Pre-Christmas (Dec 21-23rd) Winter Storm

[mimillman]

Just now, weathafella said:

Qpf seems more paltry than I would expect.  Trying to figure it out…

It’s the Midwest. We don’t got your style 

[Stevo6899]

17 minutes ago, Chicago WX said:

18z RGEM goes through Indiana. Solid hit for many. Nothing extreme, but solid.

Not a bad run for semi as well with the wraparound and blizzard conditions. Will be fun to see when exactly this things matures and strenghthens. Dont see them blow up overhead around these parts like this, atleast in the eastern lakes.

[Chicago Storm]

4 minutes ago, weathafella said:

Qpf seems more paltry than I would expect.  Trying to figure it out…

Unfortunately the Gulf feed is not the best, due the the wave moving through the Deep South/Gulf Coast over the next few days.

[Powerball]

3 minutes ago, Stevo6899 said:

Not a bad run for semi as well with the wraparound and blizzard conditions. Will be fun to see when exactly this things matures and strenghthens. Dont see them blow up overhead around these parts like this, atleast in the eastern lakes.

How can you tell when the RGEM only goes through 84hr? 

[Malacka11]

I know a few people (Stebo, RC) already commented on the wraparound snow and its effects on overall totals, but I can't help but keep thinking about that. On the latest GFS run, for example, literally half of my total comes from that feature, and I'm rather worried that it goes to shit during nowcasting or something. 

[A-L-E-K]

feels like most recent dogs have have strong ne winds but this is just calm to ripping out of the nw, weird look imo

[SchaumburgStormer]

With the talk of 10:1 being underdone, this will do. 

[ChiTownSnow]

5 minutes ago, Malacka11 said:

I know a few people (Stebo, RC) already commented on the wraparound snow and its effects on overall totals, but I can't help but keep thinking about that. On the latest GFS run, for example, literally half of my total comes from that feature, and I'm rather worried that it goes to shit during nowcasting or something. 

Agreed.  I don't want any funny business, and then have to hope it verifies.  

But at the same time , if it sits there and maybe takes another lap around I'm cool with that.

 

[Stevo6899]

10 minutes ago, Powerball said:

How can you tell when the RGEM only goes through 84hr? 

https://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

 

I'm always confused because after hr 48, it's supposed to be the Canadian, but always looks diff than the Canadian after 48 hrs. I don't think the Canadian has a 18z run?

[Gino27]

Looks like a real screw over for my area if the GFS gets it's way. Cold comes in too late for changeover, and the backside falls apart.

[Malacka11]

4 minutes ago, ChiTownSnow said:

Agreed.  I don't want any funny business, and then have to hope it verifies.  

But at the same time , if it sits there and maybe takes another lap around I'm cool with that.

 

Right, I just don't want to be lured into a false sense of security 

[SchaumburgStormer]

Map is getting "that look"

 

[ChiTownSnow]

^ sure is.   Let's get those pinks

[RCNYILWX]

Qpf seems more paltry than I would expect.  Trying to figure it out…

It's honestly hard to get huge QPF as snow in this area. To get 1" liquid equivalent in a snow system is pretty high end, if you go by the top 5 Chicago snowstorms posted above and at least GHD I and II had lake enhancement in those totals.

So while the top end QPF amounts have come down since yesterday and there's a meteorological reason for it, it also represents coming down closer to reality. The widespread 2"+ precip. totals from the GFS last night are basically unheard of in this part of the Midwest in a snowstorm, with the exception of the January 1967 blizzard.

[SEIL Dawg]

I’ve been following this hoping for a few inches of snow to set the mood for Christmas, but it looks like I’m on the rain/flash freeze side of this one. I don’t even have a SWS anymore. Good luck to everybody hoping to see flakes and lots of them!

[sbnwx85]

11 minutes ago, ChiTownSnow said:

^ sure is.   Let's get those pinks

Reds*

[Powerball]

24 minutes ago, Stevo6899 said:

https://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

 

I'm always confused because after hr 48, it's supposed to be the Canadian, but always looks diff than the Canadian after 48 hrs. I don't think the Canadian has a 18z run?

The RGEM does have an 18z run, and it only goes to 84hr on Pivotal Weather.

[mississaugasnow]

Environment Canada came out with a pretty strong statement. They don't normally put out special weather statements 4 days in advance 

 

Significant winter storm expected late this week into the holiday weekend.

Precipitation may begin as rain or snow late Thursday before possibly transitioning to rain in many areas early Friday. Temperatures are expected to plummet on Friday leading to a potential flash freeze for locations that receive rainfall. Rapidly falling temperatures will be accompanied by strong to potentially damaging winds along with snow that may be heavy at times. Blizzard conditions are possible late Friday into the weekend for areas downwind of Lake Huron and Georgian Bay.

A multi-day lake effect snow event is expected into the weekend in the wake of the system for locations east of the Great Lakes.

While there is high confidence in a high impact winter storm, the details regarding wind speeds, precipitation types and amounts remain highly uncertain at this time. Please monitor your local forecast and the latest alerts for your area.

Consider altering plans through the holiday weekend as travel conditions may become dangerous. Extensive utility outages are possible. Temperatures Friday night into the weekend will likely be the coldest of the season to date.
 

[frostfern]

30 minutes ago, SchaumburgStormer said:

With the talk of 10:1 being underdone, this will do. 

A lot of what's boosting totals here is lake enhancement.  It's unfortunate the main WAA thump is so far north.

[frostfern]

50 minutes ago, weathafella said:

Qpf seems more paltry than I would expect.  Trying to figure it out…

The main overrunning warm-conveyor is missing the US entirely, unfortunately.  It's hard to squeeze a ton of moisture out of the cold-conveyer wrapping around from the north, but the lakes will help some hopefully.  With such a deepening system there will probably be some intense frontogenesis bands on the back side pulling moisture off the lakes.

[Spartan77]

.LONG TERM...(Thursday night through Monday)
Issued at 241 PM EST Mon Dec 19 2022

High Impact Weather Potential: Large storm system with impactful
weather to northern Michigan possible Friday-Saturday with lake
effect and colder weather behind the departing system.

Long term models are continuing to come together with a storm system
that develops in the central Great Plains and moves into the
southern Great Lakes region. There are still uncertainties in the
exact track of this system, which would have a great impact on p-
type and amounts. The current track would definitely produce snow
with possibly a quick period of a wintry mix on the front side
Friday over northern Michigan...but as stated already...still quite
a bit of uncertainty. The storm at this time is forecast to drop
between 27-31mb (depending on model) to become a 967-969mb surface
low in a 24 hour period from Thursday night to Friday night. This is
considerable strengthening (bombogenesis) as it is tracks over/near
the Detroit area and up Lake Huron. This will end up being quite a
storm wherever it impacts, with heavy accumulating and blowing snow
and strong winds in the heart of the storm. Wind will be very
strong...the GFS has the strongest wind gusts...which has hit
hurricane strength along the Lake Michigan shoreline the past four
runs. Regardless of this storm system`s track being either more
north, south, east, or west this will be a very impactful storm to
northern Michigan...possibly historic. It`s also safe to say that
much colder air would move in behind the departing system by the end
of the work week producing lake effect snow at times and some single
digit lows behind this departing storm system.

 

Gaylord has very strong wording on the wind gusts. Curious if that will translate further down the shoreline. Crazy reading most of these AFD's!

[Stevo6899]

26 minutes ago, Powerball said:

The RGEM does have an 18z run, and it only goes to 84hr on Pivotal Weather.

Yea I am aware. Maybe that link is the extended 18z? Whatever model that link runs after hr 84, it looked decent for semi. It has been somewhat accurate over the years. 

[Kaner88]

One of my favorite memories from GHD I was coming down the stairs on the morning everything was winding down and looking out the backyard - the snow drifts were so widespread and so big, it looked like the all the homes were in some post-apocalyptic, Day After Tomorrow type scene, buried in snow and untouched in years.

Doubt we'll get GHD 1 amounts but the winds will hopefully be enough to replicate that effect. One of the strangest sights I've ever seen in a winter storm, for sure.

[Stebo]

1 hour ago, SchaumburgStormer said:

With the talk of 10:1 being underdone, this will do. 

The 18z GFS would be the stupidest solution possible locally. 

[Kaner88]

For what it's worth, WPC's discussion on model guidance, updated today at 4pm Central.

Quote

...Guidance/Predictability Assessment...

The latest guidance continues to show much better agreement on the expected synoptic scale set-up for the major Eastern U.S. low pressure system. The 00z and 06z runs of the GFS continued to show a slower and slightly farther south track with the main upper low compared to the ECMWF, CMC, and UKMET, but the new 12z GFS run (available after forecaster generation time) came much more in line with the consensus. There also remain some track/placement differences on the upper and surface lows as they track northward into Canada. Some timing/amplitude differences, but the guidance also seems to have a better handle on a shortwave tracking from the Southwest to the Gulf Coast as well this weekend. For both, a general model compromise seemed to work well as a starting point for the updated WPC forecast. Another shortwave riding the top of the Western U.S. ridge showed plenty of uncertainty around Sunday-Monday regarding amplification over the central U.S.. Again, the main outlier here was a much weaker 06z GFS, but the 12z looks better. A blend of the ECMWF, CMC, with the ensemble means worked well for this system. Overall, needed changes to the previous WPC forecast were minimal.

 

[sbnwx85]

I have yet to cover a true blizzard while working in TV news. We’re already asking crews who were off Friday to come into work. I usually work 1 pm to 10 pm, but I have a feeling I’ll be starting my Friday much earlier and ending it sometime late on Saturday.

[cyclone77]

Early guess here is for 4-6".  Gonna be tough to measure due to the strong winds and the dry nature of the snow.  Gonna have to dress up like an eskimo to go out and remove the snow lol

[Sciascia]

Catching up from 1:50pm - now as I work 2-10 weeknights…Izzi with one helluva write-up (even if a little premature).

[jlauderdal]

For what it's worth, WPC's discussion on model guidance, updated today at 4pm Central.

...Guidance/Predictability Assessment...
The latest guidance continues to show much better agreement on the expected synoptic scale set-up for the major Eastern U.S. low pressure system. The 00z and 06z runs of the GFS continued to show a slower and slightly farther south track with the main upper low compared to the ECMWF, CMC, and UKMET, but the new 12z GFS run (available after forecaster generation time) came much more in line with the consensus. There also remain some track/placement differences on the upper and surface lows as they track northward into Canada. Some timing/amplitude differences, but the guidance also seems to have a better handle on a shortwave tracking from the Southwest to the Gulf Coast as well this weekend. For both, a general model compromise seemed to work well as a starting point for the updated WPC forecast. Another shortwave riding the top of the Western U.S. ridge showed plenty of uncertainty around Sunday-Monday regarding amplification over the central U.S.. Again, the main outlier here was a much weaker 06z GFS, but the 12z looks better. A blend of the ECMWF, CMC, with the ensemble means worked well for this system. Overall, needed changes to the previous WPC forecast were minimal.

 
The blend is finally in control...i thought a track could be nailed tomorrow night but tomorrow morning looking realistic..i think we see a nudge to the east, SW lower michigan looks real good right now

[Baum]

a taste of AFD's for shits and gigggles:

Minny:

IN SUMMARY, THIS IS SHAPING UP TO BE A HIGH END, LIFE-THREATENING   
EVENT. THE RISK FOR BLIZZARD CONDITIONS HAS INCREASED ACROSS THE   
ENTIRE REGION, EVENT THE EASTERN MINNESOTA AND WESTERN WISCONSIN   
COUNTIES THAT ARE MORE WOODED. THIS, TOGETHER WITH THE EXTREMELY   
COLD WIND CHILLS, NEEDS TO BE TAKEN SERIOUSLY.

 

Beer Town:

CONFIDENCE CONTINUES TO INCREASE IN A POTENT WINTER STORM LATER  
THIS WEEK THAT COULD BRING BLIZZARD CONDITIONS TO SOUTHERN  
WISCONSIN.

Des Moines:

TRAVEL ACROSS MUCH OF CENTRAL IOWA IS LIKELY TO BECOME   
DANGEROUS IF NOT IMPOSSIBLE IN SOME LOCATIONS IN IOWA BY LATER   
THURSDAY INTO FRIDAY. IN ADDITION, ANYONE STRANDED WILL BE FACED   
WITH LIFE THREATENING CONDITIONS IF CAUGHT OUTDOORS GIVEN THE   
EXTREMELY COLD WIND CHILLS, POOR VISIBILITIES AND DRIFTING SNOWPACK.   
ACCORDINGLY, THE WINTER STORM WATCH HAS BEEN UPDATED WITH BLIZZARD   
WORDING.  

Kansas City:

TRAVEL THURSDAY AND FRIDAY STRONGLY DISCOURAGED WITH POTENTIAL   
  WHITE-OUT/BLIZZARD CONDITIONS 

Fort Wayne:

HOW QUICKLY THIS DEEPENING AND EVENTUAL WARM OCCLUSION OCCURS IS   
THE KEY TO THE ALL IMPORTANT SFC LOW TRACK AND WHO ENDS UP TAKING A   
DIRECT HIT FROM A CRIPPLING BLIZZARD. EVEN AREAS THAT DON'T TAKE A   
DIRECT HIT, WHICH COULD INCLUDE A LOT OF THE IWX CWA, WILL STILL   
SEE SUBSTANTIAL IMPACTS TO BE DISCUSSED SOON.

 

Merry Christmas.