS member. 

[Carvers Gap]

The 12z GEFS mean and GEPS means are bonkers.  The GEPS has 2"+ mean for all of TN and into norther MS and AL. GEFS isn't far from that.  EPS is roiling now.  Let's see if we can hold onto that signal.  Could be a blip, but wow...what a blip if so.