Absolute Vorticity

Trevor wrote: ↑Tue Jan 02, 2024 11:21 am Because of marginal thermals, ratios will be <10:1. Just something to keep in mind. Total concrete.

Agreed. 7 or 8:1 is more like it. Heart attack special!

GEFS SLP members look good for the primary low track. It backs up what the OP GFS is selling. I think we have some really good model agreement thus far.

GFS solution brings mixing issues ever so closer south of 71

Bgoney wrote: ↑Tue Jan 02, 2024 11:48 am GFS solution brings mixing issues ever so closer south of 71

Thermals are marginal for sure. Will probably help mitigate travel impacts to some extent in areas that see heavier snow...

Trevor wrote: ↑Tue Jan 02, 2024 11:54 am

Bgoney wrote: ↑Tue Jan 02, 2024 11:48 am GFS solution brings mixing issues ever so closer south of 71

Thermals are marginal for sure. Will probably help mitigate travel impacts to some extent in areas that see heavier snow...

You know the old saying... you've got to smell the rain to see the snow.

tron777 wrote: ↑Tue Jan 02, 2024 11:57 am

Trevor wrote: ↑Tue Jan 02, 2024 11:54 am

Bgoney wrote: ↑Tue Jan 02, 2024 11:48 am GFS solution brings mixing issues ever so closer south of 71

Thermals are marginal for sure. Will probably help mitigate travel impacts to some extent in areas that see heavier snow...

You know the old saying... you've got to smell the rain to see the snow.

For us in the SE crew division that saying usually leads to PTSD (Post traumatic Snow disappointment)

Bgoney wrote: ↑Tue Jan 02, 2024 12:26 pm

tron777 wrote: ↑Tue Jan 02, 2024 11:57 am

Trevor wrote: ↑Tue Jan 02, 2024 11:54 am

Bgoney wrote: ↑Tue Jan 02, 2024 11:48 am GFS solution brings mixing issues ever so closer south of 71

Thermals are marginal for sure. Will probably help mitigate travel impacts to some extent in areas that see heavier snow...

You know the old saying... you've got to smell the rain to see the snow.

For us in the SE crew division that saying usually leads to PTSD (Post traumatic Snow disappointment)

Very true... no denying that. It will come down to the wire as is typically the case.

Truthfully....is it not an OV Snow Storm if there isn't the following ingredients:
1. Rain/Snow line too close
2. Iffy Thermals
3. Cold Rain
4. PTSD as mentioned above
5. Tears that will not freeze due to #2

I am sure there are more.

Liking the trends so far this morning!

BookNerdCarp wrote: ↑Tue Jan 02, 2024 12:43 pm Truthfully....is it not an OV Snow Storm if there isn't the following ingredients:
1. Rain/Snow line too close
2. Iffy Thermals
3. Cold Rain
4. PTSD as mentioned above
5. Tears that will not freeze due to #2

I am sure there are more.

Good post Matt! It's how we roll.

The ICON is falling into line with the GFS and the Canadian.

Anyone seen the Euro yet and can comment? I don't have a good resource when I'm at work.

1 to 3 for us from the euro. Looks weaker than the previous run.

EU definitely showing mixing issues for some of the qpf that falls

Thanks guys... I'll check it more closely after work today.

Bgoney wrote: ↑Tue Jan 02, 2024 1:35 pm EU definitely showing mixing issues for some of the qpf that falls

I agree and that has been my issue with the system. The cold is marginal and if we are lucky temps between 30-32 with snow but I can see where temps get up to 35 or so and you may have rain,snow but plenty of melting. This far out hard for me to put an accumulation forecast out. I know Trev has done so but I don't feel confident enough and it may be late this week because the temp profile is tricky.

tpweather wrote: ↑Tue Jan 02, 2024 1:41 pm

Bgoney wrote: ↑Tue Jan 02, 2024 1:35 pm EU definitely showing mixing issues for some of the qpf that falls

I agree and that has been my issue with the system. The cold is marginal and if we are lucky temps between 30-32 with snow but I can see where temps get up to 35 or so and you may have rain,snow but plenty of melting. This far out hard for me to put an accumulation forecast out. I know Trev has done so but I don't feel confident enough and it may be late this week because the temp profile is tricky.

It will all depend on where the deformation band sets up and we probably won't have that pinned down until Thursday IMO at the earliest. Rates will overcome the surface temps and I truly feel that there will be a nice deform band of snow with this system. Will it be us or SE Crew? To be determined...

tpweather wrote: ↑Tue Jan 02, 2024 1:41 pm

Bgoney wrote: ↑Tue Jan 02, 2024 1:35 pm EU definitely showing mixing issues for some of the qpf that falls

I agree and that has been my issue with the system. The cold is marginal and if we are lucky temps between 30-32 with snow but I can see where temps get up to 35 or so and you may have rain,snow but plenty of melting. This far out hard for me to put an accumulation forecast out. I know Trev has done so but I don't feel confident enough and it may be late this week because the temp profile is tricky.

Totally agree Tim , , 850s look good but surface temps and a warm layer at the 925mb need to be resolved

tpweather wrote: ↑Tue Jan 02, 2024 1:41 pm

Bgoney wrote: ↑Tue Jan 02, 2024 1:35 pm EU definitely showing mixing issues for some of the qpf that falls

I agree and that has been my issue with the system. The cold is marginal and if we are lucky temps between 30-32 with snow but I can see where temps get up to 35 or so and you may have rain,snow but plenty of melting. This far out hard for me to put an accumulation forecast out. I know Trev has done so but I don't feel confident enough and it may be late this week because the temp profile is tricky.

My rule is that if I have at least medium confidence, I will put out numbers. Too often people will wait until a day even before a storm to get into specifics. For some reason there is a mentality among Mets and forecasters that as soon as numbers are released, they can’t be changed. Forecasts, much like the atmosphere, are largely fluid and ever changing. Accuracy is important, but it’s also silly to wait until last minute to issue a snowfall forecast. With proper explanation of uncertainty, the general public overall understands…and they generally appreciate lead time versus being precise to the exact inch. Some are trolls of course and will always call out a forecast that’s even only slightly off, but those kind of people exist in every area of life lol. Just my two cents.

Great Post Trev. To me its always the confidence level and many times I will be out on a limb by myself and it breaks I fail and other times sturdy as can be. Good thing about this forum is several folks will put out forecasts and there are several ways to skin a cat. Everyone has their method whether it be from a model standpoint or pattern standpoint. Most folks on here understand the old man goes pattern first and then looks at the models to see if they agree. When the pattern and model agree then I have more confidence but sometimes I disagree with the models and then I look deeper into the pattern side of things. This weekend I believe we get some winter weather but my problem is the possible mixing issues and that is why I need a few more days to throw out possible accumulations. Trev you may be dead on and I may end up going that way but until my brain and gut feel the same I will just wait this out a tad longer than normal

Latest thinking from the boys:

.LONG TERM /THURSDAY THROUGH MONDAY/...
A progressive shortwave moving across the Great Lakes states will
bring mostly cloud cover to the Ohio Valley Wednesday night into
Thursday morning. High pressure and dry weather will return by
Thursday afternoon. This high will be centered over the region
Friday.

Meanwhile, a potent low pressure system will be organizing over the
Gulf Coast and will begin ejecting northeasterly Friday night,
reaching the Carolinas Saturday afternoon. Latest guidance shows a
southeasterly low level jet pulling moisture off the Atlantic Ocean
and bringing it back across West Virginia into southern Ohio. While
deterministic guidance still varies, there is increasing confidence
that precipitation will be occurring Saturday. Based on model
soundings, it appears the vertical temperature profile will make for
a difficult rain vs. snow forecast. For now, have generally a
rain/snow mix where the precipitation is most widespread in the
southeast, with mainly light snow back to the northwest.

While confidence in precipitation type is low, have opted for an HWO
mention for possible snow accumulations southeast of Interstate 71.

Weak high pressure will build into the region on Sunday into Monday.
There is still a notable lack of January-like cold air through the
extended period, with near to above normal temperatures
persisting.

I have no idea if this means anything or not, but in the Sierra... winter weather advisories were upgraded earlier today to winter storm warnings. I don't know if that means that our shortwave will be stronger then is currently being modeled? Just an observation and it may not mean a thing.

tron777 wrote: ↑Tue Jan 02, 2024 4:45 pm I have no idea if this means anything or not, but in the Sierra... winter weather advisories were upgraded earlier today to winter storm warnings. I don't know if that means that our shortwave will be stronger then is currently being modeled? Just an observation and it may not mean a thing.

Not sure either but many of these systems we are starting to see come in from the pacific are stronger imo. Another item is high pressures we are starting to see in Canada and moving into the northern USA. These are starting to get a tad stronger and though not pure arctic air the air is cold enough and should help in adding a little more cold to these storms.

18Z GFS is definitely coming in weaker unfortunately. A tenth of an inch at CVG for QPF. Time to throw those rotten tomatoes at Trev!

tron777 wrote: ↑Tue Jan 02, 2024 5:00 pm 18Z GFS is definitely coming in weaker unfortunately. A tenth of an inch at CVG for QPF. Time to throw those rotten tomatoes at Trev!

Still 4 days out. Not much of a concern in my opinion. We often see these fluctuations 3-5 days out. We shall see.