Arctic Front/Lakes Fetch Snow Dec 20-23

Late next week into the weekend a powerful Arctic cold front will blast through the eastern US bringing the coldest temps of the season to the eastern half of the country! Due to how deep the parent low will become it will allow for a VERY strong cold advection fetch from the Great lakes.

Heavy lake effect snow bands will overtake spots around the great lakes that are accustom to lake effect events and the Appalchian mountains will experience a notable upslope event with snow squalls even into the lower elevations. Due to how cold this airmass will be I expect light accumulations even in unelevated spots especially west of the mountains in the OH and upper TN valleys.

More northward light accumulations will also be possible east of the mountains but these accums should drop off the along the coast where it will mostly be just a heavy rain event ending in snow showers.

Its pretty much a given that there will be a substancial upslope event across the plateau and mountains. Its also my personal opinion that there will be light accumulations in unelevated spots in northern areas of middle and east TN too.

0z EURO



It also wouldn't surprise me to see the cold even catch up to the back end of the precip associated with the front itself. I dont see much of a severe threat ahead of the cold front due to the warm sector being rather unimpressive but severe cannot be ruled out

I hope you all cash in on this storm system toot, because Lawrenceburg does not fare to well with these storm systems lol.

12zGFS is suffereing from its east cold bias

12zCMC's take on the Arctic Front and fetch

And would you look at that huge ridge out west?

Adam2014 wrote:I hope you all cash in on this storm system toot, because Lawrenceburg does not fare to well with these storm systems lol.

I'm not sure I do well either Adam, so I feel your pain. Although all I have to go on is the "non" winter of last year. If the precip could somehow catch the cold air as Toot said earlier, i'd feel better about it. I'll also feel better about it if the EC shows the same as the canadian here in a min.

Jed33 wrote:

I'm not sure I do well either Adam, so I feel your pain. Although all I have to go on is the "non" winter of last year. If the precip could somehow catch the cold air as Toot said earlier, i'd feel better about it. I'll also feel better about it if the EC shows the same as the canadian here in a min.

Jet last fall/winter was a super positive AO while this one has been a complete opposite..so that wouldnt be a good winter to compare this one to
That said..actually Hamblen county has done fairly well with the stronger cold advected NW Flow events..especially in 09/10 and 10/11.This is due to nooks and crannies in the northern plateau which reduces downsloping in Morristown during NW flow events

This system looks alot like an event we called "The Bluegrass runner" back in 2010/11 on the other forum were several spots ended up with six inches of NW flow snowsqualls thanks to lagging upper level vorticity.

As of now I expect light accums in the Morristown area with a slighter possibility of a 2-4 inches. I will fine tune my thoughts as we get a little closer

Awesome Toot! Here's to hoping it makes it to the level that the "Bluegrass runner" did back then. I remember that one, you guys did well over here, while I was left high and dry in S Mid TN. Although, we still did well that year, and we even had a little lake effect over there.
On another note, did the Euro stay consistent, or did it cave to the gfs. I can't find a solid opinion from the other boards, lol.

Edit: Ok, I see now that it appears that it stayed fairly consistent.

Nashville, that I can remember, rarely gets much accumulating snows out of this type of set-up but it does make for a nice winters day with on and off snow showers (sometimes quite heavy..enough to coat the grass before the sun melts it off between snow showers).

In reference to the colder pattern the euro held serve.. they're minor differences in west and east trough/ridge placement (Trough east/Ridge west). Just notice the PNA ridging/slpit flow pattern is contiuing to be progged.

Thats what we have excellent agreement on in all guidance

All posts associated with the arctic front should go in this thread and not in the winter discussion thread. This will keep everything more organized as the wx gets more active.

Yesir that is one impressive looking cold advection fetch if ive ever seen one on the 0zGFS



Wouldnt surprise me if we seen snow deep down into GA/AL with such a deep and vigorous low like that in such vicinity of the lakes. I wouldnt pay attention to QPF in an event like this because its purely snow squalls which pulse up and down but are very plentiful

Nice pic Toot. LOL. Wonder how long it takes to get the fetch going? This is going to be a pretty quick in and out deal (taking gfs verbatim).

snowdog wrote:Nice pic Toot. LOL. Wonder how long it takes to get the fetch going? This is going to be a pretty quick in and out deal (taking gfs verbatim).

Looks like it starts late thursday and lasts through the weekend in east TN .of course the precip will start to taper off from middle tennesse by late friday/early Saturday. I beleive even southern locations may be in play as well. This is the strongest fetch ive seen modeled in a few years

The last one I remember here was 2 or 3 Decembers ago. Can't remember which, I've had another kid since then. LOL.

That was in the 2010/11 winter..fetched snow all the way doen to the FL line

Just to give somebody who might not understand the 850mb map above and idea what were talking about.. Here is how far south the GFS is says snow will snow fall

Nice!

12z CMC EXTREME fetch...this one looks like fun folks!!

MRX early this morning

THE NEXT UPPER TROUGH AND SURFACE COLD FRONTAL SYSTEM WILL BE KNOCKING ON THE DOOR LATER WEDNESDAY NIGHT. MODELS CONTINUE TO SHOW A RATHER AMPLIFIED HEIGHT PATTERN WITH THIS SYSTEM AND EVEN THOUGH THE EVENT IS ON DAY 5...THE STRENGTH OF THIS FEATURE AND MODEL AGREEMENT PUSH PROBABILITY OF PRECIP TO THE LIKELY CATEGORY. STRONG COLD AIR ADVECTION (85H TEMPS AROUND -5 TO -10 C) AND SUFFICIENTLY DEEP MOISTURE ALONG WITH A NICE UPSLOPE COMPONENTSHOULD ALLOW FOR THE DEVELOPMENT OF SNOW SHOWERS

JKL just to MRX's north

THIS WEATHER SYSTEM WILL DRAW A LARGE AREA OF COLD CANADIAN AIR DOWN INTO THE CENTRAL CONUS AS IT MOVES EAST...WHICH WILL AID IN THE FORMATION OF A VERY WELL DEFINED COLD FRONT. WIDESPREAD LIGHT TO MODERATE RAIN SHOWERS WILL FORM ALONG AND AHEAD OF THE FRONT...MAKING FOR A GOOD SOAKING RAIN EVENT AS THE BOUNDARY MOVES ACROSS THE OHIO AND TENNESSEE VALLEYS. AS THE COLD AIR FILTERS INTO THE AREA BEHIND THE DEPARTING FRONT THURSDAY NIGHT AND EARLY FRIDAY...RAIN WILL MIX WITH AND CHANGE OVER TO ALL SNOW. HOWEVER...WITH THE DEPTH OF THE MOISTURE IN THE COLD AIR BEING FAIRLY SHALLOW...AND WITH MUCH LESS THAN IDEAL WESTERLY FLOW BEHIND THE FRONT...THE SNOW WILL BE LIGHT AT BEST...WITH ONLY VERY LIGHT ACCUMULATIONS POSSIBLE ON MAINLY GRASSY AREAS AND RIDGETOPS. ONCE THIS FINAL BIT OF PRECIPITATION PUSHES OUT OF THE AREA EARLY ON FRIDAY...ANOTHER AREA OF COLD HIGH PRESSURE WILL SETTLE OVER THE AREA THROUGH THE UPCOMING WEEKEND.

WITH A GOOD FETCH OF GULF MOISTURE RIDING MOISTURE ON SOUTHERLY WINDS TO BEGIN THE PERIOD...DAY TIME HIGHS WILL BE THE 50S TUESDAY THROUGH THURSDAY. TEMPERATURES ON FRIDAY WILL BE MUCH COLDER...AS THE COLD FRONT PASSES BY...AND HIGHS BY FRIDAY AFTERNOON WILL LIKELY ONLY MAKE IT INTO THE UPPER 30S TO PERHAPS 40 IN A FEW OF OUR SOUTHERN COUNTIES. THE WEEKEND WILL SEE A SLIGHT WARM UP AS THE AIR MASS GRADUALLY MODIFIES...WITH HIGHS IN THE 40S ON TAP.

MRX mentioning accumulations already..what the heck has gotten into them? lol

SURFACE LOW DEEPENS OVER MID MS VALLEY THURSDAY AND RAPIDLY MOVES NE INTO THE EASTERN GREAT LAKES FRIDAY. SHOWERS BECOME LIKELY THURSDAY. MUCH COLDER AIRMASS BEHIND COLD FRONT THURSDAY NIGHT TO CHANGE PRECIPITATION TO SNOW SHOWERS BEFORE ENDING OVERNIGHT VALLEYS AND FRIDAY NORTHEAST AND EASTERN MOUNTAINS. AMOUNTS IN THE MOUNTAINS COULD BE A COUPLE OF INCHES BUT IN THE VALLEY AREAS TOO EARLY TO TELL IF ANY COULD ACCUMULATE BEFORE MOISTURE MOVES OUT AND IF TEMPERATURES GET COLD ENOUGH FOR SNOW TO STICK BEFORE ENDING. HIGHS FRIDAY ONLY EXPECTED TO REACH THE LOWER 30S HIGHER ELEVATIONS AND PARTS OF THE NE WITH LOWER TO MID 40S ELSEWHERE. FRIDAY NIGHT LOWS IN THE 20S.

00z GFS has a 980 low over the lakes

SEMonroeWx wrote:00z GFS has a 980 low over the lakes

great point monroe... this thing is starting to get modeled even stronger... i will be posting more on this in the severe section

The CMC was the first model to pick up on this system as I have found it is good at keying in on big storm systems in the extended long before other models do. Its not as accurate after the fact tho..but anyways it has been very consistent with the extreme fetch. The GFS/EURO are not as extreme but have been in previous runs. Either way it looks like the majority of people will see their first flakes with this system. Maybe even some light accumulations if the consistent outcome the canadian shows verifies

MRX seems to suggest possible accums only in the higher elevations which seems to be the correct call for now. I do think this system will overperform especially on the plateau but it wouldnt surprise me to see a quick dusting in some of the northern valley locales too.

Here is an interesting AFD from the eastern KY office JKL

Code:

A SIGNIFICANT STORM SYSTEM TAKING SHAPE OVER THE SOUTH CENTRAL
CONUS. IT WILL BECOME VERY INTENSE AS IT MOVES RAPIDLY NORTHEAST
OVER THE GREAT LAKES. ITS COLD FRONT SHOULD PASS THROUGH FROM WEST
TO EAST ON THURSDAY. SHOWERS ARE EXPECTED ALONG AND AHEAD OF THE
FRONT...WITH ENOUGH INSTABILITY ALSO PRESENT FOR A RISK OF THUNDER.
A MUCH COLDER AIR MASS ARRIVES BEHIND THE FRONT...WITH A POSSIBILITY
OF SNOW OVER EASTERN KENTUCKY THURSDAY NIGHT INTO FRIDAY. THIS WOULD
BE DUE TO A COMBINATION OF THE SOUTHERN EDGE OF THE COMMA HEAD UNDER
THE UPPER TROUGH AXIS PASSING OVER DURING PERSISTENT COLD UPSLOPE
FLOW. WILL STICK WITH 20-30 PERCENT POPS AT THIS POINT...WITH ANY
PRECIP AMOUNTS BEING LIGHT. THE LARGE STORM SYSTEM SHIFTS FURTHER
EAST ON FRIDAY...LEAVING DRY BUT STILL COLD CONDITIONS.