Absolute Vorticity

tron777 wrote: ↑Mon Jan 01, 2024 5:20 pm 18Z GFS came back north with the primary into WVA. Heaviest snows SE of our local area as you would expect.

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CVG

SUN 00Z 07-JAN   0.6    -3.0    1010      98      95    0.15     546     538    
SUN 06Z 07-JAN  -0.1    -3.1    1010      97      93    0.06     544     536    
SUN 12Z 07-JAN  -1.7    -4.7    1013      94      95    0.01     543     532    

HAO

SUN 00Z 07-JAN   0.2    -3.1    1011      98      95    0.14     546     537    
SUN 06Z 07-JAN  -0.7    -3.5    1010      97      97    0.08     544     535    
SUN 12Z 07-JAN  -2.2    -5.2    1013      96      92    0.01     542     532    
SUN 18Z 07-JAN   1.6    -5.3    1016      82      59    0.01     544     532   

MGY

SUN 00Z 07-JAN  -0.1    -3.1    1011      97      95    0.11     546     537    
SUN 06Z 07-JAN  -1.3    -3.5    1010      97      97    0.13     543     535    
SUN 12Z 07-JAN  -2.8    -5.3    1013      98      90    0.04     542     532    
SUN 18Z 07-JAN   0.7    -5.7    1016      86      68    0.01     543     531 

DAY

SUN 00Z 07-JAN  -0.3    -3.4    1012      96      95    0.05     546     537    
SUN 06Z 07-JAN  -1.6    -3.9    1011      97      97    0.14     543     534    
SUN 12Z 07-JAN  -2.5    -5.5    1013      98      92    0.06     541     531    
SUN 18Z 07-JAN   0.3    -6.0    1016      88      74    0.01     543     530    

CMH

SUN 00Z 07-JAN   0.3    -3.0    1012      86      96    0.02     547     538    
SUN 06Z 07-JAN  -0.5    -2.5    1009      97      97    0.18     543     536    
SUN 12Z 07-JAN  -1.5    -6.1    1011      98      99    0.17     542     533    
SUN 18Z 07-JAN   0.5    -6.4    1014      92      80    0.02     542     531    

FGX

SUN 00Z 07-JAN   0.1    -1.8    1008      99      97    0.36     547     540    
SUN 06Z 07-JAN   0.1    -2.6    1008      99      88    0.37     545     538    
SUN 12Z 07-JAN  -1.3    -4.4    1012      98      81    0.02     544     534    

I like seeing this. 18z gfs always has credibility even more so than any other run a lot of times. Usually in this setup the transfer happens north of what is forecasted too. So this is looking really good imo. A lot of times the transfer happens near the Ohio West Virginia border which usually mixes some graupel freezing rain in my area. Regardless of the outcome at least this gives us something to look at for the week!

For fun... here are the CIPS Analog, centered on Jan 7th. #1 Analog is Feb 5-6th 2010 Also nice to see 1994 and 1996 on the list as well.

Phr0z3n wrote: ↑Mon Jan 01, 2024 5:34 pm I like seeing this. 18z gfs always has credibility even more so than any other run a lot of times. Usually in this setup the transfer happens north of what is forecasted too. So this is looking really good imo. A lot of times the transfer happens near the Ohio West Virginia border which usually mixes some graupel freezing rain in my area. Regardless of the outcome at least this gives us something to look at for the week!

Yeah... I like where we sit attm too. If we get that last minute NW bump, we can definitely afford it without running the risk of mixing. The overall pattern is loaded. This won't be the only threat IMO. The next few weeks should be fun!

tron777 wrote: ↑Mon Jan 01, 2024 5:43 pm

Phr0z3n wrote: ↑Mon Jan 01, 2024 5:34 pm I like seeing this. 18z gfs always has credibility even more so than any other run a lot of times. Usually in this setup the transfer happens north of what is forecasted too. So this is looking really good imo. A lot of times the transfer happens near the Ohio West Virginia border which usually mixes some graupel freezing rain in my area. Regardless of the outcome at least this gives us something to look at for the week!

Yeah... I like where we sit attm too. If we get that last minute NW bump, we can definitely afford it without running the risk of mixing. The overall pattern is loaded. This won't be the only threat IMO. The next few weeks should be fun!

Yep absolutely! Too bad that monster after this one is a lakes cutter.

18Z GEFS looks really good! Perfect track on the mean... from Middle TN thru the sweet spot of E KY / SE OH / WV border area as it slowly transfers to the EC Low.

Phr0z3n wrote: ↑Mon Jan 01, 2024 5:48 pm

tron777 wrote: ↑Mon Jan 01, 2024 5:43 pm

Phr0z3n wrote: ↑Mon Jan 01, 2024 5:34 pm I like seeing this. 18z gfs always has credibility even more so than any other run a lot of times. Usually in this setup the transfer happens north of what is forecasted too. So this is looking really good imo. A lot of times the transfer happens near the Ohio West Virginia border which usually mixes some graupel freezing rain in my area. Regardless of the outcome at least this gives us something to look at for the week!

Yeah... I like where we sit attm too. If we get that last minute NW bump, we can definitely afford it without running the risk of mixing. The overall pattern is loaded. This won't be the only threat IMO. The next few weeks should be fun!

Yep absolutely! Too bad that monster after this one is a lakes cutter.

No doubt! It will wipe out whatever we do see this weekend. But the good news is... we will rebuild with the upcoming pattern. It looks cold and active beyond the Cutter.

Another good reminder when tracking a storm...

Hmm, looking at the ensemble members there are some good accumulations. I'll take #8 50 miles south and 50 miles west for $1000 Les.

wxnut wrote: ↑Mon Jan 01, 2024 6:13 pm Hmm, looking at the ensemble members there are some good accumulations. I'll take #8 50 miles south and 50 miles west for $1000 Les.

No doubt!

Happy New Year everyone! Hoping 2024 is a good year for all. I haven’t posted much but I do read everyone’s posts. Thanks for all you do to educate and inform. Sounds like we are i. For a busy January!

I will probably have a first call map posted Tuesday morning.

Nice model run

Good morning all! The model back and forth continued on the overnight runs and will probably continue today as well. We should be able to start to nail this thing down more tomorrow / Thursday. Right now, the heaviest snowfall is going to fall over our SE. Lesser amounts to the NW. The potential for warning criteria snowfall is good in our SE counties. Advisory level for everyone else. That is my thought process right now. This could certainly still change however. Timing wise... this primarily looks to be a late Fri night thru Sat evening type of event.

CVG, DAY and CMH all had 37 on NYD.

6Z GFS bumped back north a smidge. Windshield wiper effect on the modeling which is to be expected.

Good Morning and Les I agree we need a few more days and could be less than 24 hours before to get it correct. My biggest concern is precip type. Yes we have some cold air but is enough to keep much of the precip frozen. If we have the secondary low on this side of the mountains you can have a narrow area of moderate to heavy snow for a few hours but exactly where that sets up is almost impossible to figure out this far in advance. I believe this piece of energy will not even enter the USA until Thursday and maybe by then a better handle from all the models.

Then we have another system next week that looks rather strong and though yesterday you had I believe 2 models with a western lakes cutter and one with an eastern lakes cutter. I believe the most likely is a eastern lakes cutter which gives us a better shot of some winter weather. Then another system 3-4 days later and that one should have plenty of cold air so a better shot or winter precip.

tpweather wrote: ↑Tue Jan 02, 2024 7:04 am Good Morning and Les I agree we need a few more days and could be less than 24 hours before to get it correct. My biggest concern is precip type. Yes we have some cold air but is enough to keep much of the precip frozen. If we have the secondary low on this side of the mountains you can have a narrow area of moderate to heavy snow for a few hours but exactly where that sets up is almost impossible to figure out this far in advance. I believe this piece of energy will not even enter the USA until Thursday and maybe by then a better handle from all the models.

Then we have another system next week that looks rather strong and though yesterday you had I believe 2 models with a western lakes cutter and one with an eastern lakes cutter. I believe the most likely is a eastern lakes cutter which gives us a better shot of some winter weather. Then another system 3-4 days later and that one should have plenty of cold air so a better shot or winter precip.

A long shot Tim but the 0Z GEFS showed mainly snow for next week's system and the track was much further to the East too which I thought was interesting. But again, we've got to nail down this weekend's system first before we can begin to nail down next week. Busy busy busy no matter what happens that is for sure.

Concerning this weekend's system, wherever the deformation zone sets up, that will tell us who wins and loses with this system. The precip rate will be heavy enough to make it mainly snow. Along / SE of I-71 is the best I can do attm with trying to pinpoint that.

Les with the STJ moving right along which is often the case during and El Nino an eastward shift this season has a better shot of happening. Each system will have other parts of the equation as we know but a strong southeast ridge will be hard to get with a system coming every 2-4 days. Starting Friday and at least for 2 weeks expect one busy period for the USA.

tpweather wrote: ↑Tue Jan 02, 2024 7:19 am Les with the STJ moving right along which is often the case during and El Nino an eastward shift this season has a better shot of happening. Each system will have other parts of the equation as we know but a strong southeast ridge will be hard to get with a system coming every 2-4 days. Starting Friday and at least for 2 weeks expect one busy period for the USA.

Absolutely! It is definitely going to be busy, there is no doubt about that. We'll have to wait and see how long it takes next week's low to occlude. That is one thing that will help to determine its track. Our weekend system should be out of the way long enough that I don't think (at this time anyway) that it will impact the track since as you said, things are moving right along.

--FIRST CALL SNOWFALL FORECAST (FRI NIGHT THRU SAT AFTN)--
-Posted on Tue 1/2/24 at 7:30AM-

A winter storm is taking aim at the region this weekend. I have reviewed enough model data, performed extensive analysis, and formulated a first call snowfall forecast. A first call is usually not a final forecast, but it is issued with enough notice in order for the public to have a heads up and plenty of time to prepare.

A good chunk of the model data has amounts that are higher (even much higher in some cases) than what I am forecasting, but this is a good starting point. A conservative forecast approach, especially a few days out from a snowfall event, is typically the best technique. That allows for smaller adjustments up or down as needed versus wild swings from one end to another.

Forecast confidence is medium. There are still a lot of variables at play that I just don't have a great handle on yet. The models are struggling as well. I expect forecast confidence will increase by late tomorrow and especially Thursday.

The window of time for snowfall as is currently expected would be late Friday night through Saturday afternoon. Like amounts, the timing will likely change around a bit.

That looks good to me Trev. Can't really argue with it at all. I do think that there will be a weenie band of 4" or more but that can be put on the map later should more QPF get involved.

tron777 wrote: ↑Tue Jan 02, 2024 7:49 am That looks good to me Trev. Can't really argue with it at all. I do think that there will be a weenie band of 4" or more but that can be put on the map later should more QPF get involved.

I was debating on doing 1-3" and 3-5" but decided to go with 1-2" and 2-4". Enough model uncertainty remains to push me to keep things low for now. I do agree that a 4-6" band will probably set up somewhere, location TBD.

tron777 wrote: ↑Tue Jan 02, 2024 7:49 am That looks good to me Trev. Can't really argue with it at all. I do think that there will be a weenie band of 4" or more but that can be put on the map later should more QPF get involved.

I like it Trev, have to watch qpf trends

Bgoney wrote: ↑Tue Jan 02, 2024 7:53 am

tron777 wrote: ↑Tue Jan 02, 2024 7:49 am That looks good to me Trev. Can't really argue with it at all. I do think that there will be a weenie band of 4" or more but that can be put on the map later should more QPF get involved.

I like it Trev, have to watch qpf trends

Yes and that is another reason I kept amounts lower than what most recent guidance is showing. As we all know, QPF has tended to decrease as an event draws nearer for months now.

Trevor wrote: ↑Tue Jan 02, 2024 7:55 am

Bgoney wrote: ↑Tue Jan 02, 2024 7:53 am

tron777 wrote: ↑Tue Jan 02, 2024 7:49 am That looks good to me Trev. Can't really argue with it at all. I do think that there will be a weenie band of 4" or more but that can be put on the map later should more QPF get involved.

I like it Trev, have to watch qpf trends

Yes and that is another reason I kept amounts lower than what most recent guidance is showing. As we all know, QPF has tended to decrease as an event draws nearer for months now.

This is very true but since this is an STJ disturbance, one would think that should buck the trend. We shall soon find out. Speed of the system works against very heavy QPF.