Nov 28-30th Post Turkey Day Winter Storm

[michsnowfreak]

3-6" seems like a good call for Detroit.

[Chambana]

4.6” final call. Chicagoland looks locked and loaded for a solid 6-9” event

[michsnowfreak]

1 hour ago, AWMT30 said:

Solid start to the models today! A nice Chicago to Detroit sweeping Winter Storm with 6-10" 

Chicago saw under 20 last winter. I dont mind that they'll get more than us this storm. Regardless looks like a widespread advisory to warning criteria snowstorm. Thats on top of the early November 9-10 snowfall and cold as far as the eye can see...excellent start to winter!

[fluoronium]

I've never used the RRFS for snow before but it's interesting to see it hinting at thundersnow.

I have noticed that the lightning algorithm on the HRRR has been completely worthless for predicting thundersnow (or at least the algorithm CoD uses)

[cyclone77]

Can't recall any other warning criteria events here when the winds were from the southeast predominately.  Gonna be kind of strange lol.

[ChiTownSnow]

Seems like the higher end totals may depend o solely on instability and thunderstorm like convection that happens locally.  

[donsutherland1]

For reference:

The 33.5 cm snowfall at Toronto on November 30, 1940 is the biggest daily snowfall on record for November. The 10.0" for Milwaukee on November 30, 1940 is the second biggest daily snowfall on record for November.

[hawkeye_wx]

The Euro is stronger/sharper with the shortwave at 500 mb than the rest of the models.  I was expecting the 12z run to fade south and weaker just a bit, but it actually ticked farther north.

Here are the resulting snow maps for the south UK, middle GFS, and north Euro.

[Radtechwxman]

4 minutes ago, hawkeye_wx said:

The Euro is stronger/sharper with the shortwave at 500 mb than the rest of the models.  I was expecting the 12z run to fade south and weaker just a bit, but it actually ticked farther north.

Yeah it definitely is. I wouldn’t want it anymore north than that. Hugs that mixing line right against me. Oof. My biggest worry is the marginal temps and ratios during day Sat. If rates are high enough it will help mitigate it somewhat but I do anticipate some level of melting and compaction. Hoping that warm nose can stay south enough to avoid a changeover. But that sfc low does get pretty north. 

[ILSNOW]

Happy Thanksgiving to all!!!!

[Baum]

1 hour ago, ILSNOW said:

Happy Thanksgiving to all!!!!

I’ve decided to withhold my reply until Saturday evening 

[Chicago Storm]

Today’s trend has been to reverse yesterday’s trend.

Yesterday’s we saw guidance come in less phased, less amped and flatter with the main wave…thus, weaker, south and drier. Today’s trend reversed all of that.

[sbnwx85]

Could cash in on lake effect bonus Sunday. 12”+ in play. 

[cyclone77]

HRRR 18z is a beautiful sight to behold.  

[Baum]

7 minutes ago, Chicago Storm said:

Today’s trend has been to reverse yesterday’s trend.

Yesterday’s we saw guidance come in less phased, less amped and flatter with the main wave…thus, weaker, south and drier. Today’s trend reversed all of that.

Hold.

[Sciascia]

4 minutes ago, cyclone77 said:

HRRR 18z is a beautiful sight to behold.  

Let’s behold it together (thru noon Saturday)

[Harry Perry]

Winter storm watch for the entire GRR CWA. Local P&C showing 8” and still snowing by Sunday. Looks like gusty winds in the 30-40 mph range, so blizzard conditions at times.
 

Still some time for the rug to get yanked but I feel pretty confident in a solid 6-10”+ throughout the sub. 

 

[andyhb]

500 mb evolution with this does remind me a good deal of a slightly less impressive version of GHD II. Trough/jet streak matures in a very similar way and the thermos aren't terribly far off from that either. More likely to taper out with eastward extent though.

[hawkeye_wx]

I would, of course, love for the 18z HRRR to be correct, but it is likely too strong and juiced.  It has a 1004 mb low, whereas the globals have a 1008-1012 mb low.  This HRRR run would probably finish with 16+" in Cedar Rapids, which I very much doubt.  Half of that is more likely.  The CAMs will probably come back to earth as the start approaches.

[Harry Perry]

1 minute ago, andyhb said:

500 mb evolution with this does remind me a good deal of a slightly less impressive version of GHD II. Trough/jet streak matures in a very similar way and the thermos aren't terribly far off from that either. More likely to taper out with eastward extent though.

Ironically enough I was going to mention this myself as well. Definitely some similarities. 

[jlauderdal]

Let’s behold it together (thru noon Saturday)

Eye candy that won't materize, GFS does this in the tropics on a regular basis. Heavy rain at my place ahead of a cold front, last rain and 80s I will see for a few days. I'm holding my 7.5 prediction for Western burbs. One more shot to adjust tomorrow.

[Chicago Storm]

500 mb evolution with this does remind me a good deal of a slightly less impressive version of GHD II. Trough/jet streak matures in a very similar way and the thermos aren't terribly far off from that either. More likely to taper out with eastward extent though.

This is a very good and valid point.

[weathafella]

Clown range 18z NAM shows a trend to have better mid levels.  That can really improve output regardless of modeled qpf (which is decent as is).

[andyhb]

6 minutes ago, Chicago Storm said:

This is a very good and valid point.

IIRC that wave had a deepening trend closer to verification as well as the PV lobe became better resolved, I remember having some back and forth with @RCNYILWX about it at the time.

The issue this time is that the upstream ridge isn't quite as amplified as that, and there's a bit more phasing required here for a higher end outcome.

[hawkeye_wx]

Can always count on the 18z NAM/3kNAM to go extra weenie.

[hlcater]

bring it

[KeenerWx]

Yanked some stats for Kankakee County because they have done especially incredible compared to climo this November. While I don’t live there, I can geek out about random stats. Now, consider that this data comes from COOP reports. It’s justified to question some data especially as we reach further back. But it’s what we’ve got. Pulled 1925-2025 from reporting locations nearest to Kankakee. 

Top 5 Snowfall: Month of November

Some locations in Eastern Kankakee County have already notched 2025 as #1 or will soon do so. The rest of the county will likely place at #2, with real possibility of taking #1 if things break right.

1951 - 12.3”

1959 - 9.8”

1932 - 7.2”

1950 - 7.0”

2015 - 6.3”

Gamma distribution would suggest roughly along the following periods for each breaking point in total November snowfall:

8” - 1 in 35 years

12” - 1 in 75 years

16” - 1 in 150 years

20” - 1 in 300+ years

Needless to say, the upcoming snowstorm will likely push the county into historic+ proportions for the month of November. Especially the eastern portions of the county where the highest breaking points are achievable.

Top 5 Snowstorms: Month of November

Here again areas in eastern parts of the county already notched a likely #1. The rest of the county can put these on watch to surpass. 

November 6-7, 1951 - 9.0”

November 12-14, 1959 - 8.0”

November 15-16, 1932 - 7.2”

November 29, 1942 - 6.0”

November 21-22, 2015 - 6.3”

 

Finally, it looks nearly certain that the county will grab two 4”+ events in the month of November, which hasn’t ever happened from what I gathered. 
 

Soliloquy over. Carry on. 

[frostfern]

5 hours ago, Harry Perry said:

Winter storm watch for the entire GRR CWA. Local P&C showing 8” and still snowing by Sunday. Looks like gusty winds in the 30-40 mph range, so blizzard conditions at times.
 

Still some time for the rug to get yanked but I feel pretty confident in a solid 6-10”+ throughout the sub. 

 

I don’t know what kind of ratios this is.  I prefer to look at 10:1 and bump it up a little in my head.  It’s hard to get 15:1 or better this time of year without lake enhancement.  WAA snow tends to be somewhat denser, at least in my area with E wind off the land.

[andyhb]

HRRR continues to be very impressive, albeit likely overdone. Verbatim would likely mean some pockets of 12-18" over IA and N IL/S WI.

[Stebo]

Looking good time to lock it in