Absolute Vorticity

12Z Euro just refuses to get on board. It doesn't show much for frontogenic snows to our north for Thurs and the 1st wave that brings in the return flow from the Gulf is weak and the vast majority misses our forecast area to the south. Most of the snow comes on Friday with the second northern wave that drops in. QPF at CVG is 0.13" and that is for Friday. CVG Land gets very little until then on this run. No phasing or interaction really to speak of. I-70 folks do a little better getting around 0.18" using DAY.

UKMET

Euro 12z - it continues to show that dry slot, so it cuts down the snow for a point.

fyrfyter wrote: ↑Tue Jan 16, 2024 1:31 pm Euro 12z - it continues to show that dry slot, so it cuts down the snow for a point.

IMG_0796.jpeg

We're in no man's land between the waves of snow too on this run which is certainly a concern. One thing is for certain, I think location is going to be very key with this system and snowfall totals are going to have a wide range depending on where you live. For our local area, I currently favor the I-70 Crew to get the higher totals and CVG Land, the lowest. Just the way our luck has been going. Hopefully, we will see something positive occur in future model runs. Still plenty of time to see how things shape up.

tron777 wrote: ↑Tue Jan 16, 2024 1:35 pm

fyrfyter wrote: ↑Tue Jan 16, 2024 1:31 pm Euro 12z - it continues to show that dry slot, so it cuts down the snow for a point.

IMG_0796.jpeg

We're in no man's land between the waves of snow too on this run which is certainly a concern. One thing is for certain, I think location is going to be very key with this system and snowfall totals are going to have a wide range depending on where you live. For our local area, I currently favor the I-70 Crew to get the higher totals and CVG Land, the lowest. Just the way our luck has been going. Hopefully, we will see something positive occur in future model runs. Still plenty of time to see how things shape up.

Every model I’ve looked at shows that NML wedge of lesser influence , in some form or another, coming up-river and right into cvgland

I think a 1-3” call is a safe call! Just hope the Nam follows another model or they are follow Nam and euro. Just need to get numbers and feel confident

Bgoney wrote: ↑Tue Jan 16, 2024 1:59 pm

tron777 wrote: ↑Tue Jan 16, 2024 1:35 pm

fyrfyter wrote: ↑Tue Jan 16, 2024 1:31 pm Euro 12z - it continues to show that dry slot, so it cuts down the snow for a point.

IMG_0796.jpeg

We're in no man's land between the waves of snow too on this run which is certainly a concern. One thing is for certain, I think location is going to be very key with this system and snowfall totals are going to have a wide range depending on where you live. For our local area, I currently favor the I-70 Crew to get the higher totals and CVG Land, the lowest. Just the way our luck has been going. Hopefully, we will see something positive occur in future model runs. Still plenty of time to see how things shape up.

Every model I’ve looked at shows that NML wedge of lesser influence , in some form or another, coming up-river and right into cvgland

NML - Seems to be the theme of this winter, what few opportunities we've had.

Bgoney wrote: ↑Tue Jan 16, 2024 1:59 pm

tron777 wrote: ↑Tue Jan 16, 2024 1:35 pm

fyrfyter wrote: ↑Tue Jan 16, 2024 1:31 pm Euro 12z - it continues to show that dry slot, so it cuts down the snow for a point.

IMG_0796.jpeg

We're in no man's land between the waves of snow too on this run which is certainly a concern. One thing is for certain, I think location is going to be very key with this system and snowfall totals are going to have a wide range depending on where you live. For our local area, I currently favor the I-70 Crew to get the higher totals and CVG Land, the lowest. Just the way our luck has been going. Hopefully, we will see something positive occur in future model runs. Still plenty of time to see how things shape up.

Every model I’ve looked at shows that NML wedge of lesser influence , in some form or another, coming up-river and right into cvgland

Agreed. Even the snowier models have the weak spot which may sharpen up even on the globals in future runs. Current thinking is 1-2” for the metro and points west/southwest. Can always adjust up if need be. But I hate to adjust down. And I’ll be honest I’m still a little gun shy after that terrible bust earlier in the month,

Looks like EPS is coming in with a range of .15”-.20” max for the region

I am gun shy too Trev. We have every right to approach this one with caution. I like a 1-3" range with your best chance at 3" being the I-70 Crew and 1" south of the river like my hood unfortunately. Something along those lines anyway.

Trevor wrote: ↑Tue Jan 16, 2024 2:10 pm

Bgoney wrote: ↑Tue Jan 16, 2024 1:59 pm

tron777 wrote: ↑Tue Jan 16, 2024 1:35 pm

fyrfyter wrote: ↑Tue Jan 16, 2024 1:31 pm Euro 12z - it continues to show that dry slot, so it cuts down the snow for a point.

IMG_0796.jpeg

We're in no man's land between the waves of snow too on this run which is certainly a concern. One thing is for certain, I think location is going to be very key with this system and snowfall totals are going to have a wide range depending on where you live. For our local area, I currently favor the I-70 Crew to get the higher totals and CVG Land, the lowest. Just the way our luck has been going. Hopefully, we will see something positive occur in future model runs. Still plenty of time to see how things shape up.

Every model I’ve looked at shows that NML wedge of lesser influence , in some form or another, coming up-river and right into cvgland

Agreed. Even the snowier models have the weak spot which may sharpen up even on the globals in future runs. Current thinking is 1-2” for the metro and points west/southwest. Can always adjust up if need be. But I hate to adjust down. And I’ll be honest I’m still a little gun shy after that terrible bust earlier in the month,

That’s always been my approach. Better to add than take people’s snow away from them. The pitch fork and torches crowd would be at the back door

I am really happy to see the Nam coming around

18Z NAM QPF:

CVG - 0.12"
HAO - 0.19"
MGY - 0.22"
DAY - 0.26"
CMH - 0.25"
FGX - 0.18"

That dry slot is still too close for comfort for folks south of the River.

18Z RGEM has a general 0.20-0.30" for the Region but that dry slot does work its way up into Cincy. I just don't like the fact that we keep seeing that.

The boys latest thinking:

Below normal temps are on tap through most, if not all, of the long
term period. And not to mention, this will occur within a stretch of
climatological annual minimums, which will translate to several days
with very cold/dangerous wind chills, especially Saturday/Sunday.

But before we return to the anomalous cold, there will several
opportunities for light snow across various portions of the ILN FA,
with the greatest potential for widespread accumulating snow likely
evolving Thursday night through early Friday afternoon.

As we progress Thursday morning into the afternoon, some light snow
should develop well in advance of the primary S/W, which quickly
translate to the ENE through the TN Vly during the daytime period.
This initial batch of light snow, which is likely to develop N of
the I-70 corridor stretching from nrn IL through nrn OH, will be the
byproduct of a mid/upper level jetstreak propagating through the
region. Still quite a bit of uncertainty as it relates to the
positioning of this W-E oriented light snow band, with the best
potential for a few tenths of an inch of snow accumulation Thursday
afternoon N of I-70.

By Thursday evening, the S/W will progress E into the srn OH Vly,
with an additional band of snow developing more across srn/central
KY. These two initially-distinct areas of light snow should
eventually congregate/merge late into the evening, with light snow
overspreading the remainder of the area late evening into the
overnight. There will be quite a bit of antecedent dry air in the
LLs to overcome before the profile becomes sufficiently saturated to
allow for the snow to make it to the ground. The best chance for at
least 0.5" of snow through the day Thursday will be near/N of I-70
and W of I-71, with ern parts of the ILN FA potentially remaining
dry through late afternoon.

The better forcing will arrive late Thursday night through Friday
morning as a fairly sharp S/W pivots in from the NW. This will
promote a progressive/steady increase in both coverage and intensity
of light snow after midnight, with high confidence in widespread
light accumulations Friday morning through early afternoon.

So... all in all, there appear to be three separate sources of
forcing, all of which will produce snow across the ILN FA through a
36 hour period -- focused at different times and in different
locations. The generally cold temperatures will support snow ratios
much greater than 10:1 (with 15:1 to 18:1 appearing the most likely
early Friday morning through early afternoon). Thus, even modest QPF
amounts should produce greater than 1 inch of accumulation.

Overall, the ensemble probabilities continue to suggest a widespread
1-3 inches of snow through the duration of the Thursday-Friday time
frame, but with low confidence in specific locations of the higher
amounts. With these types of higher-ratio events, certainly small
differences/increases in liquid-equivalent precip can have greater
impacts on the overall accumulation. And this is why 3-4" certainly
cannot be ruled out, especially near/N of I-70 into central OH where
the ensemble probability signal is the most robust. This being said,
did not have confidence at this juncture to move forward with any
headlines, but would certainly expect, at the very least, for a
large advisory (potentially covering the entire ILN FA) to
eventually be needed, depending on how data trends over the next 24
hours. So... will continue to mention accumulating snow in the HWO,
as this is still out on Day 2/3 of the forecast.

Temps on Friday will be a bit tricky as sfc CAA may begin relatively
early in the day near/W of I-71, which may allow for an "early" high
temp to be reached before plateauing and eventually trending
colder once again by late afternoon. The reinforcing arctic air
will move in late Friday/night, with air temps dipping into the
single digits once again Saturday morning and highs topping out
generally in the mid to upper teens during the day.

18Z GFS QPF.

CVG - 0.32"
HAO - 0.30"
MGY - 0.31"
DAY - 0.25"
CMH - 0.29"
FGX - 0.33"

18Z GEFS Mean has around 0.20" of QPF for most of the region.

tron777 wrote: ↑Tue Jan 16, 2024 6:35 pm 18Z GEFS Mean has around 0.20" of QPF for most of the region.

I noticed that . That’s a drop in qpf for the region from previous ensembles(GFS)

18Z Euro QPF

CVG - 0.17"
HAO - 0.14"
MGY - 0.12"
DAY - 0.10"
CMH - 0.14"
FGX - 0.19"

The trends in a lot of the guidance today is for the vast majority of the snow to come later Thurs night into the day on Fri. From a traveling standpoint, Fri AM commute could certainly be impacted. Fri afternoon's drive depends on how long the snow lasts and the duration will be determined by how much phasing we see.

From my FB page...

And the problems remain. 00z NAM is well North of us. We only get snow North of the river for 9 hours, and get an inch.

Found this gem….it’s about right! 54% of the country is snow-covered. Look at the whole on top of Cincinnati!

00z rundown...

Continue to watch that dryslot which has been a concern of mine for a couple days.

Looking at the above maps... I stand by my 1-3" call. An inch for CVG Land and up to 3" for the I-70 Crew. Fri AM commute will be troublesome in many areas, worse as one goes north throughout our forecast area.