11/24 - 11/26 Winter Storm

[brianc400]

Well if this pans out it will be an interesting welcome for my new colleague from Mexico on his first trip to Chicago.

 

Someone earlier mentioned that the warm lake may keep snow totals down in the city. Yes, but the cold November has driven lake water temps down near 5° below normal for this time of year.

[Grizzcoat]

Yeah - I know HRRR / RAP at long range... but it sure looks a lot like the GFS / FV3

[dubuque473]

I am afraid to get my snowblower ready so as not to jinx any chance at more snow!

[Stormhunter87]

Yeah - I know HRRR / RAP at long range... but it sure looks a lot like the GFS / FV3hrrr_asnow_ncus_31.png

Crazy sharp cut off between Douglas and Sarpy county. Omaha looks like 5 and I'm in the 8 inch area. Either way it did come north a hair

[Stacsh]

Timing?  Niece is driving to central Illinois from West Michigan on Sunday.    Anyone have a time when precip is supposed to break out?

[Grizzcoat]

NAM looks S -- keep me posted -- gotta drive!!!

[Stormhunter87]

NAM is south does something odd over Omaha with snow totals. I would guess the warm air hangs on to long.

[GDR]

Looks like it’s siding with the euro

[GDR]

Chicago gets smoked on the nam

[GDR]

You have to believe the gfs will correct to the euro with the 12z

[Hawkeye]

NAM jumping back south

[GDR]

The Chicago magnet is on full force!! Better start a Indian snow dance to counter the Chicago magnet!

[jaster220]

Chicago gets smoked on the nam

 

Did I not mention NAM would eventually be hotness over our way once in range? 'grats ova there NIL peeps

[jaster220]

@Tom

 

Euro maps you posted sure are some genuine jaw-dropping eye candy, especially by November stds. While it crushes NIL with snow totals, it seems to back off a bit over SMI. Where as the Ukie actually has higher qpf over SWMI. What's your take on why the Euro doesn't just keep the same snow totals eastward into SWMI?

[jaster220]

The Chicago magnet is on full force!! Better start a Indian snow dance to counter the Chicago magnet!

 

Need the Detroit peeps to pump their magnet a touch and pull some of that juicy stuff over mby as well

[GDR]

[snowman1]

Alright, NAM has done its job. Your turn GFS and FV3!

[hlcater]

NAM has not been the least bit consistent. It wavers N/S every other run. While I still think the GFS caves, using the NAM as an indicator probably isn’t wise.

[jaster220]

12z NAM delivers 8" hit here in Calhoun Cnty but that's a 10:1 map. I'm thinking this will be more like 8:1 cement stuff so prolly more like 6"

[GDR]

Icon seems to be a little south

[jaster220]

Nice in-depth disco out of DTX this morning explains some key players on the field and why the 12z suite should be telling for those of us further eastward in the sub.

 

PREV DISCUSSION...
Issued at 324 AM EST Sat Nov 24 2018

DISCUSSION...

Periods of rain will continue this morning and then gradually end
from southwest to northeast across the area as mid level trough axis
pivots through the region. With temperatures in the lower 40s across
the area early this morning, and forecast to edge up into the mid
40s, there is no threat of freezing precipitation with this system.
While rain will end later today, cloudy skies will persist on into
tonight and Sunday.

The next storm system, which has the potential to be much more
impactful, will already be working into the region by late Sunday.
The strong shortwave that will be the main driver of this next
winter storm is currently digging aggressively from the Pacific
Northwest towards the central Rocky Mountains early this morning.
Over the course of the day, this shortwave will phase with an active
subtropical jet with the resultant strong cyclogenesis occurring as
energy emerges into the central high plains.

This system will then take aim on the central Great Lakes and far
northern Ohio Valley. The initial period of cyclogenesis over the
high plains will wane briefly by early Sunday morning, but secondary
develop will ensue as upper jet energy wraps into the system. This
will lead to steady strengthening of low pressure as it tracks from
Missouri into Southern Lower Michigan on Sunday night. The expected
track of this system will be over the top the forecast area which
will put the region in a tight transition zone between heavy snow
along the northern edge of precipitation to rain (eventually
changing to snow) further south. The heaviest precipitation will
focus from 21z-00z through 09z-12z as a well organized deformation
zone lifts across the area.

Snow amount forecasting remains very tricky with this system given
the tight gradient between areas that will see mainly snow and those
that see mainly rain during the heaviest precipitation. At this
time, it appears the Saginaw Valley stands the best chance of
notable snow accumulations with a much lesser chance south to near
the Michigan and Ohio state line. For the forecast, no headlines
will be issue given the remaining uncertainty.

The shortwave in question will be well sampled from the 12z
radiosonde suite. In addition, a secondary PV anomaly digging
through northern British Columbia will be sampled fairly well. As
the strength and speed of this secondary system will impact the
track of the main storm system, this better sampling should allow
the 12z model suite to start honing in on the track of this system.
With this additional information, Winter Storm Watch decisions will
come today this far east into lower Michigan.

While the bulk of precipitation will fall before 12z Monday morning,
lighter precipitation on the tail end of this storm system will
persist into Monday morning. This will either be all snow or
changing quickly to all snow as colder air filters into the area
with the passage of the low pressure center to the east.

A colder weather pattern then sets back up as mean upper trough in
the northern stream expands over the eastern CONUS. This colder
pattern pretty much holds for the balance of next week as 30s will
be common for high temperatures and 20s will be the rule overnight.
Once this strong storm system passes early in the week, only expect
periods of flurries/light snow showers at times as various shortwave
disturbances, enhanced by lake effect activity within cold west to
northwest flow, sweep through the area.

[jaster220]

Icon seems to be a little south

 

Seems like a "nudge" south is going to be a theme for 12z

[Tom]

@Tom

 

Euro maps you posted sure are some genuine jaw-dropping eye candy, especially by November stds. While it crushes NIL with snow totals, it seems to back off a bit over SMI. Where as the Ukie actually has higher qpf over SWMI. What's your take on why the Euro doesn't just keep the same snow totals eastward into SWMI?

It may be seeing a warm layer and thus limiting snow production  At this point, I would pay attn where this pivot happens and where the warm tongue approaches near your area.  It seems to me the higher rez models are bringing it very close to your back yard.  With that in mind, where this rain/snow line sets up, I'm seeing pretty good signals that thunderstorms may get entrenched into the cold sector...Thundersnow???  Man, look at this HRRR and higher rez NAM almost creating a trowel feature towards the end of the run.  Models are suggesting intensification as it approaches the lower GL's.  The trough looks like it may be trying to go neg tilt as it heads up our way...remember, this is where the LRC's long term long wave trough has set up and where systems have intensified so I think this last minute trend is our friend.

 

 

 

 

 

[bud2380]

Well the NAM sucked for my area. It’s even worse than the Euro now. Euro still had 6” over me.

[hlcater]

Why. Are. People. Using. The. NAM?

[Tom]

Timing?  Niece is driving to central Illinois from West Michigan on Sunday.    Anyone have a time when precip is supposed to break out?

Right around Noon or so, if she wants to beat this storm, I think she'll have to leave late tonight around 3:00am or even earlier.

[Tom]

Why. Are. People. Using. The. NAM?

It's not just the NAM, nearly every model is now seeing what the Euro/Ukie have been showing over the past couple runs.

[GDR]

[Tom]

Geeze, this is going to be some low ratio snow around these parts.  Here is WGN's take on the snow amounts right now....

 

[GDR]

12z icon looks like the euro

[MudCutter]

I live about a half hour SE of Dsm. The weather channel says i could get 8-12 inches. What do you guys think?

#bruce 

[GDR]

I wouldn’t go with it more like 1-3

[GDR]

I live about a half hour SE of Dsm. The weather channel says i could get 8-12 inches. What do you guys think?

#bruce

sounds like the gfs but that will head south in the 12z

[bud2380]

RGEM blasts southern Iowa from just about i80 and south.

[Tom]

Winter Storm Watches hoisted from I-80 on north in N IL!

[East Dubzz]

I expect the GFS to cave this run. Quite disappointing, but whatever I suppose. Still early. Just hope to see things stay active!

[jaster220]

It may be seeing a warm layer and thus limiting snow production  At this point, I would pay attn where this pivot happens and where the warm tongue approaches near your area.  It seems to me the higher rez models are bringing it very close to your back yard.  With that in mind, where this rain/snow line sets up, I'm seeing pretty good signals that thunderstorms may get entrenched into the cold sector...Thundersnow???  Man, look at this HRRR and higher rez NAM almost creating a trowel feature towards the end of the run.  Models are suggesting intensification as it approaches the lower GL's.  The trough looks like it may be trying to go neg tilt as it heads up our way...remember, this is where the LRC's long term long wave trough has set up and where systems have intensified so I think this last minute trend is our friend.

 

 

 

 

 

 

Thx for your insights buddy. As for the portion I underlined, I have to reach way way back to when I was like 21 y.o. to remember the days when we had this set-up. A storm starting as rain, then strengthening in the region and causing a rapid transition to +SN. And then it was never in Nov! I was in SEMI then and the results were normally 4-6" of concrete mixer stuff. The density of the snow made roads much worse tho and with it happening so quickly plow crews didn't keep up thus on an impact level it actually was worse imho than a 6-8" traditional warned storm. Getting kinda pumped again after deflation via the GooFuS models all day yesterday. Gotta put the final touches on my Christmas lighting I did yesterday.

[jaster220]

Winter Storm Watches hoisted from I-80 on north in N IL!

 

Congrats on your headlines amigo! GRR shoulda just issued an SWS overnight and waited for this morning's suite. but, tis GRR - sigh

[Tom]

Thx for your insights buddy. As for the portion I underlined, I have to reach way way back to when I was like 21 y.o. to remember the days when we had this set-up. A storm starting as rain, then strengthening in the region and causing a rapid transition to +SN. And then it was never in Nov! I was in SEMI then and the results were normally 4-6" of concrete mixer stuff. The density of the snow made roads much worse tho and with it happening so quickly plow crews didn't keep up thus on an impact level it actually was worse imho than a 6-8" traditional warned storm. Getting kinda pumped again after deflation via the GooFuS models all day yesterday. Gotta put the final touches on my Christmas lighting I did yesterday.

You are likely going to be re-living those golden years of the past my friend.  What a turnaround in just 24 hours...not to shabby, right???  Same here, I just got back from the stores and purchased some more outdoor LED lights/icicles and plan on putting the rest up later this afternoon.  Need to eat and take a power nap beforehand though...woke up way to early today!

[hlcater]

It's not just the NAM, nearly every model is now seeing what the Euro/Ukie have been showing over the past couple runs.

Yes and I recognize that, but the NAM doing anything shouldn’t be sufficient justification as it’s had every solution under the sun the past 8 runs.