December 2020 Observations and Discussion

[Tom 15614]

Folks, we have just about made it through 2020, but first, we need to get through the last month of the calendar year and the start of met Winter!  Who's ready??  If there is anyone on here that is more eager to see a fast start to winter...raise your hands up in the air!  Finally, after many false starts in years past, most of our Sub across the eastern/southern tier will indeed be "flipping the script" this year in 2020.  After analyzing a ton of data and using LR  pattern recognition techniques, it does appear highly likely that the long awaited start to met Winter will feature an exciting start if you live in the eastern Sub.  On the flip side, those of you up north and even out west, you'll prob have to wait till mid month for some action.

Where shall we begin???  Let's start at the top of the atmosphere at 10mb and focus on the evolution of the Polar Vortex.  Even though the models are predicting a strong PV, similar to 2013-14, it does favor a NW Flow aloft and some slight influence of warming near Siberia/N PAC that will influence the PV and "funnel" cold air into North America.

 

My gut told me early on that this would be the year of the return of the "Greenland Block".  Wouldn't ya know it, in a timely fashion, it will appear as we open up December.  It took a while, but in recent days, all the modeling is picking up on an expansive block to open up December.  

 

When do I think the action will shift farther west???  Well, the tool that has been rock solid for me this season is the clues up in the Strat and where warm/cold pools are forming.  Take a look at the last frames in the 50mb animation below right around Nov 20-22nd...you see the blue colors (trough) shift from the EC down into the SW.  This is when we will enter a period of SW Flow aloft and I think this is the time when the LRC had some interesting storm systems.  I'll have to look back in more detail in the days ahead.  I'm guessing the Week of the 13th (lucky #) will feature a mid month rally, or rather, a very active period.  Using the BSR as guidance, there are potentially multiple storm systems we will be tracking during this week.

 

 

The target period for when this SW Flow pattern starts is between the 12th-15th and the looks according to the BSR would translate towards a "cutter", may be hard cutter....followed by more storm systems leading up towards the Winter Solstice period that would track farther south.  Could this be a "share the wealth" month for all???  Let's hope mother nature can contribute to all of us in the snow dept and have a fantastic holiday season!  Let's discuss....

 

 

[james1976 3688]

Gonna be cold and dry and prolly windy for my area next week on the backside of that big storm. Yuck. Oh well.....I'm glad someone in here looks to score bigly as we open met Winter.

[FAR_Weather 4920]

Maybe Michigan will actually have a Winter this year!

[james1976 3688]

GFS much further east

[FAR_Weather 4920]

Lol, congrats Kentucky.

[OmahaSnowFan 941]

We'll see what actually happens this month. We've gone from this is going to be a 6 month long winter, to November turning into a nothing burger, to just last week saying everything doesn't show winter until maybe February, to suddenly this week December is going to be amaze-balls and I knew it all along!!

[GDR 639]

I’m surprised the Dakotas aren’t buried yet in snow

[Tom 15614]

12z Euro with an OH bomb...will post maps when fully loaded...huge hit for all of IN and W MI...

[Tony 739]

Euro keeping hopes alive for a major snowstorm...so the model mayhem continues for the next several days. 

[Clinton 3628]

12Z Euro.  

[Tom 15614]

3 minutes ago, Clinton said:

12Z Euro.  

This is insane!  Historic open to December....???  December to Remember....#flipthescript2020

[Tom 15614]

12z Euro...another look...

[Niko 6813]

This storm stalls for days in Oh.....wow!

[Hawkeye 3845]

It becomes a highly-amplified, blocked-up pattern, but for everyone too far west to get anything from the potentially-big eastern storm it's a total snoozer.

[Tom 15614]

3 minutes ago, Niko said:

This storm stalls for days in Oh.....wow!

I love it...just hope the Euro is right and is accurately picking up on the blocking pattern.  Man, what a beauty of a storm....loads of precip and just enough cold air.  Systems this powerful can generate their "own brewed" cold as well. Those finer details can get ironed out later.  I'm liking the trends at this range.  Max wind gust top out around 55 mph along the lake to top it all off.  

[james1976 3688]

When on earth will I ever see a map like that for mby??? Jealous!

[snowstorm83 1260]

brb, moving to Lexington Kentucky

[Niko 6813]

28 minutes ago, Tom said:

I love it...just hope the Euro is right and is accurately picking up on the blocking pattern.  Man, what a beauty of a storm....loads of precip and just enough cold air.  Systems this powerful can generate their "own brewed" cold as well. Those finer details can get ironed out later.  I'm liking the trends at this range.  Max wind gust top out around 55 mph along the lake to top it all off.  

Its a beast!

[Clinton 3628]

This system look familiar to me.  I expect this to trend colder aswell.

[james1976 3688]

10 minutes ago, Clinton said:

This system look familiar to me.  I expect this to trend colder aswell.

Do the ensembles go out further than the op runs?

[Clinton 3628]

2 minutes ago, james1976 said:

Do the ensembles go out further than the op runs?

Yes they go out to 360hrs.

[Niko 6813]

Accu-Weather feels confident that this track plays......

[Stacsh 783]

So far out.  Euro has been bad lately, hopefully it gets some support soon.  

[CentralNebWeather 3772]

1 hour ago, james1976 said:

When on earth will I ever see a map like that for mby??? Jealous!

100% agree. Not a flake or drop predicted for the foreseeable future around here. 

[Stacsh 783]

It's funny how one run can get you pumped up, but then realize this isn't your storm in W. Michigan.  Going to be APP/ East coast storm.  Congrats Pennsylvania and the Upper NE.  

[jaster220 8046]

1 hour ago, Stacsh said:

It's funny how one run can get you pumped up, but then realize this isn't your storm in W. Michigan.  Going to be APP/ East coast storm.  Congrats Pennsylvania and the Upper NE.  

Needs to get it's butt further north for sure!

[jaster220 8046]

3 hours ago, Tom said:

I love it...just hope the Euro is right and is accurately picking up on the blocking pattern.  Man, what a beauty of a storm....loads of precip and just enough cold air.  Systems this powerful can generate their "own brewed" cold as well. Those finer details can get ironed out later.  I'm liking the trends at this range.  Max wind gust top out around 55 mph along the lake to top it all off.  

After the UK lost the phased look, was sure the Euro Would follow. I've seen the EC go huge 3 consecutive runs just to fold it's hand and admit to bluffing. I think it has gone 4 in a row now so I'm in uncharted territory tbh. It will be interesting to see if it can lead the way and shine-up it's tarnished crown. Ofc I'm cheering for that (and a little bump north). 

[jaster220 8046]

1 hour ago, Stacsh said:

It's funny how one run can get you pumped up, but then realize this isn't your storm in W. Michigan.  Going to be APP/ East coast storm.  Congrats Pennsylvania and the Upper NE.  

 

2 hours ago, Stacsh said:

So far out.  Euro has been bad lately, hopefully it gets some support soon.  

Need the Euro strength but the GEM's track = KISMET

 

[Niko 6813]

Not sure, but I think the GEFS inundates the "Lakes" w tremendous amount of snowfall.

[james1976 3688]

GFS OP just looks like a mess. Not saying it can't happen but its super unorganized. 

[jaster220 8046]

GRR gives a very good write-up treatment of the situation as of earlier today. Much more impressive breakdown than typically seen.

-- Possible wintry weather early next week --

Projecting the location and intensity of phased systems is a vexing
issue, and next week is no exception. A trough is currently moving
into the Pacific Northwest region and models are coming into
agreement that the southern portion of the trough will detach and
become an upper low cutoff over the Four Corners region. This upper
low is forecast to migrate east over the Rockies before attempting
to phase with a secondary, digging trough over the Midwest and Great
Lakes region. Where this phasing occurs will determine if we get
significant snowfall or not.

Not surprisingly, current long range guidance continues to feature
spread with where the upper level phasing induces low level
cyclogenesis. A probabilistic approach based on ensemble data
indicates more members are favoring cyclogenesis across the lower
Ohio Valley or Appalachians Monday into Tuesday, as opposed to the
Great Lakes. However, depending on how intense the upper level
phasing is, a negatively tilted upper low could substantially pivot
and deepen the surface low toward the north/northwest, potentially
impacting Lower Michigan. That scenario is supported by some ECE
members though most others prefer an Appalachian/East Coast track.
The GEFS and CMC members favor the Appalachian track as well.

Let`s suppose the scenario occurs where a deep/intense phasing of
the systems near the Great Lakes induces a deep surface low across
northern OH / southeast MI. Current and past runs of the ECMWF/GEM
would support double digit snow totals (spread out over a couple
days) across much of the region, which would make this the first
significant winter storm to impact Michigan this season. However,
assuming the phasing occurs across the Appalachians (ECE, GFS,
GEFS, CMC), we see only minor snowfall, or perhaps none at all.
Current odds are tilted in this direction but it is obviously
something we are watching closely given the higher impacts that
could potentially occur.

[whatitdo 105]

28 minutes ago, jaster220 said:

GRR gives a very good write-up treatment of the situation as of earlier today. Much more impressive breakdown than typically seen.

-- Possible wintry weather early next week --

Projecting the location and intensity of phased systems is a vexing
issue, and next week is no exception. A trough is currently moving
into the Pacific Northwest region and models are coming into
agreement that the southern portion of the trough will detach and
become an upper low cutoff over the Four Corners region. This upper
low is forecast to migrate east over the Rockies before attempting
to phase with a secondary, digging trough over the Midwest and Great
Lakes region. Where this phasing occurs will determine if we get
significant snowfall or not.

Not surprisingly, current long range guidance continues to feature
spread with where the upper level phasing induces low level
cyclogenesis. A probabilistic approach based on ensemble data
indicates more members are favoring cyclogenesis across the lower
Ohio Valley or Appalachians Monday into Tuesday, as opposed to the
Great Lakes. However, depending on how intense the upper level
phasing is, a negatively tilted upper low could substantially pivot
and deepen the surface low toward the north/northwest, potentially
impacting Lower Michigan. That scenario is supported by some ECE
members though most others prefer an Appalachian/East Coast track.
The GEFS and CMC members favor the Appalachian track as well.

Let`s suppose the scenario occurs where a deep/intense phasing of
the systems near the Great Lakes induces a deep surface low across
northern OH / southeast MI. Current and past runs of the ECMWF/GEM
would support double digit snow totals (spread out over a couple
days) across much of the region, which would make this the first
significant winter storm to impact Michigan this season. However,
assuming the phasing occurs across the Appalachians (ECE, GFS,
GEFS, CMC), we see only minor snowfall, or perhaps none at all.
Current odds are tilted in this direction but it is obviously
something we are watching closely given the higher impacts that
could potentially occur.

Looks like they think it’s less likely to hit the midwest despite euro’s consistency in the track to do just that. What you thinking? 

[Clinton 3628]

18z EC with snow still falling over Mich at the end of the run.  It's a little weaker than it has been but the track is still good for you guys.

[jaster220 8046]

2 hours ago, Clinton said:

18z EC with snow still falling over Mich at the end of the run.  It's a little weaker than it has been but the track is still good for you guys.

Thx, btw, what's the "Ens [C]" exactly? And yeah, that's a lot weaker actually, but glad to see it not just vanish.

[Clinton 3628]

2 minutes ago, jaster220 said:

Thx, btw, what's the "Ens [C]" exactly? And yeah, that's a lot weaker actually, but glad to see it not just vanish.

The Euro Control.  The CMC held serve aswell.

[jaster220 8046]

7 minutes ago, Clinton said:

The Euro Control.  The CMC held serve aswell.

Nice! (CMC and GEM are one and the same, no? confused by GRR's AFD saying the GEM was for the Lakes, but the CMC was more east)

[Clinton 3628]

1 minute ago, jaster220 said:

Nice! (CMC and GEM are one and the same, no? confused by GRR's AFD saying the GEM was for the Lakes, but the CMC was more east)

I always thought so, that is confusing.

[jaster220 8046]

1 minute ago, Clinton said:

I always thought so, that is confusing.

Here it is..

Quote

Current and past runs of the ECMWF/GEM
would support double digit snow totals (spread out over a couple
days) across much of the region, which would make this the first
significant winter storm to impact Michigan this season. However,
assuming the phasing occurs across the Appalachians (ECE, GFS,
GEFS, CMC), we see only minor snowfall, or perhaps none at all.

 

[jaster220 8046]

0z GEM comes up east of the Mitt and keeps moving instead of curling back and spinning around for 2 extra days. It even clips my county with a second storm 48 hrs after the first one has moved out of the lakes.

[jaster220 8046]

3 hours ago, whatitdo said:

Looks like they think it’s less likely to hit the midwest despite euro’s consistency in the track to do just that. What you thinking? 

It's tough to say at this point if the Euro is legit. Phase-bombs are a serious rarity around the OHV/Lakes region so that would argue against it. Over the years a model or two will flash a run showing such in the fantasy long range, but then immediately drop it. Iirc, there was a better looking chance leading up to Christmas of 2014 but the cold air failed to get pulled south out of Canada so it ended up a dud. Dec 2014 was a warm month similar to what we've got going on right now fwiw. I referenced the Nov 1950 storm which gave this area about 7" but that was during an extremely cold autumn regime. There is Nov 2-3. 1966 which phased and delivered the goods (12" KBTL) and the only other time I've seen a mild regime go bomb cyclone for Michigan was 11/16/89 and that one had zero degree airmass just north of Superior to work with. Maps in order of events.

 

[jaster220 8046]

5 hours ago, Niko said:

Not sure, but I think the GEFS inundates the "Lakes" w tremendous amount of snowfall.

That'd be great, but I'm not seeing that from the GEFS. Where did you see that bud?

[jaster220 8046]

As a footnote to my historic early season bomb storm post above, I have to add this comment. Traditionally, when the models showed a storm from about 120 hrs out, there was a good chance it would happen and be worthy of starting a thread. Tonight's 0z GEM run has snow breaking out already at h96 so we're easily inside the range when models would've lost the storm completely if it were a "false flag". The only caveat ofc is we are talking about a potential phase-bomb which are the trickiest of tricky scenarios for the models to handle.

Tonight's GEM run actually has 3 snow-makers in the next 10 days. This map includes just the first potential phaser:

 

[jaster220 8046]

0z Euro goes towards the GEM with both track/intensity & less sit-n-spin. Ofc everything is less stunning, including total snowfall but perhaps more realistic tbh.

 

[jaster220 8046]

I like this from APX

Quote

The forecast starts out relatively easy then becomes increasingly
complex. First the easy part, zonal flow aloft Saturday night into
Sunday yields precipitation free and mild conditions. A surface cold
front then moves across northern Michigan Sunday afternoon and
evening, perhaps igniting a rain or snow shower. All bets are off
after that. The complex part hinges around whether the northern jet
is able to merge with the southern jet early next week. I mean it
likely will eventually but exactly how far to our east this occurs
will determine impacts (if any). Models continue to advertise a
deepening area of low pressure developing to our south and fairly
far to our east but some models retrograde this system to the west
all the way into the western Great Lakes as it becomes captured by
an upper low associated with the northern jet stream. Looking at the
50 ensemble members from the 25/00z ECMWF, close to half retrograde
the low and bring several inches of snow (along with blowing snow)
to northern Michigan while the other half keep it well east with
little to no impact on the area. It`s a tough call honestly on what
the outcome will be and while retrogression is possible it is a
fairly rare occurrence. The farther east solution seems to be more
realistic imo (in my opinion) at this point. Time will tell on how
this system unfolds which will be important since there are
currently stark differences in the possible amount of wind and
precipitation. Keep appraised of later forecasts for any changes in
thinking. Will keep pops in the chance category for now and hope we
can pin down the details as we get closer. Mild temperatures once
again Sunday will be followed by forecast readings closer to normal
during the first half of next week.

 

[jaster220 8046]

0z GFS has decided maybe it wants back in the party after all. 980's SLP seems to be in vogue now vs. the crazy 970's being flashed before.

 

[Tom 15614]

It is looking more and more likely that there will be an impactful system to track..time for a storm thread today after 12z runs???  With that being said, the 00z Euro continues to show a powerful storm but the 00z Ukie now the only model not showing anything when it was the one which was most consistent a day or two ago.  Chitown riding the edge with this one as well as WI peeps.

 

 

 

00z EPS holding steadfast and pointing towards an OHV major winter storm in the making...I think this storm may make up all the dud years this region has recently seen.  Ya'll ready???

[Tom 15614]

While sitting here and sippin' on my coffee, flipping through multiple windows open on my comp and analyzing a ton of data...I'm encouraged to see continued support that an interesting month lies ahead for the start of met Winter (esp the eastern/southern Sub).  For weeks and months, the majority of the climate models were advertising a blow torch December for most of our Sub.  The caveat??  They all seemed to miss the blocking signal near Greenland and now what is looking like a western NAMER ridge that will grow heading into Week 2 of the month.  The latest JMA weeklies came in this morning and do favor the eastern CONUS trough for most of the 1st half of December, but then I see a more traditional signal for a La Nina pattern setting up with the N stream coming back into play for the second half of the month.  Depending on the exact length of the LRC, I will say, I'm expecting to see more of a SW Flow develop by the middle and end of the month.  Those of you out farther west and north will then begin to share in the wealth and see more chances of storminess.

Week 2...

Temp...

 

Week 3-4...that Greenland Block is gonna rock this month...

 

Temp/Precip patter...I think the model is too warm in the Plains/Upper MW...should trend colder and wetter...the wet signal near the GL's/N Rockies/Upper MW should expand South IMO...

 

 

 

 Notice the upward motion across the Indian Ocean and the sinking air across the central PAC.  These are favorable colder MJO phases for Week 3-4 and that would lead us up towards the Winter Solstice/Christmas Holiday.  Things are really looking promising!

 

 

[Clinton 3628]

@OKwx2k4 Oz Euro has a gift for ya.  The EC went bonkers with this and produced a 12 inch storm in your back yard.

[Tom 15614]

Long ways ahead, but there may be a signal growing that a SSW event could be brewing right around the Week of the 13th or just prior across Siberia.  This can lead to perturbing the PV in a similar fashion as it did back in '13-'14, supporting a more "reflective" look which can seed some real cold arctic air into North America.  Interestingly, the models are starting to see a much colder look by the 2nd week of Dec.  00z GEFS 10mb strat forecast and 500mb pattern is telling me to watch for colder trends.

 

 

00z GEFS 500mb...way back in Sept/Oct, the pattern near Scandinavia was catching my eye and would be a crucial part of this Winter's pattern.  It is indeed playing a big role for North America.

 

[Tom 15614]

2 minutes ago, Clinton said:

@OKwx2k4 Oz Euro has a gift for ya.  The EC went bonkers with this and produced a 12 inch storm in your back yard.

He may have several chances for winter storms this month from all indications.  The blocking is really going to justify if the southern stream converge with the N stream later this month.