Absolute Vorticity

Starting off with the Sun clipper, Most models show a band of 1-2" of snow falling mainly north of the river. A couple of models do show the band more over CVG Land. I think of the northern models are right CVG gets a dusting and 1-2" for N Cincy burbs and I-70 Crew. Switch that call around if the southern models are right. I am leaning towards the northern solutions right now.

For Tues, if the moisture and the cold front can meet up right, a band of snow is possible on the NW edge of the precip shield which is how the overnight guidance trended. ENS members have a few phased and amp'ed up members too so this system still needs to be watched. The Sun clipper is the main concern first.

An early look from the boys:

The Arctic high pressure system will drift further south Saturday
night, but likely keep much of the ILN fa dry overnight. As we
progress into Sunday morning, the focus shifts towards a quick
moving shortwave trough that has the potential for producing
accumulating snowfall. The associated surface low will track through
Canada and may drift towards the upper Great Lakes region. With this
being more of a Clipper system, the overall moisture in the
atmosphere will limit the ability for significant accumulating
snowfall. However, ensembles and some deterministic guidance still
suggest that locations in west-central Ohio and eastern IN could
observe 1-2" of snow from this system. These are the locations where
PoPs are now in likely range. Still, based on the track, would not
be surprised if locations near the Tristate and the Scioto Valley
also observed near or just over an inch of snow from this system.
Trends in the track of the low and the overall moisture availability
will be key as we continue to monitor this event.

We won`t see much of a break in the action as the next system moving
in may bring additional snowfall Monday into Tuesday. A low pressure
system located in the Northern Plains region will shift eastward
through the Upper Midwest on Monday. The track of the low currently
shows it moving through the Great Lakes towards the eastern CONUS,
so impacts from this low will primarily be felt across our northern
counties. However, a low pressure system from the Gulf will lift
northward Monday night and will usher in a plume of moisture that
will help provide increased PoPs to our southern and eastern
counties for Tuesday. The WAA from this system could end up melting
some ice crystals and leaving a rain-snow mix for counties
near/south of the OH river during the day. On the back end,
additional snow accumulations will be possible Tuesday night.
Ensembles don`t seem to favor significant snow accumulation
potential for now, but this will be another system to closely
monitor.

Another Arctic high pressure system builds back in on Wednesday,
providing drier conditions with below normal temperatures through
the remainder of the period.

9Z SREF Mean has about a 1/2" at CVG to around an inch for I-70 Crew... that is for the Sunday clipper.

The timing has sped up on the clipper too, which is typical. Looks to be a late morning to afternoon event. Outta here by late afternoon or so. A nice band of 1-2" iso 3" coming down I-74 right into the Tri-state N of the river.

12Z NAM QPF

CVG - 0.08"
HAO - 0.15"
MGY - 0.19"
DAY - 0.16"
CMH - 0.08"

IND - 0.11" - They may finally get their first 1" plus snowfall.

3KM NAM has that band a bit further to the south running from S of KIND right into NKY. Has 2" for CVG.

tron777 wrote: ↑Fri Jan 21, 2022 9:36 am 3KM NAM has that band a bit further to the south running from S of KIND right into NKY. Has 2" for CVG.

Here is the NAM 3km visual on 24hr snowfall for Sunday...

12Z RGEM is mostly north of the river and showing the best action for our I-70 Crew.

12Z GFS is way north with the clipper on this run. Keeps the best snows N of I-70.

I like ILN’s forecast/probs. Think that’s a good one to roll with for now.

It's sad that we get excited over 1" snow. Times are rough I know LOL

cloudy72 wrote: ↑Fri Jan 21, 2022 11:15 am It's sad that we get excited over 1" snow. Times are rough I know LOL

Due to the further north track, the Tues system that this thread also covers is looking better. 12Z GFS QPF for that system are as follows...

CVG - 0.20"
DAY and CMH - in that 0.15" ballpark

This is a nice increase actually from the overnight run. Phasing is a bit better on this run in part because of the Sun clipper tracking more to the north. If I had my way, we'd all get missed from the Sun clipper in the hopes of a better outcome for Tues. We'll cover it as it occurs lol

12Z CMC also north w/ the Sun clipper. I-70 Crew looks good.

We are def on the same page Tim. If I-70 Crew gets it and we don't, I am okay with that. It'll help us all out for Tuesday.

12Z GEFS Mean between both systems paints 2-4" across a good chunk of the forum area. This is a snowfall mean counting both systems.

12Z UKIE gives most of us an advisory type snow for Sunday's clipper. Pretty beefy on this run. 10:1 Ratio:

UKIE is a southern OV special for Tuesday with regards to moisture. Mix of rain and snow depending on elevation. Too late of a phase.

tron777 wrote: ↑Fri Jan 21, 2022 12:09 pm UKIE is a southern OV special for Tuesday with regards to moisture. Mix of rain and snow depending on elevation. Too late of a phase.

That is usually a bias for the UKIE but if it matches the Euro later then we need to look at it more carefully. The mjo is in the cod which again is not a bad thing because of where it entered form phase 8. The latest as it remaining in the cod but heading more towards phase 2 or 3 which again if this happens in February those are not bad phases for us.

tpweather wrote: ↑Fri Jan 21, 2022 12:18 pm

tron777 wrote: ↑Fri Jan 21, 2022 12:09 pm UKIE is a southern OV special for Tuesday with regards to moisture. Mix of rain and snow depending on elevation. Too late of a phase.

That is usually a bias for the UKIE but if it matches the Euro later then we need to look at it more carefully. The mjo is in the cod which again is not a bad thing because of where it entered form phase 8. The latest as it remaining in the cod but heading more towards phase 2 or 3 which again if this happens in February those are not bad phases for us.

UKIE has not been doing well this winter so I wouldn't pay too much attn to it. GFS has been doing well and the Euro on occasion too like with the last one that completely missed us. Euro was south the entire time. GFS usually handles the polar jet better, ie clipper systems so we'll see how it performs on Sunday. For Tues, the GFS is the best solution for us attm. Along with GEFS.

Euro has been the lowest for QPF on Sunday and has been giving us nothing on Tues due to no phasing. Let's see what changes the 12Z run has in store in the next hour.

Euro QPF for Sunday clipper:

CVG = 0.09"
DAY = 0.12"
CMH = 0.09"

Euro is an improvement and closer to most of the other models now for Sunday. For Tues... still having major timing issues. Northern stream is way out in front of the S wave, I think it was Day 6 or 7, the Euro has a nice snow event with a good phase. It's had timing issues with this system ever since.

15Z SREF Mean for DAY and CMH is about an inch. About a 1/2" for the Tri-state / Metro / CVG area. This is for the Sunday clipper.

18Z NAM is north with the clipper, and faster too.

18Z GFS also north...