Pre-Christmas Storm Plains/MW/GL 12/21-12/22

[Clinton]

3 minutes ago, winterfreak said:

Chicago gets 18-24 though. Jealous…

Thats part of living where we live lol!

[jaster220]

1 minute ago, Clinton said:

About a 100 miles further west and it was stronger as it moved south of me like the GFS.  Lets hope both trends continue.

Haha, I need a positive trend too amigo (noticeably absent is @Niko)

Overnight pre-18/12z worse runs for DTX, but their write-up is very well done. Worth reading for those in The Mitt.

Attention over the coming days will remain fixed upon the storm
system that is forecasted to impact the upper Midwest/Great Lakes
region during the holiday travel period of the 12/21 - 12 /23.
Attention will also be given to the arctic cold over the Christmas
holiday 12/24 - 12/26. With no real surprises or drastic changes
amongst the 18.00Z deterministic solutions, confidence is rapidly
increasing in a significant winter storm system impacting portion(s)
of the state during the middle to end of the week. Important to
stress here at the outset that given the envelope of potential
solutions, especially the well organized/relatively warm occlusion
in the control run of the ECMWF, details (i.e...precipitation type,
precipitation rate, precipitation amounts, high wind potential) will
absolutely matter and very much determine what sensible weather
impacts Southeast Michigan and your particular backyard will
observe. So while confidence is now reasonably high that impactful
weather will occur over Southeast Michigan (no real null case to be
found in the NWP), whether or not the cwa will take a direct hit
remains unknown at this time. So rather than provide a discussion on
precipitation type and amounts for a Day 5 and Day 6 system, would
like to offer one on the predictability of the system and the
differences between the GFS deterministic and ECMWF/Canadian GEM
solutions.

Great model agreement exists that a strong +175 upper level jet
packet will carve/dig into the Northwest United States Tuesday and
Wednesday. Very obvious and noteworthy in how well this jet exit
region is linked to and in tandem with Potential Vorticity trough
axis over northern Canada shortly after it arrives. Models then show
a significant portion of the PV reservoir being drawn into and
phasing into the basal portion of the trough as the upper level jet
digs into the central United States. The first big difference
between the ECMWF and GFS solutions is how fast/progressive the left
exit region dynamics remains. The ECMWF is the faster of the two
solution camps with the exit region pushing across all of Arkansas
and into Tennessee by 18Z Thursday. The GFS solution is slower and
less progressive still digging across the OK panhandle at the same
time 18Z Thursday. The big thing to note in the ECMWF is just how
well the wavelengths of the left exit region and the whole western
half of the Canadian PV reservoir match up. This allows for a much
more negative tilt, earlier, and very rapid phasing/deepening low
pressure system over portions of IN Thursday night. The net result
there is an almost instant occlusion over Southeast Michigan which
preserves just enough of the preceding mild and warm air at the
surface to really factor in on precipitation types. The GFS is
slower with the jet exit region, allows for greatest low deepening
rates over Ohio and brings more of a classic snow track for
Southeast Michigan through central Ohio. Interestingly enough, the
Canadian GEM shows more similarities to the ECMWF with the
orphaned occlusion, but is a compromise thermally to the colder GFS.

So until the timing of this jet exit region gets resolved, there
will remain uncertainty to the details of the event. From the 17.12Z
GEFS data, 41% percent of the variability at Day 5 could be
explained by the timing of the trough/ridge couplet. As a note, EOF1
of 24 hour mean 500 height was showing a dipole mean height
difference of some 100m. One usually does not see a magnitude this
great in this technique. Given this mean height anomaly difference,
its going to take a few ensemble cycles/days to improve confidence
on forecast timing. The upper level jet exit region of particular
interest is not forecasted to push onshore of the PACNW until 00Z
Wednesday. Cluster phase space actually showed a better than usual
integration at Day 5 of the CMCE/GEFS/EPS, but need to stress
separation does exist between GEFS and EPS. Cant say with any
certainty which of the solution camps or timing is going to verify,
however, will say its difficult to imagine the phasing of the large
PV reservoir and cyclonically curved jet exit region occurring as
cleanly as these ECMWF solutions have been.

The bottom line is its way too early to provide a discussion on
precipitation type and amounts. Again with no null case in the
deterministic solutions, measurable amounts amongst virtually all of
the EPS members and a majority of the GEFS, its difficult to
envision a failure point to a regional winter storm system. Of
particular interest in the upcoming data is what the high wind
potential will be. The combination of very strong kinematic fields
with a fresh arctic cold air mass is a recipe for a high impact wind
event. The combination of very strong winds with falling snow could
make travel virtually impossible for some part(s) of the region in
the lead up to the holiday. Any power outages ahead of the projected
cold next weekend would be very tough.

[Madtown]

Gut says this heads a bit more NW. same thing happened to the last one. Souix falls went from money to too far south. I was golden and ended up too far east. Just my thoughts.

[jaster220]

1 minute ago, Hoosier said:

The snow + wind combo on the 12z Euro is the most extreme model run I have ever seen in my life for my backyard for a storm that is within 5 days.

And DTX has noted in their AFD that (as I have called model bs on b4) its portrayal is almost "too perfect" for reality. Obviously time will tell, but these models are notoriously tweaked to max conditions. 

[winterfreak]

10 minutes ago, Clinton said:

Thats part of living where we live lol!

I know! I want what they have lol.

[Money]

Euro has 50+ mph gusts in eastern WI and N IL for 24+ hours 

[Clinton]

6 minutes ago, jaster220 said:

Haha, I need a positive trend too amigo (noticeably absent is @Niko)

Overnight pre-18/12z worse runs for DTX, but their write-up is very well done. Worth reading for those in The Mitt.

Attention over the coming days will remain fixed upon the storm
system that is forecasted to impact the upper Midwest/Great Lakes
region during the holiday travel period of the 12/21 - 12 /23.
Attention will also be given to the arctic cold over the Christmas
holiday 12/24 - 12/26. With no real surprises or drastic changes
amongst the 18.00Z deterministic solutions, confidence is rapidly
increasing in a significant winter storm system impacting portion(s)
of the state during the middle to end of the week. Important to
stress here at the outset that given the envelope of potential
solutions, especially the well organized/relatively warm occlusion
in the control run of the ECMWF, details (i.e...precipitation type,
precipitation rate, precipitation amounts, high wind potential) will
absolutely matter and very much determine what sensible weather
impacts Southeast Michigan and your particular backyard will
observe. So while confidence is now reasonably high that impactful
weather will occur over Southeast Michigan (no real null case to be
found in the NWP), whether or not the cwa will take a direct hit
remains unknown at this time. So rather than provide a discussion on
precipitation type and amounts for a Day 5 and Day 6 system, would
like to offer one on the predictability of the system and the
differences between the GFS deterministic and ECMWF/Canadian GEM
solutions.

Great model agreement exists that a strong +175 upper level jet
packet will carve/dig into the Northwest United States Tuesday and
Wednesday. Very obvious and noteworthy in how well this jet exit
region is linked to and in tandem with Potential Vorticity trough
axis over northern Canada shortly after it arrives. Models then show
a significant portion of the PV reservoir being drawn into and
phasing into the basal portion of the trough as the upper level jet
digs into the central United States. The first big difference
between the ECMWF and GFS solutions is how fast/progressive the left
exit region dynamics remains. The ECMWF is the faster of the two
solution camps with the exit region pushing across all of Arkansas
and into Tennessee by 18Z Thursday. The GFS solution is slower and
less progressive still digging across the OK panhandle at the same
time 18Z Thursday. The big thing to note in the ECMWF is just how
well the wavelengths of the left exit region and the whole western
half of the Canadian PV reservoir match up. This allows for a much
more negative tilt, earlier, and very rapid phasing/deepening low
pressure system over portions of IN Thursday night. The net result
there is an almost instant occlusion over Southeast Michigan which
preserves just enough of the preceding mild and warm air at the
surface to really factor in on precipitation types. The GFS is
slower with the jet exit region, allows for greatest low deepening
rates over Ohio and brings more of a classic snow track for
Southeast Michigan through central Ohio. Interestingly enough, the
Canadian GEM shows more similarities to the ECMWF with the
orphaned occlusion, but is a compromise thermally to the colder GFS.

So until the timing of this jet exit region gets resolved, there
will remain uncertainty to the details of the event. From the 17.12Z
GEFS data, 41% percent of the variability at Day 5 could be
explained by the timing of the trough/ridge couplet. As a note, EOF1
of 24 hour mean 500 height was showing a dipole mean height
difference of some 100m. One usually does not see a magnitude this
great in this technique. Given this mean height anomaly difference,
its going to take a few ensemble cycles/days to improve confidence
on forecast timing. The upper level jet exit region of particular
interest is not forecasted to push onshore of the PACNW until 00Z
Wednesday. Cluster phase space actually showed a better than usual
integration at Day 5 of the CMCE/GEFS/EPS, but need to stress
separation does exist between GEFS and EPS. Cant say with any
certainty which of the solution camps or timing is going to verify,
however, will say its difficult to imagine the phasing of the large
PV reservoir and cyclonically curved jet exit region occurring as
cleanly as these ECMWF solutions have been.

The bottom line is its way too early to provide a discussion on
precipitation type and amounts. Again with no null case in the
deterministic solutions, measurable amounts amongst virtually all of
the EPS members and a majority of the GEFS, its difficult to
envision a failure point to a regional winter storm system. Of
particular interest in the upcoming data is what the high wind
potential will be. The combination of very strong kinematic fields
with a fresh arctic cold air mass is a recipe for a high impact wind
event. The combination of very strong winds with falling snow could
make travel virtually impossible for some part(s) of the region in
the lead up to the holiday. Any power outages ahead of the projected
cold next weekend would be very tough.

Where is Niko last I saw from him he was in NYC.  Even with the west trends the occlusion keeps snow falling and piling up in your back yard.  What's a successful amount for you out of this.  For me I have expected to be in that 4-8 range obviously more would be great but that's a real good snow for KC.  I know that Detroit gets a lot more snow than I do on average so your expectations could be much different.

[Tom]

12z Euro is about as juiced of a run as I've seen them in SW MI...3"+ of liquid fluffed up on the backside of the LOW would be prolific LES...prob similar to what happened to Watertown/Buffalo, NY back in NOV...

 

 

For N IL peeps, it begins really snowing at midnight on the EVE of Christmas Eve (Friday am) when temps are sub 10F!  That's freakin' cold and would feel like your living in Alaska.  Wild run.

 

[Ottawa CO, MI]

28 minutes ago, Tom said:

12z Euro is about as juiced of a run as I've seen them in SW MI...3"+ of liquid fluffed up on the backside of the LOW would be prolific LES...prob similar to what happened to Watertown/Buffalo, NY back in NOV...

 

 

For N IL peeps, it begins really snowing at midnight on the EVE of Christmas Eve (Friday am) when temps are sub 10F!  That's freakin' cold and would feel like your living in Alaska.  Wild run.

 

It will miss W MI. It always does. My gut says the low passes overhead and we get 4-7 inches of snow while Wisconsin gets buried. 

[gosaints]

Goalposts are still stationed from about MSP from Detroit.  If I was Money I would be prepping for a Christmas wrecker 

[Tom]

12z EPS increased totals all across WI/MN/N IL/N IN/IA and into MI...my interpretation is the model is seeing this storm phase earlier...

 

[bud2380]

To illustrate how far apart the GFS and Euro are with the snow shield.  Here they are at hour 90 with a 24 hour snow map.  

The GFS is WAY further south.

 

 

 

[bud2380]

The differences are even more stark at 102 hours.

 

 

 

 

[indianajohn]

1 hour ago, hawkstwelve said:

Snowy snowy snowy.

A Generational snow storm/blizzard in the making for Chicago/northwest indiana?? Highly unlikely to verify but will a fun one to track this week!!

[Hawkeye]

22 minutes ago, Tom said:

12z EPS increased totals all across WI/MN/N IL/N IN/IA and into MI...my interpretation is the model is seeing this storm phase earlier...

6" in Cedar Rapids is even better than the op.  That gives me hope the op could come farther west.

[Tom]

3 minutes ago, Hawkeye said:

6" in Cedar Rapids is even better than the op.  That gives me hope the op could come farther west.

12z Euro Control shows the .50"qpf farther west...similar to the Euro Op...

 

[Stacsh]

GRR talking rain in the beginning.  Backside weather could be significant.  But blah.  The path over my area would limit this storm.  Sorry @jaster220

[Chambana]

Lots of coffee and emotions over the next few days. The consensus is pretty remarkable given the timeframe. I was screwed in GHD I and GHD II, my last true blizzard was 2-13-07, this one is taking shape to be one for the record books. 
 

I can’t fathom 6-10” with 40-60mph winds and plunging temperatures. Maybe the Polar Vortex Blizzard comes close? 

[Money]

51 minutes ago, gosaints said:

Goalposts are still stationed from about MSP from Detroit.  If I was Money I would be prepping for a Christmas wrecker 

Hard not to get excited at this point but still a good 2 days of model runs before we really start to lock into a solution 

Do like where I sit at this point though but we’ll see 

 

[OKwx2k4]

If euro fades to the GFS solution, while it (gfs) continues evolving in a southerly direction, then this storm is going to be awesome.

That was a great write-up posted. The euro showed snow first this far south and then varied wildly if i recall right. I agree that the euro doesn't look right now. 

[Money]

NAM looks nothing like euro/icon etc at her 84. Looks way slower with the system 

[FV-Mike]

Some Strong wording from LOT this afternoon

All eyes in the long term period are on the late week cyclone and
intrusion of bitterly cold air along with dangerous wind chills
late this week into the weekend.

Confidence continues to steadily increase that a potentially
crippling blizzard could impact portions of the region later this
week, the timing of which couldn`t be worse for holiday travel.
If, and how severely, our forecast area (CWA) will be impacted
depend on the exact track of the cyclone and to some extent the
magnitude and timing of the forecast rapid deepening.

Medium range guidance has been advertising a powerful cyclone
spinning up over the Great Lakes or northeast U.S. for days now,
with a pretty sizable spread in where the storm will
develop/track. There was a cluster of guidance favoring a Great
Lakes target region, which would increase chances for major
impacts in our CWA, with a second cluster favoring the New England
resulting in disruptive, but far less extreme winter weather
locally. Trend in ensemble guidance over the past 48 hours has
been decidedly away from a New England cyclone and toward
cyclogenesis farther west over the Great Lakes with recent runs of
the GFS/GEFS making the significant shift west.

While track guidance has shown (pretty typical) variability, the
theme of rapid, and potentially explosive, deepening of the
cyclone has been a fairly consistent theme in guidance for days
now. The expected intensity of the cyclone combined with the very
strong arctic high (>1040mb) over the northern and central Plains
leads to high confidence in a noteworthy high wind event with this
system.

 

[Money]

18z ICON nearly identical to 12z EURO through HR 90

[winterfreak]

18z ICON. Much better around here…

[jaster220]

2 hours ago, Clinton said:

Where is Niko last I saw from him he was in NYC.  Even with the west trends the occlusion keeps snow falling and piling up in your back yard.  What's a successful amount for you out of this.  For me I have expected to be in that 4-8 range obviously more would be great but that's a real good snow for KC.  I know that Detroit gets a lot more snow than I do on average so your expectations could be much different.

Niko is either too busy to be in here or jet-setting to NYC or Greece is my best guess. Sure he will pop-up whenever he can from wherever. 

Struggling with what to call a success here at my new locale. Have seen Detroit area be nickel-n-dime heaven for the most part with a few notable exceptions like GHD-2 and Jan '99. I think this will play out similar to a Jan '99 storm with the SLP passing to my W and/or N. Huge difference with '99 which delivered on the front end due to pre-storm frigid arctic air that never scoured out and this time I am counting on the backside cold. Backside cold away from a LES zone is a very hard sell from my lifetime around the GL's. As my expectations since moving here have been dashed with every storm, going to shoot low and say 2-5" which due to winds will look half that. 6+ will be pulling a rabbit from the old hat Christmas miracle for this place. DTW, a mere 8 miles south has repeatedly out-scored Canton on every event from last November's clippers to the LES this Nov. Modelling continues that theme if this SLP shoot north of the MI/OH line as it appears it will do. Trying to sit back and enjoy the ride. I'm a bit too quietly competitive for that to work tho, lol. You may miss some of the dynamic fun we get up here, but you stay well N of the track and should be all snow for a beautiful over-due White Christmas. 

[jaster220]

2 hours ago, hawkstwelve said:

Snowy snowy snowy.

Wow. @Tom's Holiday Dream Storm and "build the glacier" tales coming to fruition. Kudos on LR calls and optimism!

[bud2380]

Looking at the 18z NAM, I think you can feel safe to say, the NAM is not going to be useful for this storm until inside 48 hours.  It's so far off the other models right now.  

[Money]

GFS likely will come in father NW than 12z based on what I’m seeing through HR 66. Shifted more towards euro early on 

[CentralNebWeather]

NWS Hastings afternoon disco:

“Now that we have covered wind chill, there is also the snow element to this. There is increasing confidence in at least some snow but amounts are still somewhat uncertain...latest WPC ensemble plumes suggest around 2" to 4" but there are still a few days to nail that down and those numbers could trend either way at this point. Regarding timeframe, latest model guidance indicates this will move in Wednesday morning with the bulk of the snow falling Wednesday evening and overnight, then moving out to the east Thursday morning. With temperatures as cold as they will be, this will be a dry, powdery snow with higher than normal liquid to snow ratios (LSRs). Some of the deterministic models like a ratio in the low 20s:1, but chose to go a bit lower due to the probability of dendritic fracturing in those strong winds. No matter what the LSR or the snowfall amount, any snow that falls will blow around, and it does not help that those are a couple of the busiest travel days just before Christmas. It is too early to be forecasting "blizzard" conditions especially with uncertain snowfall amounts, but the potential is in our minds as we get closer to this event. Keep in mind if traveling that the combination of blowing snow, poor visibility, and bitter cold wind chills could make travel conditions very dangerous very quickly.”

 

[Money]

L in SW MO at 99 

[bud2380]

GFS buries all of NE with 6+" of snow.  

[winterfreak]

Low further nw again this run. It’s in NW ARK at 102 hrs…

[bud2380]

GFS 4mb deeper through 108 hours and slightly further NW.  

[jaster220]

3 hours ago, Hoosier said:

The snow + wind combo on the 12z Euro is the most extreme model run I have ever seen in my life for my backyard for a storm that is within 5 days.

3 hours ago, Money said:

Euro has 50+ mph gusts in eastern WI and N IL for 24+ hours 

APX used the "H" word

 

Jan '78, but further N as climo not my friend in Dec. 

[bud2380]

Chicago is gonna get crushed on this run. 

[Money]

Just sits and spins in western IN. Sub 980 Mb

 

IL/MI/EvWI crushed this run 

[winterfreak]

18z GFS. Enjoy…

[bud2380]

GFS has snow ratios in Iowa > 20:1.  I'd be very skeptical of that.  Might need to chop the Kuchera totals by 1/3 to 1/2 in Iowa.  

[bud2380]

Insane totals.  And so so different on the heaviest placement vs. the Euro.  Both show the storm wrapping up into IN and dropping heavy snow into IL and into the GL regions of WI & MI, but the Euro has the initial band of heavier snow much further north into WI and MN, while the GFS hammers areas much further south.  

 

 

[jaster220]

2 hours ago, gosaints said:

Goalposts are still stationed from about MSP from Detroit.  If I was Money I would be prepping for a Christmas wrecker 

Chains are clearly being moved down the field by the Refs. West and west we go..

1 hour ago, Stacsh said:

GRR talking rain in the beginning.  Backside weather could be significant.  But blah.  The path over my area would limit this storm.  Sorry @jaster220

Ha, yeah those Euro maps with feet of SN over SWMI are a joke. How about this. You come over to my place, and I'll take up a mini-vacation at your place, say beginning Wednesday evening. That way you'll get to watch my flood puddles flash freeze. I'm sure it will be so much more entertaining than not seeing your neighbor's place due to zero visibility in ++SN