Absolute Vorticity

18Z Euro probably gives IND 0.50 to 0.60" of backside snows! Wow.... what a storm we have coming regardless of how much snow we actually see. That message we must continue to drive home. We don't get intense low pressures often in the Lakes / OV like they do for those Nor 'Easters. I'm telling you guys and you should know this already, get prepared NOW if you haven't. Tomorrow no problems! Even Thursday with a little bit of rain no problems. Sometime Thurs evening on... we've got problems! So that's your window to get ready!

tron777 wrote: ↑Tue Dec 20, 2022 8:41 pm 18Z Euro probably gives IND 0.50 to 0.60" of backside snows! Wow.... what a storm we have coming regardless of how much snow we actually see. That message we must continue to drive home. We don't get intense low pressures often in the Lakes / OV like they do for those Nor 'Easters. I'm telling you guys and you should know this already, get prepared NOW if you haven't. Tomorrow no problems! Even Thursday with a little bit of rain no problems. Sometime Thurs evening on... we've got problems! So that's your window to get ready!

Exactly Les and I sent out my forecast to my neighbors this evening and told them don't worry about the snow totals because even a little snow is going to cause problems and wind chills getting to maybe -30. No doubt power outages will happen but lets hope they are not widespread. Roads on Friday are going to be bad and I believe we will see some level 2 or 3 in many counties on Friday. Getting a normal 2-5 inch snow with temps in the upper 20's is rather easy to handle especially once the road crews get done but this go around the road crews may be fighting tons of ice an blowing snow and with temps probably making it to around 7 degrees on Friday its going to be brutal.

21Z SREF is in.... the average has increased as you would expect. For CVG, the mean is around 3" now. Seeing less members now under the 1" category and the biggest cluster of members is now grouped in the 2-5" range. Other mean totals...

HAO and ILN - 3.3"
MGY - 3.7"
DAY - 4"
CMH - 3"
Sidney, OH 4.2"

tpweather wrote: ↑Tue Dec 20, 2022 8:46 pm

tron777 wrote: ↑Tue Dec 20, 2022 8:41 pm 18Z Euro probably gives IND 0.50 to 0.60" of backside snows! Wow.... what a storm we have coming regardless of how much snow we actually see. That message we must continue to drive home. We don't get intense low pressures often in the Lakes / OV like they do for those Nor 'Easters. I'm telling you guys and you should know this already, get prepared NOW if you haven't. Tomorrow no problems! Even Thursday with a little bit of rain no problems. Sometime Thurs evening on... we've got problems! So that's your window to get ready!

Exactly Les and I sent out my forecast to my neighbors this evening and told them don't worry about the snow totals because even a little snow is going to cause problems and wind chills getting to maybe -30. No doubt power outages will happen but lets hope they are not widespread. Roads on Friday are going to be bad and I believe we will see some level 2 or 3 in many counties on Friday. Getting a normal 2-5 inch snow with temps in the upper 20's is rather easy to handle especially once the road crews get done but this go around the road crews may be fighting tons of ice an blowing snow and with temps probably making it to around 7 degrees on Friday its going to be brutal.

Strongly agree.... great post!!!

I think I'll stay up for the 0Z NAM and crack open a beer!

tron777 wrote: ↑Tue Dec 20, 2022 8:48 pm 21Z SREF is in.... the average has increased as you would expect. For CVG, the mean is around 3" now. Seeing less members now under the 1" category and the biggest cluster of members is now grouped in the 2-5" range. Other mean totals...

HAO and ILN - 3.3"
MGY - 3.7"
DAY - 4"
CMH - 3"
Sidney, OH 4.2"

Good to see Les and you look across the broad in the northern and central plains into the Ohio Valley we are seeing more sites with this range. Yesterday the range was to high imo across Iowa,Illinois and Missouri but they are coming back down to reality.

CB's evening update. Good luck trying to get it to load. His site is down more then it's up. Keep hitting F5. As Matt said earlier and CB said it himself the other day... he put more money into the server to keep it from crashing. Someone got ripped off!

https://kyweathercenter.com/?p=56972

EDIT: Here's his first call map in case the article doesn't load for you.

Just taking a peak at the 0Z HRRR which only goes out to 48 hours. You wanna talk about a slap in the face that is coming! So per this model, here we are at 7pm Thurs evening. 43 here, 11 in Western IN and below zero already in ILL. Googly Moogly! This is going to sting!

WOW! 0Z NAM has a 1069 MB high in MT at 39 hours. Record breaking cold coming into the country folks! This is truly historic cold coming to some places especially in the Rockies, N plains, Upper Midwest regions.

EDIT: Lows in the -40s and -50s and with wind chills -80s! That's what some of these regions will see. This is truly a Siberian airmass as wicked as they come!

I have an aunt and cousin on Dad's side of the family who reside in Baldwin!

Winter Storm Watch

URGENT - WINTER WEATHER MESSAGE
National Weather Service Grand Rapids MI
331 PM EST Tue Dec 20 2022

MIZ037>040-043>046-050>052-056>059-064>067-071>074-210445-
/O.NEW.KGRR.WS.A.0005.221222T2100Z-221225T0000Z/
Mason-Lake-Osceola-Clare-Oceana-Newaygo-Mecosta-Isabella-Muskegon-
Montcalm-Gratiot-Ottawa-Kent-Ionia-Clinton-Allegan-Barry-Eaton-
Ingham-Van Buren-Kalamazoo-Calhoun-Jackson-
Including the cities of Ludington, Baldwin, Reed City, Clare,
Hart, Fremont, Big Rapids, Mount Pleasant, Muskegon, Greenville,
Alma, Grand Haven, Jenison, Grand Rapids, Ionia, St. Johns,
Holland, Hastings, Charlotte, Lansing, South Haven, Kalamazoo,
Battle Creek, and Jackson
331 PM EST Tue Dec 20 2022

...WINTER STORM WATCH IN EFFECT FROM THURSDAY AFTERNOON THROUGH
SATURDAY EVENING...

* WHAT...Blizzard conditions possible. Total snow accumulations of
8 to 17 inches possible through Friday. Winds could gust as high
as 55 mph and will cause significant blowing and drifting snow.
Additional heavy snow and high winds are expected into Saturday
with storm total snowfall possibly reaching 2 feet along and
west of US 131 from Kalamazoo northward to Grand Rapids and up
into Big Rapids.

* WHERE...Portions of central, south central, southwest and west
central Michigan.

* WHEN...From Thursday afternoon through Saturday evening.

* IMPACTS...Travel could be very difficult to impossible. Areas of
blowing snow could significantly reduce visibility. The
hazardous conditions will impact the commutes and holiday
travel. Strong winds could cause tree damage leading to power
outages. Subzero wind chills are expected Friday into Saturday.

* ADDITIONAL DETAILS...Snow will develop Thursday afternoon and
evening. It will become heavy at times Thursday night. The risk
for heavy snow will persist through Friday. The widespread snow
will become more lake effect Friday night into Saturday with the
heaviest accumulating snow expected to shift closer to the
lakeshore. The strongest winds are expected Friday into Friday
evening. Snowfall rates of an inch per hour are expected. The
temperature will be falling from around freezing Thursday
afternoon...into the 20s for Thursday night with increasing
impacts expected on the roadways then.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare for possible blizzard conditions. Continue to monitor the
latest forecasts for updates on this potentially dangerous situation.

&&

$$

young pup wrote: ↑Tue Dec 20, 2022 9:26 pm 606D5704-81D6-4E35-903F-8663B4D4C939.jpeg

tron777 wrote: ↑Tue Dec 20, 2022 9:31 pm

young pup wrote: ↑Tue Dec 20, 2022 9:26 pm 606D5704-81D6-4E35-903F-8663B4D4C939.jpeg

ChristmasVacation.gif

lol

CVG gets about 0.15 of rain then we flip to snow. Western counties changeover around 10pm. Probably 11pm-1am for CVG Land and after midnight to 2am in the East. Once you changeover, it'll literally be hammer time for a few hours. A shame we can't get a 12 hour period of snow. NAM does try and form a weak low along the East Coast but we still get that more northern track. NAM was a tad weaker SE from its 18Z run but not remarkedly so. CVG still gets 0.20" that falls as snow.

So in summation...

Light rain Thurs afternoon changing to snow Thurs evening from West to East across the area. VERY FAST temp drop. Winds start to pick up immediately behind the frontal passage. Flash freeze likely! Several inches of snow possible. Amounts TBD... a general modeled range of 2-5" being shown across the region. Winds gusting 40-50 mph likely later Thurs night all day Fri into Friday night. Gusts to 30 mph Christmas Eve. Further calming down on Christmas Day. Temp wise... low to mid 40s ahead of the front. You crash behind the front all the way down to 0 Fri morning if not a touch below. We stay in the single digits on Friday. 10 above TOPS! Go down to 0 Fri night if not below in some areas. The deeper the snowpack, the colder you get. Christmas Eve, highs around 10. That night -5 to 5 above. Christmas Day, maybe around 20 with lows 5 to 10 above. Hope you're ready for this especially if you lose power!!! Can't stress the power issue enough folks! Please take this system seriously whether you get 1" of snow or 6"+ in your backyards. The snow part truly is secondary to all of the other hazards.

Ok, my PSA is over. Good night, please keep the discussion going, and I'll catch up in the morning.

Good Evening and my last post of the day and most likely by Wednesday morning we will have all of Ohio and Kentucky included in the winter storm watch. By late Wednesday or very early Thursday many areas will become winter storm warnings and some with winter weather advisories plus wind chill warnings as well. Go to fun the next 72 hours at least and hopefully everyone remains safe and power stays on for the entire storm.

The gfs looks to have a very intense band of snow with it as moves in and out with the frontal passage. With some wrap around snow showers into Friday evening.

Can’t say I fully agree with the map but 1-2,2-3 is likely

mikeyp wrote: ↑Wed Dec 21, 2022 6:17 am Can’t say I fully agree with the map but 1-2,2-3 is likely
80F6ECAA-F4EC-4469-84E4-60264B0B2C63.png

I believe that map will prove to be underdone. These maps they come out with ALWAYS change. It will be adjusted throughout the day.

Good Morning and I really thought a winter storm watch would have been issued this morning. I believe in caution when issuing watches and warnings but this is not just about snow totals. Ice with the flash freeze and strong winds along with the snow that falls will cause many travel issues. One other reason is the time of year and 2 days before Christmas many folks are out and about and this should add into the forecast. No I don't like the sky is falling but when the weather outside is something we have not had this year and a storm that is feature more by the cold and wind I believe a watch is a good ideal. Then on Thursday when we have the latest data you can move to a winter storm warning or maybe a winter weather advisory and wind chill advisory. Enough of the rant and overnight some models went down in snow totals and others went up and they keep switching which areas will get the most snow. Models are just having a hard time with this kind of cold and the timing and location of the low closing off. Still like the 2-5 inches and this will be done in a short period of time in the neighborhood of 4-6 hours behind the front. The remainder of Friday will be the winds and wind chills nearing -30 at times. Do I expect the models to continue to switch with amounts and areas with the heaviest snows and the answer is yes. Yes we have had arctic fronts come through here with light snows in the past and you get an inch or so as that is just the lift with the front. This time we have a piece of energy attached to the front and with a very strong jet later on Thursday into the day Friday plus a true cross-polar arctic outbreak as temps of -60 in the Yukon there will be problems on Friday. Going to be so many cars that don't start and my gut tells me tons of accidents as I believe the flash freeze means business.

Great post Tim, nothing to add to effects of the storm. Still like 1-3 range for the Av land triangle cvg, Day, Cbus with iso 4 in an arc from SE Indiana counties to near Dayton. Reasons are the same as mentioned yesterday. Nice ratios of course, say 25 to 1 , but I'm figuring the winds negate that down to about half that say 13 to 1 and thats a total guess . I'm also figuring about .15- .25 , maybe .30" at best post frontal Qpf.

Bgoney we are on the same page. The winds and how that can negate totals is one you mentioned and I agree that is a big part of the forecast. I was just not sure how to figure out the ratio and you may be dead on with the 13-1 and it may be 17-1 or something different and I really had a hard time figuring that out.

tpweather wrote: ↑Wed Dec 21, 2022 8:06 am Bgoney we are on the same page. The winds and how that can negate totals is one you mentioned and I agree that is a big part of the forecast. I was just not sure how to figure out the ratio and you may be dead on with the 13-1 and it may be 17-1 or something different and I really had a hard time figuring that out.

Last year's February storm, I had 2" on 90% of my yard but 4ft drift on the fence opposite of the wind direction. So much wind up here around my place in the country. I have food that I can cook on my fire and a stack of wood. Wind and refreeze are going to be the worst parts of the storm.

Good morning all and all I can say is WOW @ the 0Z GFS. This storm bombs out to 959 MB on this run, the strongest I've seen yet. I have no idea if that is overdone or not, but sheesh! You just don't see that kind of storm every day in the Lakes region. 6Z GFS was at 960 MB so very close! Euro is in the mid 960s! Still very intense. I don't really have much else to say either. I think we've got the timing covered pretty well. Rain Thurs afternoon changing to snow with the frontal passage in that 7-9pm window in the West and after midnight to 2am out East. 9-11pm is good for CVG Land. Things go downhill within hours of the frontal passage with a 2-4 hour period of mod to heavy snow. Then lighter snows thru Fri morning excepted. They will last longer the further north you go on Friday esp folks North of I-70. I like that 1-4" range still for our local area. 2-3" is a nice call for CVG Land being right in the middle. I think we will have 0.20-0.30" of backside precip to play with for snowfall accumulations. Add it gusts in the 40-50 mph range and you've got a classic good ole fashioned blizzard / snow storm on your hands. Flash freeze as we've said is likely! Mid 40s to zero in an 8 hour period. Wow! We could really use more of a southerly bump in the track. This is probably about as far East as it's going to get. We'll see with today's runs. Fully sampled now.

Time for some nowcasting... SPC mesopage shows our storm, which is currently a 1010 MB low in Central Idaho. Pressure falls suggest that this thing will be dropping down the Rockies and into the OK / TX Panhandle area later. The further south this thing goes before lifting NE, the better off we'll be. I'd like to see it dig deeper into Texas, so that's one of things I will be watching today.