November 20-21 Early Season Snowstorm

[Gilbertfly]

Winter Storm Warning extended down to Will County now.

 

 

 

P&C lowered to 1-2

 

 

 

 

starting to rip pretty good...

 

KALO 202006Z 07008KT 1/2SM R12/3000V4000FT SN FZFG FEW006 OVC014 M02/M03 A3017 RMK AO2 P0001 T10171028

[Jonger]

gonna be a shame if this is rain

I hope you enjoyed the above average November. It "might" cost ya.

Who knows. What time does this kick off in Chicago?

[Gilbertfly]

MBY....

5 to 9

with 7.2 in the hourly

 

via LOT

[snowcaine]

Current temp is 40

Dewpoint is 16

Humidity 38%

 

It's going to take time to saturate.

 

Nice spread

[OHweather]

Interesting that DTX balked on the warning and went advisory for their entire CWA instead.

[Hoosier]

Where do you pull these soundings from?

 

 

I got that from Plymouth

 

 

http://vortex.plymouth.edu/make.html

 

 

Model forecast soundings ---> individual soundings

[Gilbertfly]

gotta think that dynamic cooling will help some on the edge of the mix precip with some of the rates being portrayed....

 

 

1/4 mile obs popping up now through central iowa in spots

[HillsdaleMIWeather]

GRR and DTX opted for Winter Weather Advisories

[Wickedtwister28]

Interesting that DTX balked on the warning and went advisory for their entire CWA instead.

GRR did same thing but they've been burned bad in past so this is just them covering their rear ends. It's easier to upgrade to a warning then downgrade. You look worse lol

[Wickedtwister28]

GRR has advisory for 3-8 inches of snow... So to sum it up they have not idea and either way they can't get "burned"

[OHweather]

GRR did same thing but they've been burned bad in past so this is just them covering their rear ends. It's easier to upgrade to a warning then downgrade. You look worse lol

When I posted GRR's advisory hadn't quite shown up on the maps but yes I see it now. I'm really not a fan of conservative forecasting to cover your rear when there's been agreement on a swath of warning criteria snows through both CWA's for several runs and no real reason think the whole thing will fall apart. It's also the first accumulating snow of the season. But I digress.

[SchaumburgStormer]

Looks like temps will underachieve. Been stuck at 36 for a while, with 41 in the P&C. 21 dew at the moment. Radar returns overhead are virga.

[HillsdaleMIWeather]

Agreed, being chicken during the first snow of the season is a bad idea. Maybe IWX actually will do it, I doubt it though

[HillsdaleMIWeather]

The Weather Channel app has me with 8-12... I see they liked the GFS

[Wickedtwister28]

When I posted GRR's advisory hadn't quite shown up on the maps but yes I see it now. I'm really not a fan of conservative forecasting to cover your rear when there's been agreement on a swath of warning criteria snows through both CWA's for several runs and no real reason think the whole thing will fall apart. It's also the first accumulating snow of the season. But I digress.

GRR seems so hard to impress. If you ever read their forecast discussions they like to use lots of technical terms. It can sometimes be fun but a lot of the time it's annoying. I know in the summer forecasting thunderstorms crossing the lake will make them pull their hair out trying to predict what the lake will do

[WxMatt21]

Agreed, being chicken during the first snow of the season is a bad idea. Maybe IWX actually will do it, I doubt it though

 

I'd be shocked if IWX didn't throw up at at least an advisory for half of the forecast area (I think the cut off would be Allen County IN). 1-3" for the first snow of the season should be more than enough to push out an advisory. 

[Jonger]

Agreed, being chicken during the first snow of the season is a bad idea. Maybe IWX actually will do it, I doubt it though

Over or under on when this gets upgraded to WSW? 10am Saturday.

[Chicago Storm]

18z 4km NAM...

[Thundersnow12]

13" report in Sioux Falls 

[DLMKA]

All snow in DBQ, sticking to non-paved surfaces.

[flyfisher7]

Over or under on when this gets upgraded to WSW? 10am Saturday.

over - noon

[vortex]

Gil was down playing storm yesterday with the infamous "ground too warm."

 

Update #1, 12 PM: First, puddles were frozen around mid-morning
today. That means that the ground is not as warm as earlier feared.
Second, we are now seeing widespread 6"-10" snowfall reports as of
11:30 AM in northwest Iowa and southeastern South Dakota, in areas
that were just in the 70s a few days ago. With no Gulf moisture
to work with, this system is going to put out a narrow but very
intense band of heavy snow. Seeing the amounts upstream, and the
radar echoes expanding and intensifying, the data reveals the
fangs of this system: it's going to give much of our area
heavier snow than I expected this morning. I have bumped up
amounts accordingly.

 

[HillsdaleMIWeather]

NAM is still having QPF issues, I see. Totals are low in Iowa.

[mimillman]

I got that from Plymouth

 

 

http://vortex.plymouth.edu/make.html

 

 

Model forecast soundings ---> individual soundings

 

Thanks for this.

 

I checked the NAM soundings for MDW, and it seems as though the deepest the warm layer ever gets is 986mb. Like you said before, it would have to be an inferno on the surface for the rain to verify on the hi-res guidance. 

[HillsdaleMIWeather]

IWX opted for WWA, didn't raise accumulations

[Hoosier]

Here are the 6+ inch November storms that I have for Chicago.  This doesn't include anything that may have started in November and spilled into December.  Also, it snowed on surrounding dates in a few of these years (1940, 1975, 1978) but it appears it was separate storms, so I excluded the snow from those surrounding dates.

 

1895 is particularly impressive as I think the official observations were in/near downtown in those days.

 

 

6" or greater November snowstorms for Chicago:

 

11/25-26/1895:  12.0"

11/26-27/1975:  8.6"

11/6/1951:  8.0"

11/26-27/1940:  6.4"

11/27-28/1891:  6.0"

11/26-28/1978:  6.0"

 

 

Now, the heaviest calendar day November snowfalls for Chicago:

 

11/6/1951:  8.0"

11/26/1975:  7.5"

11/26/1895:  7.0"

11/27/1891:  5.8"

11/26/1940:  5.7"

11/26/1950:  4.7"

11/24/2004:  4.3"

11/5/1896:  4.0"

 

[Chinook]

NAM is still having QPF issues, I see. Totals are low in Iowa.

I am seeing that Mason City IA is reporting both 2" and 4" from spotters (not sure which is right.) Visibilites are 1 mile or lower from Mason City to Dubuque/Platteville WI and much of northern Iowa, so this indicates some accumulation- maybe 1/2" per hour maybe a little higher.

[A-L-E-K]

1895 is a beast and probably safe

 

the rest are in play

[Chicago Storm]

Here are the 6+ inch November storms that I have for Chicago. This doesn't include anything that may have started in November and spilled into December. Also, it snowed on surrounding dates in a few of these years (1940, 1975, 1978) but it appears it was separate storms, so I excluded the snow from those surrounding dates.

1895 is particularly impressive as I think the official observations were in/near downtown in those days.

6" or greater November snowstorms for Chicago:

11/25-26/1895: 12.0"

11/26-27/1975: 8.6"

11/6/1951: 8.0"

11/26-27/1940: 6.4"

11/27-28/1891: 6.0"

11/26-28/1978: 6.0"

Now, the heaviest calendar day November snowfalls for Chicago:

11/6/1951: 8.0"

11/26/1975: 7.5"

11/26/1895: 7.0"

11/27/1891: 5.8"

11/26/1940: 5.7"

11/26/1950: 4.7"

11/24/2004: 4.3"

11/5/1896: 4.0"

You literally beat me to posting this by about 5min.

[Stebo]

Interesting that DTX balked on the warning and went advisory for their entire CWA instead.

I don't understand why, 5-7" which is right on the line of a warning, not to mention high impact first snowfall with the worst coming in the span of 6 hours tomorrow evening. There is certainly justification for a warning for north of the city.