Absolute Vorticity

A solid 2-4" event for the Tri-state on the 18Z RGEM for Tues afternoon into Tues night.

Scotty D is weighing in:

0.11" QPF at CVG from the 18Z Euro for Tues.

lol , the NAM . We got mini NAM’d and central KY got Mega NAM’d (12-15”). Only useful thing from that is where that narrower heavier band may set up , atm, in central-ish KY of 3-5”. No changes from me locally

Bgoney wrote: ↑Sun Feb 09, 2025 7:16 pm lol , the NAM . We got mini NAM’d and central KY got Mega NAM’d (12-15”). Only useful thing from that is where that narrower heavier band may set up , atm, in central-ish KY of 3-5”. No changes from me locally

That should be the case and someone is going to get 4 or 5 inches south of here. See nothing at all to change the forecast Bgoney.

Nam not giving up lol

Sref and Canadian, too. Euro and GFS remain the two southern models.

We have had a map out for subscribers since Sat morning but will have one tomorrow afternoon for all to see. I’ll try and remember to post it in here .

Watches for that heavier stripe in central KY

Josh and I have noticed that the NAO data on WeatherBell is way off. That’s what I was basing my warming trend thoughts on lol! Compared to NOAA data it has been way off. Just a heads up anyone else using it.

When correcting that, definitely going the colder route.

For the Tri-state area:

...WINTER WEATHER ADVISORY IN EFFECT FROM 4 AM TUESDAY TO 7 AM EST
WEDNESDAY...

* WHAT...Snow expected. Total snow accumulations between 1 and 3
inches.

* WHERE...Portions of southeast Indiana, northern Kentucky, and
south central and southwest Ohio.

* WHEN...From 4 AM Tuesday to 7 AM EST Wednesday.

The boys had this to say:

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
Surface high pressure will quickly exit the Ohio Valley tonight
as it drifts towards the Atlantic coast. A surface wave will
traverse the southern part of the CONUS and lead to some
impactful weather across the Ohio Valley, primarily on Tuesday.

Increasing mid level clouds are expected Monday night in
response to the surface wave. Additional moisture will advect
into the region overnight. Eventually, enough saturation will
occur to result in snowfall early Tuesday morning across our
northern KY counties. Accumulating snowfall will continue
through most of the day on Tuesday into Tuesday night, with the
highest accumulations across northern KY and the lower Scioto
Valley.

Models continue to have inconsistencies with the northern extent
of the snowfall, along with overall snow totals. Some CAMs
(such as the HRRR and RAP) are on the low end of snow totals in
our CWA. These models try to mix in a fair amount of rain
Tuesday afternoon, which would certainly undercut snow totals.
However, thermal profiles from soundings would suggest that
snow remains the primary p-type throughout the entire day.
Meteorologically, this would make sense given that ILN is on the
northern extent of the precip shield from this surface wave.
Thus, still need to analyze future model runs to assess the
potential for higher snow amounts, especially in our northern KY
counties as they would be located just north of the transition
zone (where higher snowfall rates would occur).

Given the latest forecast trends, have issued a Winter Storm
Watch for Lewis, Mason and Robertson counties in KY where
totals are approaching (if not slightly exceeding) Warning
criteria. Just north and west, an Advisory has been issued given
the consistent signal in snow totals near or exceeding 2".

Good Morning and see some advisories and watches out for parts of the Ohio Valley. Everything looks good and see no reason to change the forecast. The further northwest you live the less chances of seeing snow and the further south and southeast the highest amounts. These overriding events with weak low pressure but plenty of moisture can have busts on the low side where the snow/rain line ends up. If that line goes back and forth then 2-4 is a good call but if that line stalls for several hours you can see a random 6 or 7 inch total. Most likely spot is still from Dry Ridge to Georgetown,Ky. Local I-275 and 1-2 seems good though some totals could get closer to 3 inches especially further south.

The next system comes in quickly and precip again by later Wednesday. This has a stronger low so the push of warmer air will keep us locally mainly rain though you could start out with a little snow or sleet but change to rain quickly. Still somebody in the Ohio Valley could get some ice and heavier snow well to our north and northwest. Thursday morning could end as snow but little if any accumulation as the system moves in and out rather quickly

Storm number 3 for the weekend. Models still showing a mainly rain outcome and very possible though I believe there is more cold around than the models are showing this far in advance. Is that enough though to bring in some other types of precip. Maybe sounds good at this point and the NWS has us in the mid-upper 40's and I believe that is way to high and going more towards the 40 degree mark. Will watch this but at the moment rain but if the colder air is stronger then we are talking some mixing issues.

Good morning Tim! Love the post and you have us covered nicely! Just waiting for some new data to see if the call for Tues needs to be tweaked or not.

No changes from me , time for now casting

tron777 wrote: ↑Mon Feb 10, 2025 5:55 am Good morning Tim! Love the post and you have us covered nicely! Just waiting for some new data to see if the call for Tues needs to be tweaked or not.

Good Morning Les and tons to go over with 3 storms. We are lucky to be even talking about winter weather as we are in phase 7 of the mjo which is normally a rather mild time and yes south of here very mild. The saving part is the AO getting very negative and when you see places like Montana and North Dakota getting extreme cold warning we no its cold. I still believe some of that cold will be here next week and no not expecting the temps they have but several degrees below normal and if we can continue to see energy chances for more snow goes up.

Will be fun to see the models today especially short term as they are not all aligned up with some having a warmer atmosphere and some lower and some higher with total precip. Want to see where that heavier band sets up on Tuesday as well. Going to be a heavy wet snow so the trees will look beautiful.

Bgoney wrote: ↑Mon Feb 10, 2025 6:03 am No changes from me , time for now casting

I agree. A general 1-3" across the area looks good. 3"+ in our southern counties. If these northern solutions are right, then they will be in WSW criteria which is 4"+. I think CVG will end up in that 1-2" range for the most part. (Unless we get another bump of course)

Per the SPC mesopage, the big high over S Canada is only at 1044 MB. Models had this high in the 1050s which is clearly wrong. A lot of the models weaken the high into the 1040s as the day goes on but it's already at 1044 MB so models continue to be too strong with that incoming high IMO. I just thought that it was interesting, that's all. Might be nothing but I think seeing how these features are when compared to the models is very important.

tron777 wrote: ↑Mon Feb 10, 2025 6:23 am Per the SPC mesopage, the big high over S Canada is only at 1044 MB. Models had this high in the 1050s which is clearly wrong. A lot of the models weaken the high into the 1040s as the day goes on but it's already at 1044 MB so models continue to be too strong with that incoming high IMO. I just thought that it was interesting, that's all. Might be nothing but I think seeing how these features are when compared to the models is very important.

Great Post Les and what I saw over the last few days was models showing highs in the 1050's but dropping it quickly to the 1030's. Those minor details can make a difference and not sure if this will but its always in the back of your mind

Looking at the system number 2 and the gfs and euro are different in regards to strength and yes position of the low pressure. Gfs not as strong and low further southeast. Euro well to our west and stronger the CMC even stronger but not as far west as the Euro. I always thought the Euro had the best handle on this system but when you get some snow cover before hand this can tend to push the second system a little further southeast. No matter which solution its mainly rain though if the gfs solution were to happen more mixing issues locally

6Z Euro has 0.20" for QPF at CVG for tomorrow.

tpweather wrote: ↑Mon Feb 10, 2025 6:40 am Looking at the system number 2 and the gfs and euro are different in regards to strength and yes position of the low pressure. Gfs not as strong and low further southeast. Euro well to our west and stronger the CMC even stronger but not as far west as the Euro. I always thought the Euro had the best handle on this system but when you get some snow cover before hand this can tend to push the second system a little further southeast. No matter which solution its mainly rain though if the gfs solution were to happen more mixing issues locally

I'm waiting to see how much snow we get tomorrow. Then, can we briefly start out as a mix before going over to rain for system #2, is the question in my mind.

tron777 wrote: ↑Mon Feb 10, 2025 6:55 am

tpweather wrote: ↑Mon Feb 10, 2025 6:40 am Looking at the system number 2 and the gfs and euro are different in regards to strength and yes position of the low pressure. Gfs not as strong and low further southeast. Euro well to our west and stronger the CMC even stronger but not as far west as the Euro. I always thought the Euro had the best handle on this system but when you get some snow cover before hand this can tend to push the second system a little further southeast. No matter which solution its mainly rain though if the gfs solution were to happen more mixing issues locally

I'm waiting to see how much snow we get tomorrow. Then, can we briefly start out as a mix before going over to rain for system #2, is the question in my mind.

I believe we may have that brief period early on as mix but change to rain but if the gfs happened to be correct we could have a little more winter action on the back side of the system. At this point still like the Euro and with a stronger system to our west this will no doubt bring warm weather higher up and though we may stay in the 30's for most of the storm but liquid more likely. That is why somewhere in the Ohio Valley I believe frz/rain could be an issue and this would be I-70 and northwest towards Indy.