Absolute Vorticity

tron777 wrote: ↑Fri Feb 09, 2024 2:27 pm I like the prelim 1-3" call Trev. Makes sense and it is very reasonable. Do you like my thread title?

I agree and the timing is what I like about this system. Going to be interesting because this system is gaining strength as it heads this way and looking at how the atmosphere is would not be surprised if some thunderstorms in southern Kentucky late Monday forms and this can also push heavier moisture further north. Wish it was colder but again never perfect around here.

Our vort for Monday was at least partially sample for the 12z suite , but 0z should be fully sampled

18Z NAM is weak and SE but it is still in the longer range of the meso models.

The 18Z GFS is coming in a bit stronger this evening and the track still looks good. Hammers 71 and points N and E. The low track is a classic Cincy to CMH track for decent snows but we need hvy precip rates. We have nighttime on our side for the bulk of the event. Just need that low to deepen as early as possible.

CVG
Charles gets some nice powder from the 18Z GFS! Wow!

ESP - East Stroudsburg, PA

Good Evening and still 72 hours or so away from this system to be impactful. Again we all know the problems and we need this system to get stronger but also time it correctly where most of the precip is between say 6pm Monday- 9am Tuesday. That alone does not mean snow but we get the stronger system and the timing correct somebody locally should get in on some accumulation. No doubt the ground has been warm lately but if the snow is heavy enough it will start to accumulate. This is not the kind of system that shuts down things but could make it a little slippery Tuesday morning.

Slight trend today in both GEFs/EPS compared to each of there OPs . There ensembles are slightly more south with the track of the low. With such a small axis of some accumulations any shift is crucial

Bgoney wrote: ↑Fri Feb 09, 2024 6:54 pm Slight trend today in both GEFs/EPS compared to each of there OPs . There ensembles are slightly more south with the track of the low. With such a small axis of some accumulations any shift is crucial

No doubt Bgoney and at least we have something to track.

really the only take away for me today is that every single model has the storm and has accumulating snow but you can still see quite a variety of solutions still on the table on what to expect. my guess is by later tomorrow we should have a lot more confidence in what to expect.

We’ve had a handful of these southern lows moving into a marginal airmass this season but those were pretty straightforward in that they weren’t bringing their own cold air with them. This one atm , does bring its own cold pool with it as long as precipitation is heavy , so the track actually matters this time. Mods still show a skinny axis of accumulating snows . Either side of this axis you probably get an inch or less. For know, I like the 1-3” amounts wherever that axis sets up . How much qpf is used During the mix period and warm wet ground before snow actually starts to accumulate is a tough call, something snow maps can’t figure in the equation. Night time will help but still have to go through the process. Lots of time for changes, up or down . If the axis is centered 20 miles south of say 71 , north of 71 would be in the dreaded inch or less and vice versa if axis is north of 71.

Good Morning and great post Bgoney. This kind of system really will be a now cast imo. Sure models can try and narrow the area where snow falls but again you have a storm that is still developing and getting stronger as it heads northeast. I like the call of 1-3 somewhere nearby and so far that is very near us with the best forcing occuring near I-71 during the evening into early overnight. Will watch the shorter term models over the next few days but again with the temp profile on the edge I believe surprises will happen.

Of course concerns is temperature and warm ground but something we saw several times this season and storms as they get closer are weaker than forecast and does that trend continue or does this one gain the strength the models are showing. We need the stronger system or we end up with a cold rain and 38 degrees.

tpweather wrote: ↑Sat Feb 10, 2024 8:33 am Good Morning and great post Bgoney. This kind of system really will be a now cast imo. Sure models can try and narrow the area where snow falls but again you have a storm that is still developing and getting stronger as it heads northeast. I like the call of 1-3 somewhere nearby and so far that is very near us with the best forcing occuring near I-71 during the evening into early overnight. Will watch the shorter term models over the next few days but again with the temp profile on the edge I believe surprises will happen.

Of course concerns is temperature and warm ground but something we saw several times this season and storms as they get closer are weaker than forecast and does that trend continue or does this one gain the strength the models are showing. We need the stronger system or we end up with a cold rain and 38 degrees.

Thanks Tim, we can throw out numbers here early on of the event, but there’s no way if I was a TV met I’d give out amounts this early for this event given the uncertainty of track . Fifty miles more south(north)and we’re all in the dreaded inch or less

NAM shows an overall weak system. GFS still looks really nice. GEFS does too. This can be a nice event if the low deepens at the right time as the GFS family suggests. GFS really has been rock solid over the last several days for accumulating snow Mon night. GEFS is really juiced up!

6Z Euro was GFS like too,. CMC still weak.

Weak models: NAM, CMC, RGEM Stronger models: GFS, GEFS, Euro, and EPS.

If this keeps up, I may ride the GFS and Euro and go with 2-4". That would certainly be possible on grassy areas, car tops, etc. Not as much on pavement surfaces obviously.

12Z GEFS Mean at a 10:1 Ratio:


Taking the warm ground into account and even worse ratios then 10:1, I think a winter weather advisory event should cover it with 2-4" being doable.

I edited the thread title for 12-13th due to this mainly being a later Mon into early Tues event.

Add the UKIE to the weaker model camp. Hopefully we see the Euro stick to the more GFS like solution. I don't see why it wouldn't. If the stronger solutions are real, we should see the meso's come around tomorrow.

tron777 wrote: ↑Sat Feb 10, 2024 12:48 pm Add the UKIE to the weaker model camp. Hopefully we see the Euro stick to the more GFS like solution. I don't see why it wouldn't. If the stronger solutions are real, we should see the meso's come around tomorrow.

The 12Z? It seems stuck on Pivotal.

Trentonwx06 wrote: ↑Sat Feb 10, 2024 12:51 pm

tron777 wrote: ↑Sat Feb 10, 2024 12:48 pm Add the UKIE to the weaker model camp. Hopefully we see the Euro stick to the more GFS like solution. I don't see why it wouldn't. If the stronger solutions are real, we should see the meso's come around tomorrow.

The 12Z? It seems stuck on Pivotal.

Yeah, it is. Euro is at least running now lol UKIE is out on the Meteocentre site.

Euro is coming in a touch stronger / colder versus 0Z. We get to 32 degrees at CVG by midnight or 1am Mon night then drop into the upper 20s by the time the event ends Tues morning. Rain to snow as the heavier deform bad moves thru.

CVG
990 MB over WV so that deform band although skinny, should be rocking where it sets up.

FGX - Matt

tron777 wrote: ↑Sat Feb 10, 2024 1:12 pm Euro is coming in a touch stronger / colder versus 0Z. We get to 32 degrees at CVG by midnight or 1am Mon night then drop into the upper 20s by the time the event ends Tues morning. Rain to snow as the heavier deform bad moves thru.

CVG

Code: Select all

TUE 00Z 13-FEB   4.5     1.6    1001      89      99    0.19     548     548    
TUE 06Z 13-FEB  -0.1    -4.3    1005      92     100    0.62     540     536    
TUE 12Z 13-FEB  -2.5    -5.2    1013      85       7    0.11     545     534

990 MB over WV so that deform band although skinny, should be rocking where it sets up.

Hey Les and that is key word skinny. A narrow band of heavier snow but you are talking maybe 30 miles wide for the heaviest band. Still 2 days away so hopefully we can narrow it down but like most systems they have a mind of their own and can surprise good or bad at the end

tpweather wrote: ↑Sat Feb 10, 2024 1:21 pm

tron777 wrote: ↑Sat Feb 10, 2024 1:12 pm Euro is coming in a touch stronger / colder versus 0Z. We get to 32 degrees at CVG by midnight or 1am Mon night then drop into the upper 20s by the time the event ends Tues morning. Rain to snow as the heavier deform bad moves thru.

CVG

Code: Select all

TUE 00Z 13-FEB   4.5     1.6    1001      89      99    0.19     548     548    
TUE 06Z 13-FEB  -0.1    -4.3    1005      92     100    0.62     540     536    
TUE 12Z 13-FEB  -2.5    -5.2    1013      85       7    0.11     545     534

990 MB over WV so that deform band although skinny, should be rocking where it sets up.

Hey Les and that is key word skinny. A narrow band of heavier snow but you are talking maybe 30 miles wide for the heaviest band. Still 2 days away so hopefully we can narrow it down but like most systems they have a mind of their own and can surprise good or bad at the end

This one could be a sleeper if we get the SE KY and low into WVA track and keep it strong like the Euro suggests. I think modeled QPF maybe low in that regard. System will then transfer its energy to the EC Low but the stronger the primary low is, IMO, the longer it should take to weaken. A quick hitting 6-8 hour snowfall is how this system is looking to me. 1-2" per hour rates are possible somewhere. Again, just don't know yet where? To me, the goal posts are from I-70 to I-64 range so that put us in a good spot right now.