Pre-Christmas (Dec 21-23rd) Winter Storm

[mimillman]

18z euro will be less amped again.

Onset of precipitation keeps getting delayed a few hours each run as WAA snows shift well north out of the area. We are dealing with mostly a Thursday evening into Friday system now and yes, the scale may be large but we are at least 78 hours away from any meaningful precip. Still think a bit premature to hoist watches.

[RogueWaves]

On 12/2/2022 at 6:53 PM, RogueWaves said:

Not too much longer and it'll be so busy in here everyone will forget all about the snooze fest. 

Bump

[SchaumburgStormer]

6 minutes ago, mimillman said:

18z euro will be less amped again.

Onset of precipitation keeps getting delayed a few hours each run as WAA snows shift well north out of the area. We are dealing with mostly a Thursday evening into Friday system now and yes, the scale may be large but we are at least 78 hours away from any meaningful precip. Still think a bit premature to hoist watches.

18z is still a major blizzard in Chicago on a extremely heavy travel day. 

[Frog Town]

Anyone thinking there could be a secondary low development further south??  Could explain why less moisture is making it north.  

[SolidIcewx]

18Z vs 12Z euro with temps

[Baum]

21 minutes ago, mimillman said:

18z euro will be less amped again.

Onset of precipitation keeps getting delayed a few hours each run as WAA snows shift well north out of the area. We are dealing with mostly a Thursday evening into Friday system now and yes, the scale may be large but we are at least 78 hours away from any meaningful precip. Still think a bit premature to hoist watches.

Of course it's a risk. But given the potential and the time of year you need to get the word out. It was a concerted effort to make the public aware. The normal tom,dick, and jenny isn't  looking at the 18Z European model. Let's face it a widespread 2-5" event with below zero wind chills and 45mph winds the days before Christmas is a major hazard for joe public.

[Imneversatisfied]

What are the odds the slp locations move east due to such a strong arctic front push?

[SchaumburgStormer]

24 minutes ago, Baum said:

Of course it's a risk. But given the potential and the time of year you need to get the word out. It was a concerted effort to make the public aware. The normal tom,dick, and jenny isn't  looking at the 18Z European model. Let's face it a widespread 2-5" event with below zero wind chills and 45mph winds the days before Christmas is a major hazard for joe public.

Yes. And even the less amped 18z euro is an 8-10” storm area wide. 

[weathafella]

2 hours ago, RCNYILWX said:

It's honestly hard to get huge QPF as snow in this area. To get 1" liquid equivalent in a snow system is pretty high end, if you go by the top 5 Chicago snowstorms posted above and at least GHD I and II had lake enhancement in those totals.

So while the top end QPF amounts have come down since yesterday and there's a meteorological reason for it, it also represents coming down closer to reality. The widespread 2"+ precip. totals from the GFS last night are basically unheard of in this part of the Midwest in a snowstorm, with the exception of the January 1967 blizzard.

 

Thanks!  I notice 18z euro showed what seemed to me lake enhancement later.  

Good luck-wish I could come but I’m home recovering from covid.  
 

I did send this to 15 Chicagoland relatives:

 

“Heads up everyone.  A once a decade blizzard is likely later this week in Chicagoland.  If I didn't have a rebound of Covid we'd be coming to experience it.  Any travel after Wednesday probably will need to be rearranged.  It's going to be very cold later in the storm-be careful!”

[mimillman]

47 minutes ago, SchaumburgStormer said:

18z is still a major blizzard in Chicago on a extremely heavy travel day. 

I didn’t say it wouldn’t be. My point was regards to timing. And for the record I actually prefer the 18z track and low placement both for better ratios and because defo band snows are always further northwest than progged 

[omega]

13 minutes ago, Imneversatisfied said:

What are the odds the slp locations move east?

The quickest way to determine that is to eyeball trends, and whether or not you're still in the game is looking at all of the trends in the ensembles. Here are all of the runs yesterday and today:

GFS

ECMWF

CMC

Overall, it seems like the models are convering on the low tracking from IL into MI. The models will keep bouncing around within that region until we get a better handle on upstream features, but I don't personally expect massive jumps at this point. 

[cyclone77]

15 minutes ago, Imneversatisfied said:

What are the odds the slp locations move east due to such a strong arctic front push?

Nice user name.  I feel like I should change mine to Imneversatisfied2 lol.

[CheeselandSkies]

1 hour ago, sbnwx85 said:

I have yet to cover a true blizzard while working in TV news. We’re already asking crews who were off Friday to come into work. I usually work 1 pm to 10 pm, but I have a feeling I’ll be starting my Friday much earlier and ending it sometime late on Saturday.

Are you on-air or behind the scenes?

I work behind the scenes on the morning show at a local station here in Madison.

[AppsRunner]

The ECM ensemble continue a slightly weaker/slower evolution through the Ohio valley and is at least a slight jog east. The STL-IND-DTW track feels like a reasonable middle ground for now. 

I'll still take the over for ALEK. 

[SolidIcewx]

I took a PTO day on Thursday just so I can track. Can’t wait for the pot of coffee or more

[Stevo6899]

2 minutes ago, SolidIcewx said:

I took a PTO day on Thursday just so I can track. Can’t wait for the pot of coffee or more

Track what? lol. Ain't nothing to track when you're east of the low. I wouldn't bank on wrap around precip either. But hey i guess if you love weather, it could be fun to track others' snowstorms.

[Imneversatisfied]

Thanks for the maps Omega. Def helps visualize the possibilities. Going to start prepping to hunker down for a few days just in case. Just happy to have a white Christmas really.

[Kaner88]

So from what I gather, Chicago has a floor of about 3" (east jump at the last minute + typical QPF shaving as we approach event) and a ceiling of about 24" (more moisture than progged, pristine track, thundersnow, the works).

Do not envy LOT right about now. Or any WFO trying to communicate about a possible blizzard right before Christmas.

[RCNYILWX]

Yes. And even the less amped 18z euro is an 8-10” storm area wide. 

And still snowing at the end of the run. The precip type product on Pivotal Weather is a bit stingy on the western edge of the precip shield, with forecast soundings suggesting it's more likely to be a bit west of I-39 on that run. Meanwhile over Chicago at 12z Friday, a deeply saturated profile with a temperature of -3F and ~950 mb winds of 50 kts.

[sbnwx85]

29 minutes ago, CheeselandSkies said:

Are you on-air or behind the scenes?

I work behind the scenes on the morning show at a local station here in Madison.

Behind the scenes. Assignment Editor nightside. I used to be on air for a radio station in Jacksonville, IL. I covered one blizzard warning there in 2012 but it was for quick hit that brought blizzard conditions for about two hours. It was exciting but I’m really looking forward to a longer-duration blizzard.

[mississaugasnow]

18 minutes ago, Stevo6899 said:

Track what? lol. Ain't nothing to track when you're east of the low. I wouldn't bank on wrap around precip either. But hey i guess if you love weather, it could be fun to track others' snowstorms.

Parts of Southern Ontario and WNY look decent on the east side. 

[SolidIcewx]

Let’s see the nam do nam things

[Kaner88]

Something interesting (to me, maybe not synoptically) is how recent runs of model guidance in general have been "breaking up" that broad TPV lobe in southern Canada from one big vort to what looks more like two: one in the Great Lakes vicinity, and then of course our storm system. Curious if anyone more knowledgeable believes this to be something impactful on the final track, or perhaps it's immaterial to the final track.

 

GIF of the last few NAM runs' 500mb attached.

[ChiTownSnow]

1 minute ago, Kaner88 said:

Something interesting (to me, maybe not synoptically) is how recent runs of model guidance in general have been "breaking up" that broad TPV lobe in southern Canada from one big vort to what looks more like two: one in the Great Lakes vicinity, and then of course our storm system. Curious if anyone more knowledgeable believes this to be something impactful on the final track, or perhaps it's immaterial to the final track.

 

GIF of the last few NAM runs' 500mb attached.

Is that what is allowing the initial front end wave to go so far north? 

[Chicago Storm]

9 minutes ago, Kaner88 said:

Something interesting (to me, maybe not synoptically) is how recent runs of model guidance in general have been "breaking up" that broad TPV lobe in southern Canada from one big vort to what looks more like two: one in the Great Lakes vicinity, and then of course our storm system. Curious if anyone more knowledgeable believes this to be something impactful on the final track, or perhaps it's immaterial to the final track.

 

GIF of the last few NAM runs' 500mb attached.

That is most definitely one of the changes, actually briefly mentioned a change in Canada earlier...and that's it. As you can see in your animation, that alters heights ahead of the main trough/wave.

[Kaner88]

2 minutes ago, Chicago Storm said:

That is most definitely one of the changes, actually briefly mentioned changes in Canada earlier. AS you can see in your animation, that alters heights ahead of the main trough/wave.

Appreciate the response. Looks to me like the change has resulted in stronger downstream ridging around the OV area, which ought to favor that further west track, does that sound about right?

[Chicago Storm]

1 minute ago, Kaner88 said:

Appreciate the response. Looks to me like the change has resulted in stronger downstream ridging around the OV area, which ought to favor that further west track, does that sound about right?

It pumps up better ridging immediately ahead of the trough, but further ahead things end up a bit flatter overall. This, along with changes in the Pacific/West Coast, are some of the reasons we have seen a slight shift east in the track (And other changes).

[ChiTownSnow]

So..Uh...about that NAM.  

[Kaner88]

1 minute ago, ChiTownSnow said:

So..Uh...about that NAM.  

It used a special Alek sampling; Chicago will not be denied 5" on the dot

[SolidIcewx]

4 minutes ago, ChiTownSnow said:

So..Uh...about that NAM.  

NAM had some drinks