Absolute Vorticity

21Z SREF mean for CVG and I-70 folks... 1 to 1.5" of snow. Not bad!

winter storm watch issued for my area

It’d be isolated, but it really wouldn’t surprise me if someone in my 1-3” band hits 4”.

Overall the 00z models looked great and match my forecast very well.

Modeling does support a band of 2-4 setting up, but it will be tough to figure out just where it will be. I’m favoring either along the river or perhaps just south at the moment but want to see 12z guidance (esp high-res) to get a better idea. I’ll have an updated snowfall map later today.

Morning Trev! Every model now has the primary low stronger and getting into NE TN before dying out. We needed that to score with this system and per the data, we should get it. To counteract the marginal temps and warm ground, I still like the 1-2" maybe isolated 3". I know the data shows 2-4" but I just can't bump it up due to the temps, thermals, etc etc. If we had a bit more cold air to work with, it would be a no brainer.

At CVG - QPF for Sat:

6Z NAM - 0.32"
0Z GFS - 0.21"
0Z Euro - 0.22"

tron777 wrote: ↑Fri Jan 05, 2024 4:30 am Morning Trev! Every model now has the primary low stronger and getting into NE TN before dying out. We needed that to score with this system and per the data, we should get it. To counteract the marginal temps and warm ground, I still like the 1-2" maybe isolated 3". I know the data shows 2-4" but I just can't bump it up due to the temps, thermals, etc etc. If we had a bit more cold air to work with, it would be a no brainer.

We shall see! These systems are notorious for having some intense banding setting up. I think 4” is doable. I’m favoring that to be south/southeast of downtown.

From the boys - Terrible snow ratios too, so another reason to keep expectations in check. This stuff will have a very high water content. Concrete... literally!

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Clouds will continue to thicken and lower this evening out
ahead of the next approaching mid level s/wv. For the later part
of the night, pcpn will will increase from the west as a modest
low level jet and its associated moist ascent spread snow into
the region. With SLRs forecast to be in the 5:1 to 8:1 range,
snow amounts will generally be less than an inch. Some slick
spots may develop on untreated roadways, and especially on
bridges and overpasses as they likely drop below freezing. Will
continue to mention the snow potential in the HWO. Lows will
fall into the upper 20s north to the lower 30s south.

On Saturday, aforementioned mid level s/wv will pivot east
across the forecast area. A low level inverted trof will be
reflected at the surface with this feature. Snow north and
rain/snow south will taper off by the afternoon hours as large
scale ascent shifts east. Again, SLRs will be in the 5:1 to 8:1
range, so additional snow amounts are expected to be less than
an inch. Slick spots should improve by mid to late morning as
diurnal heating warms the air temperature and pavement
temperature as well. Highs will range from 35 degrees north to
around 40 degrees south.

Trevor wrote: ↑Fri Jan 05, 2024 4:34 am

tron777 wrote: ↑Fri Jan 05, 2024 4:30 am Morning Trev! Every model now has the primary low stronger and getting into NE TN before dying out. We needed that to score with this system and per the data, we should get it. To counteract the marginal temps and warm ground, I still like the 1-2" maybe isolated 3". I know the data shows 2-4" but I just can't bump it up due to the temps, thermals, etc etc. If we had a bit more cold air to work with, it would be a no brainer.

We shall see! These systems are notorious for having some intense banding setting up. I think 4” is doable. I’m favoring that to be south/southeast of downtown.

I like where I am sitting for this one. It'll come down hard tomorrow morning for sure and will stack up quick. I can't argue that. We'll see if enough QPF can get involved for those higher totals. If I can muster up an inch or two on the grass / car tops, I will call it a win and be pleasantly surprised should more occur.

Globals have shifted southward with the heaviest which matches up with the mesoscale models. I want to see 12z to confirm and then I will have my updated map.

Trevor wrote: ↑Fri Jan 05, 2024 4:38 am Globals have shifted southward with the heaviest which matches up with the mesoscale models. I want to see 12z to confirm and then I will have my updated map.

Sounds good man! It'll be nice watching snow fall in the morning while drinking coffee. Nothing better! I'll be back on once I get to work.

6Z GFS is similar to the 0Z run in terms of QPF for CVG.

Good Morning and finally within 24 hours of some possible snow. Les we are on the same page and 1-2 inches seems correct but I understand where Trevor is coming from because you can get an area that has a period of heavy banding and someone get 3 plus inches. Good thing is we had this shot of cold air the past 24 hours and though temps rise today this has cooled surface temps down somewhat. Having much of the precip fall before noon is a plus as well and I always mentioned the 4a-9a time period where you can enhance precip totals. What will the air temp be during when the snow is falling is key and that can be anywhere between 30-35 imo.

My final final total at CVG is 1.8 inches.

Most of the models (especially mesoscale) juiced things up on 6z. I’m feeling better about increasing my numbers a tad.

Gentlemen... It will be fun to watch tomorrow morning without a doubt. Radar is looking good over Texas this morning and you can see the Gulf getting involved as I talked about last night. Also, we have a broad 1010 MB low over the TX panhandle which is weakening as the new low just off the TX Coast at 1008 MB takes over. Nice pressure falls over LA so the low should be headed in that direction then ENE from there which is usually a good track for us for snow. This system has a nice little dig to it per 500 MB analysis. The energy has just about rounded the base of the trough so things should continue to get going to our SW as the day wears on. Over us... a 1028 MB high centered near Columbus, Ohio will slowly move off to the East as WAA begins. So far, everything looks good to me!

6Z 12KM NAM is really the best case scenario. It has a weenie 3"+ band over NKY as the primary lasts longer thru TN and into WVA before finally giving it up to the EC Low. Folks... the longer the primary can last, the more snow we will receive. Definitely something to watch on the 12z guidance today. The 3KM NAM is doing the same thing, but has the weenie band for our SE Crew. 4"+ wow!

Even the WRF looks good for us! As Trev mentioned... the mesoscale / hi res guidance is really going all in with this thing. I can't find a single model that looks terrible to be honest. I may need to join the Trev camp if the 12Z runs confirm.

tron777 wrote: ↑Fri Jan 05, 2024 6:25 am 6Z 12KM NAM is really the best case scenario. It has a weenie 3"+ band over NKY as the primary lasts longer thru TN and into WVA before finally giving it up to the EC Low. Folks... the longer the primary can last, the more snow we will receive. Definitely something to watch on the 12z guidance today. The 3KM NAM is doing the same thing, but has the weenie band for our SE Crew. 4"+ wow!

Good morning Les and with all storms there are always surprises when dealing with snow both high and low. My plan is to get up around 4am which is pretty close to normal anymore and hopefully several hours of snow. Like I mentioned this is the appetizer of upcoming events including next Tuesday/Wednesday which I believe more folks in the weather world will start talking about more and more over the next few days

tpweather wrote: ↑Fri Jan 05, 2024 6:31 am

tron777 wrote: ↑Fri Jan 05, 2024 6:25 am 6Z 12KM NAM is really the best case scenario. It has a weenie 3"+ band over NKY as the primary lasts longer thru TN and into WVA before finally giving it up to the EC Low. Folks... the longer the primary can last, the more snow we will receive. Definitely something to watch on the 12z guidance today. The 3KM NAM is doing the same thing, but has the weenie band for our SE Crew. 4"+ wow!

Good morning Les and with all storms there are always surprises when dealing with snow both high and low. My plan is to get up around 4am which is pretty close to normal anymore and hopefully several hours of snow. Like I mentioned this is the appetizer of upcoming events including next Tuesday/Wednesday which I believe more folks in the weather world will start talking about more and more over the next few days

Good morning Tim! Strongly agree.... we are absolutely on the same page here 100%.

3Z SREF showing 0.40"+ on the mean for QPF. It's been fairly juicy over the last few runs. However, the snow mean is very low. IMO I do not think that the SREF is handling the dynamic cooling processes correctly. If it was, we'd be seeing a 2-3" snowfall mean instead of 3/4".

Looking down to our SW and there is a winter weather advisory issued for the Ozarks in NW ARK for 1-3" of snow effective until noon central time today. Always a good sign when you see an advisory issued down that way. I would expect additional WWA's to be issued this afternoon.

tron777 wrote: ↑Fri Jan 05, 2024 7:00 am Looking down to our SW and there is a winter weather advisory issued for the Ozarks in NW ARK for 1-3" of snow effective until noon central time today. Always a good sign when you see an advisory issued down that way. I would expect additional WWA's to be issued this afternoon.

Yes and did expand those somewhat this morning which is also a good sign

These forecasted snowfall maps by the NWS seem to always be wrong. Most of the time, very wrong. This map has the heaviest accumulation to the north of and along I-70. Very little in northern Kentucky. No model is showing this. What is the thought process? Are these maps from ILN or do they originate on a national scale?

dce wrote: ↑Fri Jan 05, 2024 8:01 am These forecasted snowfall maps by the NWS seem to always be wrong. Most of the time, very wrong. This map has the heaviest accumulation to the north of and along I-70. Very little in northern Kentucky. No model is showing this. What is the thought process? Are these maps from ILN or do they originate on a national scale?

I have no ideal Doug. Looks like they believe the system on Saturday is mainly rain and then they expect folks further north to get some snow on Sunday. I agree about the system on Sunday but disagree about Saturday.

tpweather wrote: ↑Fri Jan 05, 2024 8:04 am

dce wrote: ↑Fri Jan 05, 2024 8:01 am These forecasted snowfall maps by the NWS seem to always be wrong. Most of the time, very wrong. This map has the heaviest accumulation to the north of and along I-70. Very little in northern Kentucky. No model is showing this. What is the thought process? Are these maps from ILN or do they originate on a national scale?

I have no ideal Doug. Looks like they believe the system on Saturday is mainly rain and then they expect folks further north to get some snow on Sunday. I agree about the system on Sunday but disagree about Saturday.

I don't know the answer either but my guess would be computer generated graphics with very little human analysis.