Absolute Vorticity

It's very quiet here tonight with the big one coming. Maybe we are all afraid of jinxing it or in shock!! STOP. HAMMER TIME

Newbie who found this forum via searching for a term I wasn't familiar with in the NWS forecast. Very glad I did. Likely within a few miles of Lester, so I feel well-covered. Enjoy, everyone, and be safe!

00z GFS looks like Euro now!

Crankybear wrote: ↑Sat Jan 04, 2025 10:53 pm Newbie who found this forum via searching for a term I wasn't familiar with in the NWS forecast. Very glad I did. Likely within a few miles of Lester, so I feel well-covered. Enjoy, everyone, and be safe!

Welcome to the party pal!

At this point does it matter much what the gfs and euro are showing since they are long range models? How good are they in the short range?

Welcome wx newbies to the AV Community Family!

Nice 19-17 win for the Bengals in their last game of the 2024 season.

Currently 12 here in G'ville and progged for around 13 Sun morning.

overnight models look like they have shifted south a bit. less ice to the north but prob higher snow totals. major ice storm for much of Kentucky though. they will have a state emergency I would imagine. KC has a blizzard warning issued there and the state has deployed the national guard from what im hearing.

mainevilleweather wrote: ↑Sat Jan 04, 2025 11:30 pm At this point does it matter much what the gfs and euro are showing since they are long range models? How good are they in the short range?

Gfs and Euro are alright in the short range. Right now I think everyone should be paying attention to Hi Rez nam and hourly Hi rez rapid refresh. Most importantly too nowcast especially when Ptype might be an issue.

airwolf76 wrote: ↑Sun Jan 05, 2025 2:21 am overnight models look like they have shifted south a bit. less ice to the north but prob higher snow totals. major ice storm for much of Kentucky though. they will have a state emergency I would imagine. KC has a blizzard warning issued there and the state has deployed the national guard from what im hearing.

Definite shift south which is good for cincy area.

Virga for a period this morning

Most models now are coming into focus of more snow for Cincy, some sleet possible but the ice threat is just about dead in my mind. More snow for sure showing up for the Tri-state. Still like my 8-12" call from last night with some sleet too. Even the more northerly HRRR has all snow thru midnight tonight then sleet or frz drzl with the dry slot then back end snow on Monday. So all in all, I like what's going on. I checked radar and even STL is all snow right now. The longer they remain snow, the better it will be for us. Okay, I'll be back in a little while but wanted to pop on with some good news before I head out.

Not much change either from the boys:

.NEAR TERM /THROUGH TONIGHT/...
A low pressure system will move out of the southern Plains to the
mid Mississippi Valley today with a strengthening low level jet out
ahead of it shifting east into the Tennessee Valley. Along the
leading edge of this jet, an axis of good WAA/isentropic
lift/frontogenetic forcing will lift northeast into southern
portions of our area through late morning and into this
afternoon.

Widespread snow associated with this will develop across our
far southwest through late morning and spread northeast across
much of the rest of our southern areas through late afternoon/early
evening. The snow with this band will be heavy at times with
very low visibilities and accumulations of an inch per hour
likely for several hours. As the better forcing shifts
northward, the band of heavy snow will continue to lift
northeast across much of the rest of our area through the
evening hours, with the heaviest snow through the evening hours
affecting areas north of the Ohio River to along and south of
I-70.

As warmer air moves in aloft, some sleet will begin to mix
in with the snow across about the southern half of our area
through the evening hours with a transition to some freezing
rain eventually likely across our far south. Some mid level
drying will develop as we head into the overnight and this
should allow for a decrease in the pcpn intensity through the
second half of the night.

Snow amounts will be affected by just how much sleet is able to
mix in, but generally expect snow amounts of 4 to 7 inches
through tonight for areas along and south of I-70, with some
locally higher amounts in areas of better banding. Ice
accretion will also be a concern, especially for our far
southern tier of counties, where two to three tenths of ice
accretion will be possible. This could lead to the potential
for downed tree branches and power outages.

Temperatures will be cold with daytime highs only in the mid to
upper 20s and lows tonight in the low to mid 20s. Winds will
also begin to pick up late tonight as the surface low moves
across the eastern Tennessee Valley and the pressure gradient
begins to tighten up across our area.

No changes are currently planned for the headlines.

&&

.SHORT TERM /MONDAY/...
The surface low pressure will move off to the east through the
day on Monday with a deformation axis setting up across our area.
there is still some model variation on the exact location for
this but it looks like it will be somewhere across the southern
half of our area. As colder air moves in aloft behind the low,
any mixed pcpn will change over to all snow. Additional
snow accumulations of 1 to 3 inches will be possible for areas
to the south of I-70. This will bring storm total snow
accumulations of 5 to 10 inches across portions of our south,
most likely north of the Ohio River and south of I-70, with some
localized areas of up to a foot not out of the question.

Highs on Monday will be in the mid to upper 20s but brisk north
winds of 20 to 30 mph will result in winds chills in the single
digits to teens.

SPC has MD's out for blizz, snow, and ice in the Plains. We are watching that 1004 MB Low over OK to see where it tracks and how strong it gets.

Good Morning and sort of feel like Christmas morning and can't wait to open the packages. Really no major changes overall and should start to see some light snow at first mid-morning and then the heavier band for much of the afternoon into early evening. That part of the storm it looks like I am to low on the snow totals and looks like many folks will be nearly half foot before we transition to a mixed bad.How much sleet is involved is still a work in progress and short term models and surface reports hopefully will help. The dry slot and how long does this last and yes frz/drizzle looks likely. Then cold air wraps in around the system and back to snow on Monday with more snow. Still going 6-10 locally. Maybe just maybe some thunder as they have seen out to the west but again it happened out there with the rapid development of the system and the storm will not be getting out of hand so we will see but if it does happen usually just a few claps and we are done.

Still expecting a real nice shot of cold air mid-week with a few days below zero and again -10 - -15 has a decent chance ever at CVG. Then another system heading up from the GOM area and where does this system finally track. Still have plenty of time to work on that system and really have not looked to much as this first system is the main concern.

11z Hrrr moved up snow for cincy to between 9-10. Still looking good though!

Phr0z3n wrote: ↑Sun Jan 05, 2025 7:07 am 11z Hrrr moved up snow for cincy to between 9-10. Still looking good though!

I saw that and usually a good sign when snow starts earlier around these parts. Light at first but once we get into the afternoon some decent rates for several hours with temps staying in the low-mid 20's. One note we have a TV station around here that goes directly off the Euro and that is fine and they had been going 3-6 until late last night and moved it up and has 5-8 expect in northern kentucky they have 2-4.

tpweather wrote: ↑Sun Jan 05, 2025 7:12 am

Phr0z3n wrote: ↑Sun Jan 05, 2025 7:07 am 11z Hrrr moved up snow for cincy to between 9-10. Still looking good though!

I saw that and usually a good sign when snow starts earlier around these parts. Light at first but once we get into the afternoon some decent rates for several hours with temps staying in the low-mid 20's. One note we have a TV station around here that goes directly off the Euro and that is fine and they had been going 3-6 until late last night and moved it up and has 5-8 expect in northern kentucky they have 2-4.

Definitely looks faster when compared to 12z/6z nam precip shield. 12z Hrrr 12znam should take this into account when it’s out.

Hrrr has around an inch qpf for cvg before the mix begins around 11pm give or take an hour(for cvgland)

Bgoney wrote: ↑Sun Jan 05, 2025 7:32 am Hrrr has around an inch qpf for cvg before the mix begins around 11pm give or take an hour(for cvgland)

Yep even at 8-9 pm 850 temps get real close.

Tim , the only thing I can think of for those lesser amounts is they are expecting the mix to start earlier as a possibility mentioned in above post. If that were the case since that is a time when heaviest qpf is falling and snowfall rates at 1-2” per hour , a 2-3 hour earlier start with the mix would definitely eat into the heavier accumulation(cvg). Not saying it will happen but what they are currently thinking, and depending on track not out of the question.

Bgoney wrote: ↑Sun Jan 05, 2025 8:00 am Tim , the only thing I can think of for those lesser amounts is they are expecting the mix to start earlier as a possibility mentioned in above post. If that were the case since that is a time when heaviest qpf is falling and snowfall rates at 1-2” per hour , a 2-3 hour earlier start with the mix would definitely eat into the heavier accumulation(cvg). Not saying it will happen but what they are currently thinking, and depending on track not out of the question.

Totally agree Bgoney. I had 2-4 for the Sunday afternoon and I believe closer to 6 inches. Can somebody get a foot and we know that Mother Nature does not pay attention to weather maps,mets and does her own thing. Still going total for the entire storm 6-10 inches. Sleet is always a pain not in cutting down snow totals but where it sets up. Usually a narrow area but sometimes even just a few hours. Overnight frz/drl and temps probably in the upper 20's so I don't see us getting above 32 and that will be more towards Lexington and eastern Ky could see some low 40's before cold air pushes back in

Great storm to follow and for us locally having cold air a few days before the storm is no doubt a huge key in getting a big snow. 6 inches locally is big around here and my guess over the past decade maybe 5 storms with totals over 6 inches.

12z HRRR. not much dry slot but a ton of sleet

this storm is far reaching I can see half the state of Kentucky without power

No changes for me and will have my last forecast at 9pm Monday evening.

What’s a good resource for determining where snow is reaching the ground vs virga? MPING isn’t working for me atm.