Absolute Vorticity

We'll use this thread to discuss the wave coming up for Wed evening along the arctic front. Central and Eastern KY are favored for highest totals. CVG Land has a shot at an inch or two and we are trying to see how far north this is going to go to get more people involved. Currently a south of I-70 event.

6Z GEFS Mean, it and the OP GFS have taken over as the most north solutions followed by the NAM. 6Z RGEM has come north to now clip CVG with a bit of snow for the first time. CMC is S / SE Crew only. UKIE clips CVG. Euro misses everyone still. Have not seen the EPS.

From the boys:

Disturbance over the southern plains Tuesday night will begin
to lift northeast toward the Tennessee Valley on Wednesday. At
the same time, a cold front will drop southeast from the Great
Lakes. Current guidance shows little precipitation associated
with the front; however, rain will spread into the Tri-state
region ahead of the southerly disturbance late in the period.
Temperatures on Tuesday night will likely stay steady in the mid
30s to around 40, then lift into lower 40s on Wednesday ahead
of the front. Current timing of the front suggests temperatures
will fall back into the 30s from northwest to southeast
Wednesday afternoon behind the front.

The cold front will be just south of our area by Wednesday
evening. However, the 00Z models have trended a little farther
north with a wave riding along the frontal boundary Wednesday night
and the associated frontogenetic forcing. As cooler air moves in
behind the front, ptype will transition over to snow from the
northwest through the evening hours. This will lead to a period of
snow across southern portions of our area before the pcpn tapers
off later Wednesday night. As a result some light accumulations
will be possible across about the southeast third of our fa.
The 00Z GFS and NAM are farther north than the ECMWF with the
accumulating snow with the 00Z GFS ensemble mean suggesting the
possibility of a few inches of snow across our far southeast. For
now will take more of a blend of the GFS and ECMWF ensemble means
and generally keep accumulations at an inch or less.

6Z GEFS Mean:

CB's early call map is out for his weenies:

Good Morning Les. Glad you made a thread for this system. Again not a big snow by any means but to me maybe the biggest problem is the cold coming in fast after a dose of rain which can end up having a flash freeze which is the worse possible outcome. Matter of fact a little snow would help somewhat in that department as you would have a little traction. Gives us something to watch over the next 36 hours or so.

Good morning Tim... thanks! Bgoney's positive post this morning in the other thread was the first thing I saw before I even looked at a model. After I looked at a few, I decided to give it a go.

We need the trough to sharpen up and amplify a little more to get the better totals in here. However, there is only so much room at can come north with a monster 1045-1050 MB high dropping in from the NW. It will push down on the snow shield as the dry, arctic air tries to take over. How much overrunning or anafrontal snow can we see behind the front? Today's data ought to be really interesting to see if we can begin to nail that down a little more.

Good Morning Les. Another thing is the ratios will go up quickly because of the cold air moving in so you get up to 15-1 very quickly so .10 gives you inch and half or so of snow.

tpweather wrote: ↑Tue Jan 18, 2022 7:50 am Good Morning Les. Another thing is the ratios will go up quickly because of the cold air moving in so you get up to 15-1 very quickly so .10 gives you inch and half or so of snow.

This is dense arctic air so getting the cold to press in here isn't a problem. How much QPF can we get is the issue. I'd take a few hundredths off the top of any model data QPF that is posted since it is still to me looking like a rain quickly changing to snow event Wed afternoon and evening. Going to be close to see if the snow starts during the PM commute or not.

I thought we might get a separate event thread. Right on the edge for many as usual. But CB to the rescue!!

What I would like to see is no rain at all on Wednesday. Yes we will still have some snow melt so some roads will still be wet. I am more worried about the flash freeze and that is greater if we see rain on Wednesday. This is a nice shot of cold and being dense it will no doubt works its way to the ground very quickly. Some cold air masses are not as dense and it takes a little time for the really cold air to hit the ground but this cold air mass is dense so that worries me somewhat. I would like to see just enough snow to at least have some traction. I seen this situation so many times and depending when it hits the traffic becomes a stand still especially at rush hour times.

9Z SREF Mean

CVG - 1.3"
HAO - 1"
DAY - 0.6"
CMH - 1"

LOU - 1.8"
LEX - 2.6"

At CVG, the model has light rain coming in around 2-3pm changing to snow around 5-6pm.

BG SnowTalk! https://www.wave3.com/2022/01/18/snowta ... pdate-118/

So close for CVG... we get clipped. Looking good for our S counties / SE crew though as has been the case with this pattern to date.

tron777 wrote: ↑Tue Jan 18, 2022 9:23 am

Code: Select all

FGX 

WED  1P 19-JAN   2.9     1.8    1018     100      65    0.02     558     543    
WED  7P 19-JAN   2.5     1.3    1018      99      98    0.07     557     542    
THU  1A 20-JAN  -2.3    -3.3    1022      94      97    0.62     554     537    
THU  7A 20-JAN  -7.6    -9.1    1029      84      42    0.02     553     531 

Not a bad start!

BookNerdCarp wrote: ↑Tue Jan 18, 2022 9:27 am

tron777 wrote: ↑Tue Jan 18, 2022 9:23 am

Code: Select all

FGX 

WED  1P 19-JAN   2.9     1.8    1018     100      65    0.02     558     543    
WED  7P 19-JAN   2.5     1.3    1018      99      98    0.07     557     542    
THU  1A 20-JAN  -2.3    -3.3    1022      94      97    0.62     554     537    
THU  7A 20-JAN  -7.6    -9.1    1029      84      42    0.02     553     531 

Not a bad start!

I'd take some of that off for rain /. snow melting purposes but still a nice event shaping up down your way for a couple of inches easy.

12Z RGEM:

BG's thinking was a lot further south.

What makes these systems bad is when it snows at first a wet snow and then the colder air comes in and turns it into a more power like snow. So when you shovel you get the powder off but you have the ice that has formed underneath. These kind of events travel wise are worse imo than a bigger snow. My son text me and mentioned the side roads have not even been touched down there as of this morning. They got over half a foot and I never thought about a snow shovel but there is not one at the house and my son looked at the hardware stores and none to be found.

We were out of school today - All of Brown County is out. Back roads here are still rough. Should be better with melting today. Then rinse and repeat tomorrow night.

Yesterday afternoon I was bringing the garbage cans up the driveway and it was a sheet of ice. Mid-January solar radiation is just not that great so hard to melt the pavements even the ones facing south.

tpweather wrote: ↑Tue Jan 18, 2022 10:16 am What makes these systems bad is when it snows at first a wet snow and then the colder air comes in and turns it into a more power like snow. So when you shovel you get the powder off but you have the ice that has formed underneath. These kind of events travel wise are worse imo than a bigger snow. My son text me and mentioned the side roads have not even been touched down there as of this morning. They got over half a foot and I never thought about a snow shovel but there is not one at the house and my son looked at the hardware stores and none to be found.

Isn't it supposed to snow down there again late week?

12Z GFS coming in about the same as it has been. It continues to be the furthest north to give the Tri-state area the best chance among models.

Bgoney wrote: ↑Tue Jan 18, 2022 10:53 am

tpweather wrote: ↑Tue Jan 18, 2022 10:16 am What makes these systems bad is when it snows at first a wet snow and then the colder air comes in and turns it into a more power like snow. So when you shovel you get the powder off but you have the ice that has formed underneath. These kind of events travel wise are worse imo than a bigger snow. My son text me and mentioned the side roads have not even been touched down there as of this morning. They got over half a foot and I never thought about a snow shovel but there is not one at the house and my son looked at the hardware stores and none to be found.

Isn't it supposed to snow down there again late week?

Looks like maybe some ice on Friday and the weekend is a maybe but the chances are no doubt there. Very little snow removal equipment down there and hardware stores do not keep a lot of shovels around because this is the 3rd year since I have been there and this was the first time to use a snow shovel plus with supply shortages across the country my guess getting any in this season is not likely