Potential Big Dog Snow Event February 15th

[Mrwolf1972]

The guy on AccuWeather said don't pay attention to the models they will sway back and forth the next few days mainly look for a path in-between.

[John1122]

MRX released their afternoon disco, pretty much says Northern counties/SWVA/Mountains get significant snow. Some freezing rain in the southern Plateau, mountain valleys, everyone rains some, then back to snow, back to rain, back to snow etc.

[John1122]

The current graphic.

 

[Runman292]

The current graphic.

That's from yesterday.

[John1122]

Just noticed that was from 6:45 yesterday morning. They've changed their minds for whatever reason to much more rain Monday night. 

[John1122]

That's from yesterday.

I just noticed it was, they have it as the headline on the site right now.

 

For whatever reason when the models looked worse they forecast that, the models look better now and they forecast more rain. I guess that's why they get paid to do it.

[ShawnEastTN]

Just noticed that was from 6:45 yesterday morning. They've changed their minds for whatever reason to much more rain Monday night. 

For now...  I suspect over the next 24 hours that will change again.  I really think they are waiting for GFS to buy a colder solution and spooked by the warm Euro.

[JayCee]

Sounds like a now cast event come Monday.  Considering differences in elevation and "micro-climates" in East TN, this is going to be a very volatile and changeable winter event in the extreme.  I don't envy MRX.  No way to get everyone's forecast correct. 

[Stovepipe]

18z GFS looking good for the initial thump of snow.

 

It seems to show the cold air trapped in the eastern valley for a good bit.

 

Goes to rain for most.  Some initial ice in east TN.

[Stovepipe]

18z GFS clown:

 

[Mrwolf1972]

The 18 gas doesn't really show a True lb on the map but shows a lap hit Tuesday night with rain that's new

[ShawnEastTN]

I wonder if we are seeing a trend here, seeing the GFS linger frozen precipitation longer in the valley. Also maybe a trend to a faster tracking storm with lighter precip totals in general.

[franklin NCwx]

Gfs is a frontal passage. Lol... It looks like happy hour on a Friday.

[tnweathernut]

Gfs is a frontal passage. Lol... It looks like happy hour on a Friday.

I don't buy the frontal passage look.  I think the trough goes negative tilt somewhere in the southeast and I just hope it's not too far west to flood us with warm air.

[John1122]

It has no southern development, just ends up an amped up clipper.

[Runman292]

This might be one of those 18z GFS runs that you have to take with a huge grain of salt.

[ShawnEastTN]

So hmmm... What's on the table now? Euro blowtorch cutter, NAM speedy Gonzalez, GFS what storm I'm just a ripple in the flow, or Canadian & Ukie consistent low across the deep south rounding the bend east of Apps. We certainly have more options than a Chinese buffet.... Surly by 0Z tonight we should start seeing some agreement somewhere besides Canadian and Ukie.

[kvskelton]

MRX disco from this afternoon:

 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
328 PM EST FRI FEB 12 2016

LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)... WINTER CONTINUES IN
FULL FORCE SATURDAY NIGHT AS COLD ARCTIC AIR MASS AND MOSTLY CLEAR
SKIES SATURDAY EVENING AND LIGHT SNOW COVER STILL POSSIBLE WILL
ALLOW OPTIMAL COOLING. LOWS EXPECTED TO BE IN THE SINGLE DIGITS AND
TEENS. UPPER TROUGH REMAINS OVER THE EASTERN STATES THROUGH MID WEEK
AND ANOTHER WEATHER SYSTEM WILL APPROACH THE AREA SUNDAY AFTERNOON.
MODELS ARE SPEEDING THIS SYSTEM UP A FEW HOURS SO INCREASED POPS
SUNDAY IN THE AFTERNOON. A SHORTWAVE MOVES OUT OF THE MS VALLEY
SUNDAY WITH INCREASING MOISTURE COMING IN ON BACK SIDE OF ARCTIC
HIGH. TEMPERATURES WILL BE MODERATING FROM A COLD MORNING BUT
TRAPPED COLD AIR SHOULD RESULT IN SOME LIGHT SNOW ON THE NORTHERN
PLATEAU AND SOUTHWEST VIRGINIA SPREADING INTO THE CENTRAL VALLEY
LATE IN THE DAY ONLY EXPECTING A FEW TENTHS ACCUMULATION. MAIN AXIS
OF PRECIPITATION WITH THE SYSTEM MOVES IN SUNDAY NIGHT AND MONDAY.

WITH THE WARM ADVECTION PATTERN AHEAD OF THIS SYSTEM A MIXED BAG OF
PRECIPITATION IS POSSIBLE SUNDAY NIGHT AND MONDAY. HIGHS SUNDAY IN
THE SOUTHERN PART OF THE AREA SHOULD REACH THE MID 30S TO AROUND 40.
OVERNIGHT SUNDAY NIGHT TEMPERATURES WILL BE SLOW TO FALL WITH THE
WARM AIR MOVING IN BUT ENOUGH WARM AIR WILL BE IN PLACE FOR SOME
FREEZING RAIN OR SLEET TO FALL IN SUB FREEZING AREAS OUTSIDE OF THE
NORTHERN AREAS WHERE THERE WILL BE MOSTLY SNOW. LIGHT RAIN WILL BE
PREVALENT IN WARMER AREAS OF THE SOUTHERN VALLEY. ON MONDAY THIS
PROCESS WILL CONTINUE IN THE MORNING BUT SHIFT FARTHER NORTHEAST AND
TOWARD THE APPALACHIANS WITH RAIN REPLACING WINTER PRECIPITATION
FROM THE SOUTHWEST TO NORTHEAST. PREFER THE MUCH COLDER MAX
TEMPERATURES OF THE GFS FOR HIGHS MONDAY MOSTLY MID 30S TO NEAR 40.
ICING FROM ABOUT 0.1 TO 0.25 INCHES IS POSSIBLE SUNDAY NIGHT AND
MONDAY MORNING BEFORE TEMPERATURES WARM ABOVE FREEZING ESPECIALLY
SOUTHERN PLATEAU...AND EASTERN TN MOUNTAIN VALLEYS WHERE COLD AIR
BECOMES TRAPPED.

SIGNIFICANT SNOWFALL IS POSSIBLE IN THE EASTERN MOUNTAINS AND
NORTHERN TENNESSEE COUNTIES AS WELL AS SW VIRGINIA WHERE THE
ATMOSPHERIC PROFILE IS COLDER SUNDAY NIGHT AND WARMS UP LATER
MONDAY. THE SYSTEM WILL SHIFT TO THE EAST MONDAY NIGHT AND TUESDAY
AND COLDER AIR WILL GRADUALLY BE PULLED SOUTH INTO THE FORECAST
AREA. THE RAIN WILL CHANGE OVER TO A WET SNOW LATER MONDAY NIGHT
INTO TUESDAY MORNING. BY AFTERNOON TUESDAY TEMPERATURES WARM ABOVE
FREEZING TO THE 40S LOWER ELEVATIONS AND SNOW WILL CHANGE TO RAIN
EXCEPT AT HIGHER MOUNTAIN LOCATIONS WHICH SHOULD GET MORE MEASURABLE
WET SNOW.

ANOTHER QUICK MOVING SYSTEM MOVES SOUTHEAST THROUGH THE UPPER TROUGH
TUESDAY NIGHT AND WEDNESDAY. THIS KEEPS THE THREAT FOR SNOW SHOWERS
AT NIGHT AND RAIN DURING THE DAY. THE UPPER TROUGH FINALLY SHIFTS
EAST WITH UPPER LEVEL RIDGING MOVING IN THURSDAY AND FRIDAY.
TEMPERATURES WILL BE CONSIDERABLY WARMER DURING THE DAY WITH SUN
RETURNING. HIGHS THURSDAY EXPECTED TO BE IN THE MID 40S NORTH TO
UPPER 50S SOUTH...THEN 50S TO LOWER 60S FRIDAY.

[Runman292]

MRX disco from this afternoon:

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE MORRISTOWN TN

328 PM EST FRI FEB 12 2016

LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)... WINTER CONTINUES IN

FULL FORCE SATURDAY NIGHT AS COLD ARCTIC AIR MASS AND MOSTLY CLEAR

SKIES SATURDAY EVENING AND LIGHT SNOW COVER STILL POSSIBLE WILL

ALLOW OPTIMAL COOLING. LOWS EXPECTED TO BE IN THE SINGLE DIGITS AND

TEENS. UPPER TROUGH REMAINS OVER THE EASTERN STATES THROUGH MID WEEK

AND ANOTHER WEATHER SYSTEM WILL APPROACH THE AREA SUNDAY AFTERNOON.

MODELS ARE SPEEDING THIS SYSTEM UP A FEW HOURS SO INCREASED POPS

SUNDAY IN THE AFTERNOON. A SHORTWAVE MOVES OUT OF THE MS VALLEY

SUNDAY WITH INCREASING MOISTURE COMING IN ON BACK SIDE OF ARCTIC

HIGH. TEMPERATURES WILL BE MODERATING FROM A COLD MORNING BUT

TRAPPED COLD AIR SHOULD RESULT IN SOME LIGHT SNOW ON THE NORTHERN

PLATEAU AND SOUTHWEST VIRGINIA SPREADING INTO THE CENTRAL VALLEY

LATE IN THE DAY ONLY EXPECTING A FEW TENTHS ACCUMULATION. MAIN AXIS

OF PRECIPITATION WITH THE SYSTEM MOVES IN SUNDAY NIGHT AND MONDAY.

WITH THE WARM ADVECTION PATTERN AHEAD OF THIS SYSTEM A MIXED BAG OF

PRECIPITATION IS POSSIBLE SUNDAY NIGHT AND MONDAY. HIGHS SUNDAY IN

THE SOUTHERN PART OF THE AREA SHOULD REACH THE MID 30S TO AROUND 40.

OVERNIGHT SUNDAY NIGHT TEMPERATURES WILL BE SLOW TO FALL WITH THE

WARM AIR MOVING IN BUT ENOUGH WARM AIR WILL BE IN PLACE FOR SOME

FREEZING RAIN OR SLEET TO FALL IN SUB FREEZING AREAS OUTSIDE OF THE

NORTHERN AREAS WHERE THERE WILL BE MOSTLY SNOW. LIGHT RAIN WILL BE

PREVALENT IN WARMER AREAS OF THE SOUTHERN VALLEY. ON MONDAY THIS

PROCESS WILL CONTINUE IN THE MORNING BUT SHIFT FARTHER NORTHEAST AND

TOWARD THE APPALACHIANS WITH RAIN REPLACING WINTER PRECIPITATION

FROM THE SOUTHWEST TO NORTHEAST. PREFER THE MUCH COLDER MAX

TEMPERATURES OF THE GFS FOR HIGHS MONDAY MOSTLY MID 30S TO NEAR 40.

ICING FROM ABOUT 0.1 TO 0.25 INCHES IS POSSIBLE SUNDAY NIGHT AND

MONDAY MORNING BEFORE TEMPERATURES WARM ABOVE FREEZING ESPECIALLY

SOUTHERN PLATEAU...AND EASTERN TN MOUNTAIN VALLEYS WHERE COLD AIR

BECOMES TRAPPED.

SIGNIFICANT SNOWFALL IS POSSIBLE IN THE EASTERN MOUNTAINS AND

NORTHERN TENNESSEE COUNTIES AS WELL AS SW VIRGINIA WHERE THE

ATMOSPHERIC PROFILE IS COLDER SUNDAY NIGHT AND WARMS UP LATER

MONDAY. THE SYSTEM WILL SHIFT TO THE EAST MONDAY NIGHT AND TUESDAY

AND COLDER AIR WILL GRADUALLY BE PULLED SOUTH INTO THE FORECAST

AREA. THE RAIN WILL CHANGE OVER TO A WET SNOW LATER MONDAY NIGHT

INTO TUESDAY MORNING. BY AFTERNOON TUESDAY TEMPERATURES WARM ABOVE

FREEZING TO THE 40S LOWER ELEVATIONS AND SNOW WILL CHANGE TO RAIN

EXCEPT AT HIGHER MOUNTAIN LOCATIONS WHICH SHOULD GET MORE MEASURABLE

WET SNOW.

ANOTHER QUICK MOVING SYSTEM MOVES SOUTHEAST THROUGH THE UPPER TROUGH

TUESDAY NIGHT AND WEDNESDAY. THIS KEEPS THE THREAT FOR SNOW SHOWERS

AT NIGHT AND RAIN DURING THE DAY. THE UPPER TROUGH FINALLY SHIFTS

EAST WITH UPPER LEVEL RIDGING MOVING IN THURSDAY AND FRIDAY.

TEMPERATURES WILL BE CONSIDERABLY WARMER DURING THE DAY WITH SUN

RETURNING. HIGHS THURSDAY EXPECTED TO BE IN THE MID 40S NORTH TO

UPPER 50S SOUTH...THEN 50S TO LOWER 60S FRIDAY.

Translation: We're certain that the Mountains will get hit with a lot of snow. We're uncertain when it comes to the valley.

[franklin NCwx]

I don't buy the frontal passage look. I think the trough goes negative tilt somewhere in the southeast and I just hope it's not too far west to flood us with warm air.

I think the ukie, cmc solution is how this turns out.

[Stovepipe]

Final frame of the 18z RGEM (Hour 54):

 

 

Snow:

 

Sleet:

 

Freezing Rain:

[John1122]

Best case is the Canadian/UKIE.

Then the Euro.

Then the NAM/GFS.

Even though the Euro cuts, it brings a huge front end thump for a large part of the Valley. Canadian and UKIE are self explanatory. Great miller A track that puts us all in a major snow event.

NAM spread virga, then a rush of warmth before booking it out. GFS is weak, clipperish at 18z. Would likely be an event like today then rain some.

[weathertree4u]

Best case is the Canadian/UKIE.

Then the Euro.

Then the NAM/GFS.

Even though the Euro cuts, it brings a huge front end thump for a large part of the Valley. Canadian and UKIE are self explanatory. Great miller A track that puts us all in a major snow event.

NAM spread virga, then a rush of warmth before booking it out. GFS is weak, clipperish at 18z. Would likely be an event like today then rain some.

So who wants to put out a guess as to when the modeling will come into better agreement?

[Windspeed]

It has no southern development, just ends up an amped up clipper.

Funny, the amped up upper vort max is what I was originally so excited about through the early week model runs. With it diving south and east of the Valley, that looked like a great solution for overriding a cold and dammed airmass in East Tennessee and negating any warm nose. Less of a moisture stream, but higher ratios and overall higher snow totals for East Tennessee north of I-40 and especially the I-81 corridor.

Sent from my LG G4.

[Runman292]

I think we are just about there w modelling. Expect maybe one more big shift as the feature gets sampled better(maybe it is now?). I think there are two tracks left to choose from...

1. The Euro has shown a strong disposition to cut west in an Apps runner manner.

2. Miller A track as an inland runner. Then, two options within this option, a track close to the Apps or one over the Piedmont.

I hate going agains the Euro. It is nicknamed Dr No for a reason. But right now I favor option two and a low tracking closer to the Apps which barely makes it around the corner. I also think recent snows are going to make it tough for the lower levels to be scoured. If anything (like WxSouth(?) mentioned) it might allow a meso high to build-in and hold a bit longer. This is a dynamic system. The crazier the better for me. WxSouth also mentioned the potential for thunder snow. Maybe not as fast as the NAM, but we need this to precip to break out well in front as a true overrunning event. Sometimes, this can lock-in the cold longer. And we need it to arrive overnight and the precip axis to stay flat. We have a decent shot at most of that. There will be surprises which is why this system will be interesting. The GEM is a bit too cold per Robert so I think even northern border counties will deal w some mixing. Finally qpf ahould be high in the 1-2" range and precip rates may keep some snow for longer if under those bands.

Carver, what are your thoughts on the 18z GFS frontal passage type scenario?

[John1122]

I'm not sure we can avoid the warn nose so we need the Euro and it's rapid expansion of major precip into the cold if we can't get the Canadian solution.

It's tough to get all snow with gulf tracks for the southern valley. It's really tough for all of us with central gulf Coast state tracks.

So hope for the biggest front end thump you can get. Also hope the heavy precip can cool from the top down. The NAM shows that happening during the event in spots. Just very heavy snow blobs on the map with the dynamic cooling.

[Carvers Gap]

I think we are just about there w modelling. Expect maybe one more big shift as the feature gets sampled better(maybe it is now?). I think there are two tracks left to choose from...

1. The Euro has shown a strong disposition to cut west in an Apps runner manner.

2. Miller A track as an inland runner. Then, two options within this option, a track close to the Apps or one over the Piedmont.

I hate going agains the Euro. It is nicknamed Dr No for a reason. But right now I favor option two and a low tracking closer to the Apps which barely makes it around the corner. I also think recent snows are going to make it tough for the lower levels to be scoured. If anything (like WxSouth(?) mentioned) it might allow a meso high to build-in and hold a bit longer. This is a dynamic system. The crazier the better for me. WxSouth also mentioned the potential for thunder snow. Maybe not as fast as the NAM, but we need this to precip to break out well in front as a true overrunning event. Sometimes, this can lock-in the cold longer. And we need it to arrive overnight and the precip axis to stay flat. We have a decent shot at most of that. There will be surprises which is why this system will be interesting. The GEM is a bit too cold per Robert so I think even northern border counties will deal w some mixing. Finally qpf ahould be high in the 1-2" range and precip rates may keep some snow for longer if under those bands.

Runman, you bailed me out, accidentally hit delete while editing. By you responding, I can copy and repost.

[Runman292]

I think we are just about there w modelling. Expect maybe one more big shift as the feature gets sampled better(maybe it is now?). I think there are two tracks left to choose from...

1. The Euro has shown a strong disposition to cut west in an Apps runner manner.

2. Miller A track as an inland runner. Then, two options within this option, a track close to the Apps or one over the Piedmont.

I hate going agains the Euro. It is nicknamed Dr No for a reason. But right now I favor option two and a low tracking closer to the Apps which barely makes it around the corner. I also think recent snows are going to make it tough for the lower levels to be scoured. If anything (like WxSouth(?) mentioned) it might allow a meso high to build-in and hold a bit longer. This is a dynamic system. The crazier the better for me. WxSouth also mentioned the potential for thunder snow. Maybe not as fast as the NAM, but we need this to precip to break out well in front as a true overrunning event. Sometimes, this can lock-in the cold longer. And we need it to arrive overnight and the precip axis to stay flat. We have a decent shot at most of that. There will be surprises which is why this system will be interesting. The GEM is a bit too cold per Robert so I think even northern border counties will deal w some mixing. Finally qpf ahould be high in the 1-2" range and precip rates may keep some snow for longer if under those bands.

Runman, you bailed me out, accidentally hit delete while editing. By you responding, I can copy and repost.

You're welcome. Can you answer my previous question?

[Carvers Gap]

Carver, what are your thoughts on the 18z GFS frontal passage type scenario?

I try not to discount things as models are truly there to give us possible options, and we choose what makes sense. Given the mountain of modeling since last Friday, only the GFS has tried this early on. I really like a blend of the GFS and Euro which would be the Canadian/Ukie solution but a bit north and west to compensate for the late jog we have seen all winter. At this point, unless other models follow...I would discount it. Last night the 18z was not good either. The 18z I usually give little weight to anyway. Others fewl free to jump-in.

Also, sorry for the typos, you all. Using an iphone which I have the auto-spell turned off. The words are small and my fingers are big... Anyway, cleaning up my posts as we go. I promise that I speak standard English. Ha!

[Runman292]

I think we are just about there w modelling. Expect maybe one more big shift as the feature gets sampled better(maybe it is now?). I think there are two tracks left to choose from...

1. The Euro has shown a strong disposition to cut west in an Apps runner manner.

2. Miller A track as an inland runner. Then, two options within this option, a track close to the Apps or one over the Piedmont.

I hate going agains the Euro. It is nicknamed Dr No for a reason. But right now I favor option two and a low tracking closer to the Apps which barely makes it around the corner. I also think recent snows are going to make it tough for the lower levels to be scoured. If anything (like WxSouth(?) mentioned) it might allow a meso high to build-in and hold a bit longer. This is a dynamic system. The crazier the better for me. WxSouth also mentioned the potential for thunder snow. Maybe not as fast as the NAM, but we need this to precip to break out well in front as a true overrunning event. Sometimes, this can lock-in the cold longer. And we need it to arrive overnight and the precip axis to stay flat. We have a decent shot at most of that. There will be surprises which is why this system will be interesting. The GEM is a bit too cold per Robert so I think even northern border counties will deal w some mixing. Finally qpf ahould be high in the 1-2" range and precip rates may keep some snow for longer if under those bands.

Runman, you bailed me out, accidentally hit delete while editing. By you responding, I can copy and repost.

Regarding the bolded, is 7 PM a good start time or is that too fast?