December 21st-24th, 2022 | Plains/MW/GL/OV Winter Storm

[snowlover2]

[ak9971]

Snow coverage is pretty weak though, almost zero wrap around snow which is pretty realistic. Positive trend though that euro remains steady, I’d expect GFS to correct back tomorrow. 
 

[CrazyINwx]

Here's the Kuchera

[Ingyball]

All ensembles trend up for me. We'll see how long this west trend continues and if I'll be asking for it to shift back east in a day 🤣

[Central Illinois]

WPC

[Ohiobuckeye45]

[Ohiobuckeye45]

[CrazyINwx]

They're similar. 😄 

[Ohiobuckeye45]

[Ohiobuckeye45]

[Ohiobuckeye45]

[StLweatherjunkie]

4 hours ago, StormfanaticInd said:

If this storm really does cut west then this December will be an all time epic bust by Bastardi. Yikes! Lol

It won't be the first or last time Bastardi busts big time ... 

[StLweatherjunkie]

41 minutes ago, Ohiobuckeye45 said:

A low centered over the Mackinac straits is almost perfect for MBY ... Fingers are crossed for that .😍

[TheBlizzardOf1978]

Quote

000
FXUS63 KIND 190803
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
303 AM EST Mon Dec 19 2022

Long Term...(Wednesday Night through Sunday)
Issued at 303 AM EST Mon Dec 19 2022

Thursday through Saturday(Potential Winter System)...

Confidence remains high in the potential for an impactful low
pressure system to pass through the Great Lakes region sometime
between Thursday morning and Friday. With that said, there is still
significant variability on the overall track and progression of the
low leading to uncertainty with timing and potential snow
accumulations

*************************
Synoptic Pattern and Conceptual Model:
*************************

The overall synoptic pattern is fairly typical of an impactful
Midwestern winter storm. A very strong northwesterly upper level jet,
upstream of a trough will create strong negative height tendency
over the Intermountain West and Great Plains. The trough will slowly
become negatively tilted as the maximum vorticity advection pushes
downstream of the trough. Meanwhile, intense CAA will simultaneously
support upper level trough development.

Near the surface, the aforementioned CAA, and weaker WAA over the
Mississippi Valley will lead to an increasing pressure gradient.
This coupled with upper level diffluence will allow surface
cyclogenesis. Current thoughts are for cyclogenesis to occur over
the Arklatex region, with a NE progression following the CVA and
diffluence maximum. Later in its life cycle, the polar jet will wrap
around the trough, creating peak levels of diffluence. This in
combination with a strong baroclinicity will create an efficient
environment for surface pressure depletion with a MSLP at 980mb or
lower over the Great Lakes region late this week. What makes this
set-up quite anomalous is the significant temperature gradient
between the cold and warm sector, aiding in the dynamic progression
of the low.

This general idea has become more consistent amongst both
deterministic and ensemble member solutions. There is still plenty
of variability on low track, of which should improve as the cold air
mass and parent trough are better sampled through observations.

**********************************
Ensemble and Probabilistic Output:
**********************************

With much better consistency between ensemble members, utilizing
means and probabilistic output can identify significant trends in
solutions. This can help increase confidence in expected outcomes.
There are still plenty of varying outcomes, and trends can flip,
which is why even single run consistency still does not always
indicate high confidence.

The latest ensemble suite (00Z) from both the GFS and ECMWF are
pointing towards a low track NW of Indianapolis, leading to warmer
temperatures and rain initially on Thursday. Of note though is the
lack of true occlusion and bomb cyclogenesis in most members until
after passing through central IL. This could lead to solutions of a
low track further to the east as the cold air is better sampled.
Still, even with this uncertainty, a track NW of Indianapolis looks
more likely.

Confidence continues to remain high on both extremely cold
temperatures and high winds in the wake of the low both Friday and
Saturday. Nearly all ensemble members have at least 20MPH sustained
winds on Friday, with most having gusts of at least 40MPH at times.
The extent of cold air will be influenced by any potential snow
pack, but lows at least in the low single digits look likely for
Saturday morning. The combination of wind and cold will lead to
dangerous wind chills, the coldest being Friday night near or below -
20.

As the system occludes, moisture will wrap around the low leading to
snow chances. This can be seen by an increase of snow probabilities
Friday and Friday night. Any snow that does fall will likely have
significant drifting leading to even further travel difficulties.
Snow fall totals range significantly as ensemble members struggle to
understand the low progression and evolution. The range of outcomes
for snowfall still range from marginal to highly impactful. There
also is the potential for a flash freeze as rainfall on Thursday
quickly freezes within the arctic airmass.

********************************************
Winter Storm and Arctic Outbreak Conclusion:
********************************************

A deep low pressure system is expected to progress through the Great
Lakes region Thursday through Saturday. This will provide widespread
precipitation over central Indiana Thursday afternoon through Friday
Night. Initially, p-type is uncertain, but by Friday central Indiana
will be well below freezing with any precipitation falling as snow.

Despite uncertainties regarding the potential winter storm Thursday
into Friday, there are a few areas where forecast confidence is very
high. No matter the track of the upcoming storm system, confidence
remains very high that some of the coldest air of the year will
arrive by the holiday weekend with temperatures potentially falling
below zero! Any snowpack will further allow temperatures to plummet
into the negatives and possibly into record territory. Along with
the cold air will likely be dangerously cold wind chill with values
possibly below -20F. High winds and/or snow could also lead to power
outages further enhancing the potential risks. Take precautions now
to prepare for the upcoming cold weather this holiday weekend.

Areas of higher confidence:
* Period of high winds with a wind shift to the NW Thurs into Fri
* Extremely cold arctic air this weekend with temperatures falling
  near or below zero
* Dangerous wind chills possibly down to -20F to -30F this weekend
* Periods of snow showers on the backside of the system Fri into Sat

Areas of lower confidence:
* Exact storm track and where areas of heavy snowfall could set up
* Snowfall amounts remain very uncertain at the moment, higher
  confidence in accumulating snow further north and west
* Temperatures Thursday into Friday, could vary significantly across
  short distances through the state depending on track of the system

 

Edited December 19, 2022 by Hiramite

[CrazyINwx]

[Ingyball]

If I weren't so confident in these models underestimating the movement of the cold air I'd be worried about these north shifts but at least now it looks like this won't shift so far south that I get screwed on the northern side.

 

 

 

Edited December 19, 2022 by Ingyball

[StormfanaticInd]

The models need to figure this out ASAP because of the serious nature of this storm. A last minute shift back east would catch a lot of people off guard 

[StormfanaticInd]

This flash freeze could happen right during the middle of the morning rush hour Friday 

[RadioWX]

Bernie says he feels GFS is too far west.   Thinks a St Louis - Detroit track is where this ends up 

 

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[StLweatherjunkie]

19 minutes ago, StormfanaticInd said:

The models need to figure this out ASAP because of the serious nature of this storm. A last minute shift back east would catch a lot of people off guard 

IMHO, it kind of feels like the models did figure it out ... the Euro was right two days ago 😄

[StormfanaticInd]

Man...😱

 

[StormfanaticInd]

8 minutes ago, StLweatherjunkie said:

IMHO, it kind of feels like the models did figure it out ... the Euro was right two days ago 😄

Oz gfs is too amped imo. The euro has been far more consistent

[Jpfalcon]

Local mets on board with the western track. Wind and cold will be a bigger story here than precip. Those set up to get blasted, enjoy! 

[StLweatherjunkie]

1 minute ago, StormfanaticInd said:

Oz gfs is too amped imo. The euro has been far more consistent

The goofus has been all over the place proving it's unreliable and should be tossed. Why not just pay attention to the Euro?

[StormfanaticInd]

2 minutes ago, StLweatherjunkie said:

The goofus has been all over the place proving it's unreliable and should be tossed. Why not just pay attention to the Euro?

I pay attention to what makes sense.