Absolute Vorticity

Love it!

just remember whatever you do get its not going anywhere with that arctic hammer coming down next week. if you dont go out and clean it right away you are going to have a slippery frozen mess for a long time to come

airwolf76 wrote: ↑Thu Jan 02, 2025 1:40 pm just remember whatever you do get its not going anywhere with that arctic hammer coming down next week. if you dont go out and clean it right away you are going to have a slippery frozen mess for a long time to come

Exactly, which is why no one wants sleet or frz rain. Much easier to deal with just plain snow. Unfortunately though in our area, it's tough since we usually have to deal with precip type issues.

fyrfyter wrote: ↑Thu Jan 02, 2025 1:10 pm Ice accretion creeping into the area- so at least .10” I’ll keep my 4-6” right now, and throw in the ice.


IMG_0901.jpeg

Holy cow. Half an inch of iccretion. That is not good at all.

What a mess. Of course I want all snow, but a snow/sleet or frz rain/snow sandwich does NOT sound like fun. It does look northern KY might get above freezing for a few hours, so a snow / rain-melt-freeze / snow sounds even worse. Of note the euro has the freeze line much further south than the GFS.

tron777 wrote: ↑Thu Jan 02, 2025 1:06 pm Here's the 12z Euro text data for CVG:

Code: Select all

SUN 18Z 05-JAN  -4.1    -4.2    1024      53     100    0.03     558     540    
MON 00Z 06-JAN  -5.1    -2.7    1017      90     100    0.37     556     543    
MON 06Z 06-JAN  -4.3    -1.3    1009      92      92    0.55     548     541    
MON 12Z 06-JAN  -5.1    -4.7    1007      88      90    0.30     540     535    
MON 18Z 06-JAN  -3.7    -9.3    1013      83      92    0.19     540     529 

Taking the data at face value, we start as snow, but look at the last column. That number creeps above 540 so I would say some sleet occurs in there. The second column of numbers is 850 temps and it does stay below zero so at CVG, if this is correct, the frz rain would stay to our south. Then, we get more snow of course once the mid levels cool back down. So if we add up the QPF, we get a total of 1.44" and out of that, IMO about half of it would fall as sleet. So taking the Euro at face value, I'd go with 6-8" of snow at CVG and some sleet too. I'd go with 10-15" if it were all snow mind you.

Where do you find the text data for different locations?

MJSun wrote: ↑Thu Jan 02, 2025 11:57 am

Snow43130 wrote: ↑Wed Jan 01, 2025 8:24 pm My daughter is getting married that day .

Congratulations!!!

Thank you we are preparing to be dressed extremely warm to go outside and get pictures in the 16 degree temps, the snow will be pretty in the pictures .

mainevilleweather wrote: ↑Thu Jan 02, 2025 2:47 pm

tron777 wrote: ↑Thu Jan 02, 2025 1:06 pm Here's the 12z Euro text data for CVG:

Code: Select all

SUN 18Z 05-JAN  -4.1    -4.2    1024      53     100    0.03     558     540    
MON 00Z 06-JAN  -5.1    -2.7    1017      90     100    0.37     556     543    
MON 06Z 06-JAN  -4.3    -1.3    1009      92      92    0.55     548     541    
MON 12Z 06-JAN  -5.1    -4.7    1007      88      90    0.30     540     535    
MON 18Z 06-JAN  -3.7    -9.3    1013      83      92    0.19     540     529 

Taking the data at face value, we start as snow, but look at the last column. That number creeps above 540 so I would say some sleet occurs in there. The second column of numbers is 850 temps and it does stay below zero so at CVG, if this is correct, the frz rain would stay to our south. Then, we get more snow of course once the mid levels cool back down. So if we add up the QPF, we get a total of 1.44" and out of that, IMO about half of it would fall as sleet. So taking the Euro at face value, I'd go with 6-8" of snow at CVG and some sleet too. I'd go with 10-15" if it were all snow mind you.

Where do you find the text data for different locations?

It used to be you had to subscribe for it. I’m not sure it’s publicly available for free.

allowat3 wrote: ↑Thu Jan 02, 2025 1:01 pm Where I live, it looks like we are going to get a lot of freezing rain between the initial snow and back end snow. Time to get the ice chopper and pain killers ready.

Be careful with chopping any ice accretion, my Mom sustained an umbilical hernia in the mid-late 1980s when my folks and I resided in NY state from having chopped some ice with a hoe on our driveway. Thankfully she had a successful hernia repair and has been doing well re that over the years.

Let's get this party started as both Indy and Louisville NWS offices have put out winter storm watches already. You don't that happens to often just less than 3 days away

tpweather wrote: ↑Thu Jan 02, 2025 3:25 pm Let's get this party started as both Indy and Louisville NWS offices have put out winter storm watches already. You don't that happens to often just less than 3 days away

I was thinking ours would go up overnight.

BookNerdCarp wrote: ↑Thu Jan 02, 2025 3:30 pm

tpweather wrote: ↑Thu Jan 02, 2025 3:25 pm Let's get this party started as both Indy and Louisville NWS offices have put out winter storm watches already. You don't that happens to often just less than 3 days away

I was thinking ours would go up overnight.

Great Post and I agree since we are further east. The Paducah office has also posted watches for some of their area as well

18z NAM brings the Low into NKY and causes us to have the other problem - dry slot, which kills our accumulation.

fyrfyter wrote: ↑Thu Jan 02, 2025 3:43 pm 18z NAM brings the Low into NKY and causes us to have the other problem - dry slot, which kills our accumulation.


IMG_0903.jpeg

Yes the NAM loves to bring the warm air advection with these systems and many times that is correct. If this storm really gets stronger then no doubt that can happen but at this moment I believe the dry slot will stay in south of Lexington. Will watch this though once the storm is getting into our area.

Looking at the models more than ever for me and wanted to see what the NAM showed and yes like I mentioned the other day if the low gets to Owensboro,Ky like this model shows then yes we need to worry somewhat. But even the Nam stops the northward progression and then pushes the low straight east and the back end snows on this system are nice as well. 25 miles can make a big difference with this storm.

All the models have trended the low a bit further north today, so not surprising the NAM is following

Keep up the good work folks. Heading out soon and playing a few hands of euchre. Need to pay for Christmas lol.

fyrfyter wrote: ↑Thu Jan 02, 2025 3:08 pm

mainevilleweather wrote: ↑Thu Jan 02, 2025 2:47 pm

tron777 wrote: ↑Thu Jan 02, 2025 1:06 pm Here's the 12z Euro text data for CVG:

Code: Select all

SUN 18Z 05-JAN  -4.1    -4.2    1024      53     100    0.03     558     540    
MON 00Z 06-JAN  -5.1    -2.7    1017      90     100    0.37     556     543    
MON 06Z 06-JAN  -4.3    -1.3    1009      92      92    0.55     548     541    
MON 12Z 06-JAN  -5.1    -4.7    1007      88      90    0.30     540     535    
MON 18Z 06-JAN  -3.7    -9.3    1013      83      92    0.19     540     529 

Taking the data at face value, we start as snow, but look at the last column. That number creeps above 540 so I would say some sleet occurs in there. The second column of numbers is 850 temps and it does stay below zero so at CVG, if this is correct, the frz rain would stay to our south. Then, we get more snow of course once the mid levels cool back down. So if we add up the QPF, we get a total of 1.44" and out of that, IMO about half of it would fall as sleet. So taking the Euro at face value, I'd go with 6-8" of snow at CVG and some sleet too. I'd go with 10-15" if it were all snow mind you.

Where do you find the text data for different locations?

It used to be you had to subscribe for it. I’m not sure it’s publicly available for free.

For us Non Mets, as far as I know, only Accuwx Pro has it and it's pay of course.

tpweather wrote: ↑Thu Jan 02, 2025 3:25 pm Let's get this party started as both Indy and Louisville NWS offices have put out winter storm watches already. You don't that happens to often just less than 3 days away

Confidence must be at an all time high! I only recall this happening like one other time.

The northward trend is alive and well. How far north will it go? Due to the blocking and confluence it can only go so far north. Also, notice on the 18Z NAM. The low is above 1000 MB so not terribly strong. So why so far north? A lobe of vorticity in S Canada was acting like a blocker putting the squeeze play and causing the low to shear out as it headed east and also once it ran into the brick wall, it could not come north. The low had to come east. Why the changes? That lobe of vorticity in Canada is there but further to the East. It's not pressing up against the trough. So the confluence over New England is weaker and the low is able to track more northward even though it is not terribly strong.

Here is the 18Z GFS from 12/31. See where the PV is? I circled it for you. The low tracks thru middle TN and we get all snow at CVG. Really everyone does.


Now, look at the 12Z GFS from today. See the difference in where the red circled area is? It can be the little things like this, that the models got wrong several days ago and as we get closer in time, they are getting the features more correct in terms of placement and location. Thus, the entire outcome of the storm is changed.


The next 24 hours should tell us the rest of the story. I can see why the NAM came north like everyone else but I think it is overdone. It should correct back to the south a touch in future runs (unless it's right obviously).

18zgfs gives a nice amount of snow and some sleet and freezing rain

18z GFS is awful. We get some snow, but we also get clobbered with ice.

Gfs 18z 540 thickness line is now up to Cbus

ILN Risk Map:

This is going to be a large impactful storm! It can still shift south and could still go north. Looking forward to the other model runs.