Potential Big Dog Snow Event February 15th

[Carvers Gap]

12z CMC is a moderate event scaled back from earlier versions. Looks remarkably like the 12z GFS. The UKMET I hear holds fast to the western envelope of the event. Time for Dr No.

[tnweathernut]

12z CMC is a moderate event scaled back from earlier versions. Looks remarkably like the 12z GFS. The UKMET I hear holds fast to the western envelope of the event. Time for Dr No.

The UKMet is probably rain for Buffalo....

[Runman292]

The UKMet is probably rain for Buffalo....

What am I looking at here? I don't know how to read that model.

[Carvers Gap]

What am I looking at here? I don't know how to read that model.

 

Instead of the slp tracking through the MS, AL, and GA...the UKMET goes well north and west vs the 12z GFS, 12z Canadian, and 0z Euro Para.  That would be most likely a front end thump of snow and sleet followed by freezing rain and rain - but mostly rain.  But almost no accumulation unless one depends on wrap-around snow.  Not a good look for snow in the forum area.  Good example of what happens if that high pressure slides off the coast too quickly.  It is a reasonable possibility along w/ the Canadian/Para one.  It is important to see what camp the Euro op is in...if it goes to the UKMET like it did at 0z, then it is time to look at the real possibility that the UKMET is right.  Just a hunch, but I believe the 12z Euro comes back southeast due to it being so removed from the EPS.  But the 12z UKMET can sometimes give us a clue to the 12z Euro.  So, I have low confidence in my hunch.

[John1122]

FWIW the WPC dismisses entirely the UKMET as being the most unlikely solution. It says the 00z Euro op is the next most unlikely. It's currently going with a blend of the Euro Ensembles and I think GFES. 

[Carvers Gap]

FWIW the WPC dismisses entirely the UKMET as being the most unlikely solution. It says the 00z Euro op is the next most unlikely. It's currently going with a blend of the Euro Ensembles and I think GFES. 

 

John, bringing it today!  12z Euro rolling...

[John1122]

Out to 108 on the Euro. High is a little stronger and maybe 100-150 miles further West than 00z. Storm is over North Texas in about the same location as 00z.

[John1122]

The LP in Canada is also around 150-200 miles further North vs the 00z run. Looks similar to 00z otherwise.

[John1122]

I'm gonna guess this run will be similar to the 00z run based on where things are now.

[jaxjagman]

I'm gonna guess this run will be similar to the 00z run based on where things are now.

Faster isnt it?

[Carvers Gap]

Very similar.  Some meso highs did appear 108 through 126.  If that precip streams in earlier, we are looking at an outright mess.

[Carvers Gap]

12z Euro.  Snow axis runs the length of the Ohio River. Edit:  northwest TN does see some nice amounts along the KY boarder. 

[John1122]

It was actually a huge huge shift. It's at least 400 miles south of 00z. It's just not quite far south enough yet. Will see what the EPS/Para shows. But I really like the big shift south.

[Stovepipe]

It'll be interesting to see the low clusters on the EPS later this afternoon.

[weathertree4u]

It was actually a huge huge shift. It's at least 400 miles south of 00z. It's just not quite far south enough yet. Will see what the EPS/Para shows. But I really like the big shift south.

Looks like the heaviest snow axis shifted north, are you expecting that to settle south again?

[John1122]

Where the 00z had the LP in central Ohio, 12z has it in Northern Alabama. Where the 00z had it in Pennsylvania, the 12z has it sitting on Mt Leconte.

 

The clown is almost the same as 00z. 2-4 inches from the Plateau and points west, getting higher towards nw TN. The axis of heavy snow shifted further into Kentucky by a bit.

 

I think we'll probably see it shift more south again tonight. It's Ensembles being in Mobile Alabama last night with the OP in Central Ohio made no sense at all.

[Stovepipe]

12z GEFS has about 7 nice hits, 7 misses, and 7 middle of the road clowns.

 

Edit:  What a middle of the road clown may look like:

 

[Carvers Gap]

The low itself is south.  The snow axis runs the length of the Ohio river.  The axis in the NE might be slightly east and south of 0z.  Otherwise, the snow axis is almost identical but it expanded as the 12z had a much stronger low over northern Alabama.  It also transfers that low to the coast.  It is almost like it can't decide to cut west of the Apps as an inland runner Miller B or to go back to the original solution that was basically overrunning w/ a Miller A track.  The stronger low over Alabama would create waa over most of the Valley.  Some back end snow over middle TN where they get 2-3" of it.  Not a good run if you like snow...but better than 0z in the low placement, but worse that it is stronger even though south.  With those HPs scooting out so quickly, going to be tough to see winter wx in the eastern 2/3 of the forum area.  Edit: The far northwest corner of TN gets a good snow along the TN/KY border.

 

Now, here is the question that I have for those that know the micro-climate in the eastern Valley.  Those mesoscale HPs in the eastern Valley from 108-126 are creating some mischief.  Have to think w/ overrunning that the precip gets ahead of model guidance.  I am thinking a quick burst of snow, then to sleet, and then here is the question...Does the cold air get trapped in the Valley?  If that low is weaker, it could happen.  If it does, then ice we have.  Potentially could move in Sunday night?

[franklin NCwx]

12z GEFS has about 7 nice hits, 7 misses, and 7 middle of the road clowns.

Edit: What a middle of the road clown may look like:

Looks like a crack head dressed as a clown.

[John1122]

The low itself is south.  The snow axis runs the length of the Ohio river.  The axis in the NE might be slightly east and south of 0z.  Otherwise, the snow axis is almost identical but it expanded as the 12z had a much stronger low over northern Alabama.  It also transfers that low to the coast.  It is almost like it can't decide to cut west of the Apps as an inland runner Miller B or to go back to the original solution that was basically overrunning w/ a Miller A track.  The stronger low over Alabama would create waa over most of the Valley.  Some back end snow over middle TN where they get 2-3" of it.  Not a good run if you like snow...but better than 0z in the low placement, but worse that it is stronger even though south.  With those HPs scooting out so quickly, going to be tough to see winter wx in the eastern 2/3 of the forum area.  Edit: The far northwest corner of TN gets a good snow along the TN/KY border.

 

Now, here is the question that I have for those that know the micro-climate in the eastern Valley.  Those mesoscale HPs in the eastern Valley from 108-126 are creating some mischief.  Have to think w/ overrunning that the precip gets ahead of model guidance.  I am thinking a quick burst of snow, then to sleet, and then here is the question...Does the cold air get trapped in the Valley?  If that low is weaker, it could happen.  If it does, then ice we have.  Potentially could move in Sunday night?

 

 

I'm in no way convinced this won't be a miller A type track yet. I'm not convinced it will not be a cutter either. I am reasonably certain that the LP won't track over LeConte as depicted on that run.  Right now the Euro OP can't be trusted at all, 3 runs and it's moved the system all over creation after doing so well with keeping a consistent solution leading into the last 12 hours. It's Ensembles have so far kept the consistent solution, will know soon if they did this afternoon again.

[John1122]

The updated WPC track should be very very good for us if it were to come to pass. Central Louisiana to South Central South Carolina and not very majorly wound up.

 

Their take on actual weather during this period.

 

 

 

PREVAILING CHILL LINGERS ACROSS THE EASTERN THIRD OF THE NATION
HEADING INTO MONDAY MORNING ---AND THE COLD CANADIAN SURFACE RIDGE
IS STUBBORNLY RETREATING (NORTHEASTWARD) ALONG THE NORTHEAST COAST
AND GULF OF MAINE---EVEN OUT TO DAY 5-6. BECAUSE OF THE STUBBORN
SURFACE RIDGE AND ENTRAINMENT OF MOISTURE AND ENERGY ALONG THE
SOUTHERN AND WESTERN FLANKS (AND ATOP) THIS RIDGE--- EXPECT SOME
LOCALLY MODERATE-TO-HEAVY CONCENTRATIONS OF OVER-RUNNING
PRECIPITATION (AND WINTRY P-TYPE SCENARIOS) WITH EMBEDDED ENERGY
APPROACHING FROM TWO DIRECTIONS...THE GREAT LAKES (A MID-LEVEL
FOCUS) AND THE NORTHEAST GULF OF MEXICO (A LOW-LEVEL FOCUS).

[franklin NCwx]

I'm in no way convinced this won't be a miller A type track yet. I'm not convinced it will not be a cutter either. I am reasonably certain that the LP won't track over LeConte as depicted on that run. Right now the Euro OP can't be trusted at all, 3 runs and it's moved the system all over creation after doing so well with keeping a consistent solution leading into the last 12 hours. It's Ensembles have so far kept the consistent solution, will know soon if they did this afternoon again.

it did trend away from an amped up cutter at 0z. We need another shift or two like that.

[Carvers Gap]

I'm in no way convinced this won't be a miller A type track yet. I'm not convinced it will not be a cutter either. I am reasonably certain that the LP won't track over LeConte as depicted on that run.  Right now the Euro OP can't be trusted at all, 3 runs and it's moved the system all over creation after doing so well with keeping a consistent solution leading into the last 12 hours. It's Ensembles have so far kept the consistent solution, will know soon if they did this afternoon again.

 

The run made a lot of sense until it tried to run the spine of the Apps.  The meso highs were in place.  High pressure was sliding off quickly to the north.  Waa was taking place.  Much of that was in our favor(meso highs were in our favor), but it made sense.  But when it made a run up the spine of the apps...that was wonky.  It was like it came to a fork in the road and didn't take either fork.  I wouldn't say it can't be trusted.  It maintained continuity w/ 0z and w/ the UKMET which for three straight runs has gone west. (I know the wpc tossed it, but that doesn't make it wrong) That is a strong combo and a combo that has lost few battles this winter.  It is closer to the event, and the Euro may be adjusting.  Also, the northern stream energy may now be getting sampled better (or it may be in a blind spot over the northern Pacific), but the models should come into agreement earlier than the DC blizzard because the energy is in the northern jet and will be over NA longer.  The only model that has maintained a consistent solution is the Canadian op (not its ensembles).  So, we have two camps...The 12z Euro/12z UKMET vs the 12z GFS, 12z GEFS, 12z Canadian, 0z EPS, 0z Para.  Some of those pieces will move around today.   I feel less confident today of a moderate snow event for the eastern 2/3 of the Valley.  But like John, am by no means jumping ship.  

 

John, what are your thoughts on potential icing?  That is a growing concern of mine.  The northern Valley is notoriously fickle in allowing Arctic air to be scoured out....

[Carvers Gap]

The updated WPC track should be very very good for us if it were to come to pass. Central Louisiana to South Central South Carolina and not very majorly wound up.

 

Their take on actual weather during this period.

 

So, their maps are updated?  If so, they like the weak miller A that strengthens over the Piedmont?  That would be a perfect track.

[Stovepipe]

WPC Day 5:

 

 

Day 6:

 

[John1122]

So, their maps are updated?  If so, they like the weak miller A that strengthens over the Piedmont?  That would be a perfect track.

Yes, they updated their maps at 10:30 this morning. 

 

I don't personally see the consistency on the Euro you spoke of earlier. I can't take a model with 3 runs and storm placements 400 miles apart on each run as consistent with anything other than that it's showing a storm.

 

I do agree that any solution could be right. But in reading the HPC disco, they explain why they think the UK is wrong. They looked at the model data from 00z/06z and then hand drew that track from Louisiana to the midlands of South Carolina based on their thinking of how the track of the low should be based on their experience. Matthew East also had that track. If you look it's right down the middle of the Euro and Canadian/GFS almost. 

 

WPC also gave some decent weight to the Canadian fwiw, which gets us all and bombs East Tennessee with 6-10 inches.

[Carvers Gap]

WPC Day 5:

WPC Day 6:

 

Any idea if those are this afternoon's maps?  Those time stamps throw me off every time...

 

Edit:  Nevermind...John got it above.  Will be interesting to see how they factor-in the 12z suite.

[franklin NCwx]

Those maps look like the Euro ensemble mean low track.

[Carvers Gap]

Yes, they updated their maps at 10:30 this morning. 

 

I don't personally see the consistency on the Euro you spoke of earlier. I can't take a model with 3 runs and storm placements 400 miles apart on each run as consistent with anything other than that it's showing a storm.

 

I do agree that any solution could be right. But in reading the HPC disco, they explain why they think the UK is wrong. They looked at the model data from 00z/06z and then hand drew that track from Louisiana to the midlands of South Carolina based on their thinking of how the track of the low should be based on their experience. Matthew East also had that track. If you look it's right down the middle of the Euro and Canadian/GFS almost. 

 

WPC also gave some decent weight to the Canadian fwiw, which gets us all and bombs East Tennessee with 6-10 inches.

 

The problem right now is we don't know which model is right.  If the 12z Euro switched continuity due to better data and ends-up nailing the track, then it will be consistent as it will potentially hold that track for the next five days.  Which reminds me, this is still outside of five days.  And if the track is well to the west, none of the other models will be even close to that track.  If it turns out that the slider scenario is reality, then obviously the Euro waffled.  Too early to tell.  The EPS may shed some light on this as well. 

 

Will check-out WPC later today.  I always enjoy their write-ups and don't read them enough lately.  I am about 50/50 on whether this cuts or takes the WPC track.  If I was forced to make a call I would take the wpc track because it makes sense.  Literally the UKMET and Euro both take the energy from north Dakota south to the arklatex region(that is off the top of my head) and then bring it north immediately in what is a very tight parabola.  Those don't happen often in the weather world I agree.  If the energy was coming out of the southwest, I could see that track.  But seems the frequency of the trough is too tight on the Euro and UKMET.  They almost stall the energy out over TX and that allows the slp to track through TN.  If the energy swings down like the GFS(just now came to the party) and the Canadian, then it should slide across more. 

 

Jax asked this question earlier and it was a good one.  I think, Jax, that the 12 Euro was a tad slower than the 0z.  I toggled the hours on WxBell(great feature by the way) and it looks a touch slower.  Might be that the slower solutions are causing the cut and the faster ones are sliding across w/ overrunning. 

 

All of that said, what are the model biases at this point.  Does the Euro have a habit of slowing things down too much at this stage?  Is the GFS too progressive at this stage? 

[Carvers Gap]

Those maps look like the Euro ensemble mean low track.

 

So, the EPS is in?  In transit at the moment...