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

[Jarod]

18 hours ago, jaster220 said:

Weenied your post cuz this no longer on fantasy range maps and ALL regional NWS offices are pretty much acknowledging a major storm in the making. GRR most certainly issued bliz warnings much more recently than GHD-1. Maybe not for Kent or all of their CWA (maybe only happened once in '78), but that Jan '20 event they upgraded a bunch of counties as the follow-on LES on a WSW wind was insane. 

I'm blaming you if this goes west of here. Then again, i have the rest of the year off of work after Tuesday, so maybe I should just temporarily relocate to where ever is supposed to be hit the hardest

[Money]

Euro weaker/east on the 6z run 

[Madtown]

MQT about as close to all in as they ever have been in my 4 years of reading them.

At 00z Thursday, warm air advection overrunning the arctic front
appears to result in a broad area of light to moderate snow.
Ensemble means produce a quarter to third of an inch of QPF
between 00z Thu and 00z Fri and deterministic soundings show cold
profiles with a deep DGZ layer and light sub-DGZ winds. After
coordination with neighboring offices, decided that raising SLRs
for this initial wave of WAA precip was justified before winds
increase as the main system develops and moves closer. While
impacts with this snowfall appear to be low, this fluffy snowfall
could exacerbate blowing/drifting concerns Thursday night into
Friday when winds increase. With regards to the main system, the
most recent 12/00z model suites moved substantially in the
direction of a consensus solution increasing forecaster confidence
of high-impact winter weather to medium/high levels. By 12z
Friday, operational GFS, ECMWF, and CMC all have a ~980mb low
between Chicago and Detroit with the GFS now the farther west
solution while the ECMWF remains most consistent. Most individual
ensemble member solutions of all three major models are west of
the ensemble mean suggesting a substantial shift back to the east
is very unlikely. The general ensemble consensus suggests at
~980mb low near Grand Rapids, MI or southern Lake MI at 12z
Friday. Further deepening to a sub-970mb low seems likely as it
lifts northeast to near James Bay by 12z Saturday. This storm
track is further supported by a baroclinic zone between Lake MI`s
warm water and deep and dense snow pack laid down west of Lake MI.

Details regarding extent, timing, and magnitude of winter weather
hazards are a long way from being sorted out, but the latest EFI
and SoT guidance (00z 12/18) continues to support the idea of
highly unusual if not historic combination of wind and snow. The
worst combination of snow and wind appears to be focused within
the 00z Fri-00z Sat time frame when most model guidance indicates
blizzard conditions across the area. By Saturday morning, 2m temps
should be in single digits across the west and around 20 across
the east with wind chills roughly 10-20F cooler. This west-east
temperature gradient could be present throughout the storm
resulting in substantially different impacts across the west
(drier snow, more blowing/drifting) than the east (wetter snow
especially early, potential for power outages). The harsh winter
conditions should become more localized as the low pulls away from
our area. Even as this occurs, ensemble mean 850mb temps around
-20C at 00z Sun and GLERL analyzed lake-average SSTs of 4C
 indicates LES will still be going in northwest wind snow belts.
 In fact, it`s possible that LES continues until the next system
 arrives early next week.

[Madtown]

What's it look like Money

[Money]

6 minutes ago, Madtown said:

What's it look like Money

Not sure just read that it was east by about 50 miles and was less amped 

[Ottawa CO, MI]

Looks like another miss for West Michigan in terms of missing the heavy snowfall...

[westMJim]

11 minutes ago, Ottawa CO, MI said:

Looks like another miss for West Michigan in terms of missing the heavy snowfall.

Here in West Michigan we get mostly lake effect with a much less chance of system snows. Even the east side of the state gets heavy system snow more than we do. Just a matter of location.

[gosaints]

Goalposts still huge this morning.  Even a turd is still on the table. 

[Money]

HR 90 euro 

[gosaints]

Goalposts still huge this morning.  Even a turd is still on the table.

[Money]

2 minutes ago, gosaints said:

Goalposts still huge this morning.  Even a turd is still on the table.

You’re definitely still in the game for sure 

[jaster220]

In case this wasn't posted already. GRR

Then, starting Thursday night, things get really interesting. In
both the 18/12Z and 19/00Z runs of the ECE, a sizable majority of
members show explosive cyclogenesis of a surface low originating
from the mid-MS valley region and moving northeast into Lower MI or
possibly eastern WI. Forecast deepening of the surface low Thursday
night is unbelievable. The entire ensemble mean drops about 8 mb
between 00Z and 06Z Friday and both the ECMWF and Canadian
deterministic runs show a drop of 20 mb between 00Z and 12Z as the
low center pulls into Lower MI.

We continue to see evidence of a large TROWAL accompanying this
explosive cyclogenesis. Copious snowfall associated with the TROWAL
would likely be juxtaposed with very strong winds and apparent
temperatures dropping into the single digits by early Friday
afternoon. If this scenario were to pan out, we would be well into
blizzard territory by Friday afternoon. This would be followed by a
prolonged period of significant lake enhanced snow lasting most, if
not all, of Christmas weekend.

Obviously, a lot still can change between now and the end of the
week. But, we have observed that the entire model suite has been
extraordinarily consistent with this system, strongly suggesting
greater than average predictability at this time range. The WPC
cluster analyses seem more locked into a solution too. To
illustrate, the 18/12Z WPC analysis showed cluster 1 alone
explaining about 43 percent of the total ensemble spread and its
membership is almost entirely ECMWF and Canadian ensemble members.
This is not surprising given how much in lockstep these ensembles
have been with this system in general.

So, there is increased cause for concern, certainly more than there
was at this time yesterday. Probabilities for a very impactful
system at the end of the week into the holiday weekend are now
uncomfortably high. Accordingly, now is the time to start thinking
about preparing for this possible scenario.

[winterfreak]

6z EURO is definitely dryer down here. 

[CentralNebWeather]

NWS Hastings has issued a Winter Storm Watch and Wind Chill Watch.  They mention blizzard several times in their disco.  Have initially set snowfall amounts at 2-4", which is odd in that NWS North Platte has 4-6" in their watch and looks like my area would be in heavier snow longer.  They ripped the GFS and basically said throw it out.  They did say there is still time for adjustments to snow, but don't see it adjusted upwards. 

In all the years I've been following them, I don't remember them ever going with the over on snow.  They've been wrong many times on amounts and I've called them out.  They may be totally right, but I don't know why they always downplay snow.  Oh well, let's see how it plays out.  They are very concerned about the combination of blowing snow and wind chill values as low as -45.  I would almost bet that a blizzard warning is issued sometime on Wednesday.  

[gosaints]

The EURO solution tells my gut that the GFS has over corrected.

[gosaints]

Reading the tea leaves from americanwx and the WPC lots of mets riding an eastern solution to the main event.

[Madtown]

John dee for the win 

 

https://johndee.com/forecast-graphic/

[tStacsh]

55 minutes ago, jaster220 said:

In case this wasn't posted already. GRR

Then, starting Thursday night, things get really interesting. In
both the 18/12Z and 19/00Z runs of the ECE, a sizable majority of
members show explosive cyclogenesis of a surface low originating
from the mid-MS valley region and moving northeast into Lower MI or
possibly eastern WI. Forecast deepening of the surface low Thursday
night is unbelievable. The entire ensemble mean drops about 8 mb
between 00Z and 06Z Friday and both the ECMWF and Canadian
deterministic runs show a drop of 20 mb between 00Z and 12Z as the
low center pulls into Lower MI.

We continue to see evidence of a large TROWAL accompanying this
explosive cyclogenesis. Copious snowfall associated with the TROWAL
would likely be juxtaposed with very strong winds and apparent
temperatures dropping into the single digits by early Friday
afternoon. If this scenario were to pan out, we would be well into
blizzard territory by Friday afternoon. This would be followed by a
prolonged period of significant lake enhanced snow lasting most, if
not all, of Christmas weekend.

Obviously, a lot still can change between now and the end of the
week. But, we have observed that the entire model suite has been
extraordinarily consistent with this system, strongly suggesting
greater than average predictability at this time range. The WPC
cluster analyses seem more locked into a solution too. To
illustrate, the 18/12Z WPC analysis showed cluster 1 alone
explaining about 43 percent of the total ensemble spread and its
membership is almost entirely ECMWF and Canadian ensemble members.
This is not surprising given how much in lockstep these ensembles
have been with this system in general.

So, there is increased cause for concern, certainly more than there
was at this time yesterday. Probabilities for a very impactful
system at the end of the week into the holiday weekend are now
uncomfortably high. Accordingly, now is the time to start thinking
about preparing for this possible scenario.

Meh, this is going west of here.  disappointing.  But the more I think about it, the less i want a crippling blizzard this weekend.  

 

I'm sure the backside will be filthy though.  

[Clinton]

1 hour ago, sumweatherdude said:

GFS further north on the 06z run.  If it continues, KC will be too far south. 

I hope it doesn't.   With the AO and NAO so deeply negative I can't imagine it would go further north than cycle 1.

[Tony]

Man, the GFS has been all over the place with this storm. From the East Coast and now the farthest west solution. Euro, and dare I say ICON has been steadfast with their solutions for several runs now and UK not too far off. Not saying the GFS is wrong but what whacky model. By tomorrow hopefully we will have some type of solution as to the track, but the evolution seems to be set.

[Tony]

I'm really looking forward to the upcoming NAM runs as the numbers should be off the chart. Fun modeling times ahead.

 

[tStacsh]

Euro vs GFS.  Who wins?  and Why? Go.

[Jayhawker85]

There is a severe case of modelitis in the board. Lol just because one model run shows a different solution doesn’t mean that that’s “the trend”. We all know models will differ greatly outside of 48 hours before the storm 

[gosaints]

1 minute ago, tStacsh said:

Euro vs GFS.  Who wins?  and Why? Go.

I would vote somewhere closer to the EURO.  My simple reasoning is the GFS outcome interms of strength and deepening is extremely rare.  Statistically the EURO outcome is simply more likely.

[Hawkeye]

I hate seeing the Euro trending east, with a delayed blow-up.  That makes it difficult to buy the GFS.

[winterfreak]

Ugh. 12z NAM is UGLY around here.

[Bellona]

Anything is on the table still I'd say. I can't help but get excited and take things with a grain of salt. Do I ever think I'll get 27 inches of snow here, no. Half of that, hell, 1/3 of that I'd be good with!

[winterfreak]

EURO is the way to go. As it almost always is. NWS offices seem to agree.

[BMT]

imo - just happy its looking like a lock for a white Christmas.  better than the 60 degree brown christmas' as of late.  

[gosaints]

This is way out of the NAM's wheelhouse.  Obviously this far out but also in terms of set up

[bud2380]

Even though the NAM isn't trustworthy at this range, it's showing a solution currently that is my biggest fear for Eastern Iowa.  And in fact the Euro isn't all that far off from what the NAM shows around here, namely the lead band of precip basically stalls out from Lake Superior back to the southwest into central Nebraska.  And as it tries to move east, it stalls and weakens, but dumps several inches of snow in eastern NE, western IA into SD, MN and WI, leaving little if any snow in Eastern Iowa.  Then as the main energy starts to shunt off to the east that band quickly moves through eastern Iowa, leaving only a few inches of snow, with the storm eventually wrapping up to our east, so we only get a very quick progressive bout of snow here.  So we either want that initial band to setup further east or the wrapped up system to come further west.  We may be right in between here and get the screw zone with heavier totals in every direction.  

 

 

[Jayhawker85]

18 minutes ago, winterfreak said:

Ugh. 12z NAM is UGLY around here.

How is it ugly? It develops a heavy band over the city 

[Hawkeye]

Each of the two latest RDPS runs is digging a bit less and shifting east, like the Euro.  

Looking at the Euro, its last two runs have shown the trough way out in the Pacific shifting east, which pushes the west-coast ridge east, which pushes our storm east.

[gosaints]

That energy just parking off the pacific coast isnt going to aid models

[tStacsh]

Ugh,  On one hand I'm exciting to have the possibility of a top 10 event.  On the other hand, I don't want to be snowed in for a day or 2.  

[bud2380]

4 minutes ago, Hawkeye said:

Each of the two latest RDPS runs is digging a bit less and shifting east, like the Euro.  

Looking at the Euro, its last two runs have shown the trough way out in the Pacific shifting east, which pushes the west-coast ridge east, which pushes our storm east.

The 6z Euro actually only shows it snowing in eastern Iowa for about 9 hours.  It will be hard to get more than 3-4" if that is the case.  

[bud2380]

12z RDPS (short range Canadian)

This is a helluva lot better than what the NAM is showing at least.  This is as far as the model goes, so more snow falls than depicted here for anyone east of DSM.  

[Hawkeye]

I'm thinking the last two GFS runs are as good as we'll see for Iowa.  It'll probably start backing off a bit today.

[Bellona]

Dmx says ratios 20:1. What are the opinions? I know it's definitely cold enough for ratios that high but with the winds, I don't know how realized that will be.

[Hawkeye]

The 12z ICON is pretty steady, hits northern IL into Wisconsin the hardest.