Midwest & Great Lakes November 20-21st Snowstorm

[East Dubzz]

06z NAM...a blip of 12" near East Dubzz...

I'm actually in rock island for school, but still some good looking totals around there.

[Tom]

Check out that beautiful pink color in SEMI.

Yup, not a bad system for a lot of us on this sub-forum.  Couldn't ask for a better storm to track in late November.

[Tom]

I have to go get another wide push shovel today. Seeing salt trucks loading up this morning!

 

4km NAM showing that lake effect signature from Racine and snaking all the way to Kane County!

 

http://maps3.pivotalweather.com/models/namhires/20151120/12Z/f42/accsnowmw.png

BTW, what do the Delta T's look like later tonight???  

[james1976]

Loving the looks of the models this morning! Lets get this party started!

[james1976]

Mesoscale disco for heavy snow
http://www.spc.noaa.gov/products/md/md1986.html

[WBadgersW]

RGEM definitely cut back on the totals on the Northern fringe.

 

[Niko]

Yup, not a bad system for a lot of us on this sub-forum.  Couldn't ask for a better storm to track in late November.

Exactly, this is a bonus for this time of the year. I believe someone on this board will approach a foot or more. It all depends on where that heavy band sets up. 

[Niko]

Loving the looks of the models this morning! Lets get this party started!

James, you will do great also. I can see you getting 4-9inches. Enjoy!

[Tom]

Exactly, this is a bonus for this time of the year. I believe someone on this board will approach a foot or more. It all depends on where that heavy band sets up. 

12z GFS just did SEMI good!  Looks like the 12z runs thus far have shifted south for your area...6-10" looking likely now from DTWand NW burbs.

[Tom]

GFS picking up on 3-6 hours of Lehs in NE IL...looks like from 10-4pm on Sat might be a period of enhanced snowfall for McHenry/Kane/DuPageLake/Cook counties...getting interesting!

[Niko]

12z GFS just did SEMI good!  Looks like the 12z runs thus far have shifted south for your area...6-10" looking likely now from DTWand NW burbs.

That looks awesome!!! Somebody turn on the Disco lights please.   

[Tom]

James, are you seeing snow yet?  Radar seems to be showing a band of snow heading your way,

[6789]

Really excited for such an early storm, it's almost like it wanted to make sure it would miss the weekly commutes of people and give everyone a little "taste," of winter when they can enjoy it on the weekend. Really can't remember a November storm this big since I was a kid then again I'm only 19 lol. Hopefully this season brings a lot of these! I think my favorite part is the fact that it'll be 50 and sunny on Thanksgiving, I absolutely love when the weather shifts like this. 

[Iowa2015]

quote name="Tom" post="91200" timestamp="1448033524"]BTW, what do the Delta T's look like later tonight???

Wow Love this modal lock it in has 8 inches with a red blip 11 inches real close

[WBadgersW]

Recent trends have me a bit worried, but it's becoming a more nowcasting situation. I wouldn't be surprised if this storm takes a more Southern track like the Euro.

[Tom]

quote name="Tom" post="91200" timestamp="1448033524"]BTW, what do the Delta T's look like later tonight???

Wow Love this modal lock it in has 8 inches with a red blip 11 inches real close

Delta T Change in temperature. 1) A simple representation of the mean lapse rate within a layer of the atmosphere, obtained by calculating the difference between observed temperatures at the bottom and top of the layer. Delta Ts often are computed operationally over the layer between pressure levels of 700 mb and 500 mb, in order to evaluate the amount of instability in mid-levels of the atmosphere. Generally, values greater than about 18 indicate sufficient instability for severe thunderstorm development. 2) The difference in temperature between the surface of a lake and 850mb, typically used to determine lake effect snow potential.

[Tony]

GFS picking up on 3-6 hours of Lehs in NE IL...looks like from 10-4pm on Sat might be a period of enhanced snowfall for McHenry/Kane/DuPageLake/Cook counties...getting interesting!

This will be the exciting part of the storm for our area. If everthing lines up just right we could really see some enhanced totals even out this way in the western burbs. Delta T'S should be prime especially with the unusually warm waters.

 

I can see Geos really getting hammered on this one.

[NEJeremy]

15Z HRRR now down to .4" of snow here in Omaha. Looks good in Iowa- shows 6" for Des Moines and 11.5" for Fort Dodge. This is just through 06Z tomorrow morning.

[Tom]

From here on out its going to be a nowcast event...model consensus is there...I'll just stick the 12z GGEM snowfall map below...

 

http://www.tropicaltidbits.com/analysis/models/gem/2015112012/gem_asnow_ncus_10.png

[westMJim]

This will be the exciting part of the storm for our area. If everthing lines up just right we could really see some enhanced totals even out this way in the western burbs. Delta T'S should be prime especially with the unusually warm waters.

 

I can see Geos really getting hammered on this one.

With the lake as warm as it still is. Do not be too surprised if the heaviest lake effect happens about 15 to 20 miles inland with more maybe some rain right at the lake shore.  

[East Dubzz]

UKMET: 

[westMJim]

Now with our eyes on the weekend snow event. First off with the warm ground temps we may have up to 8” fall but may very well not have 8” acclimate. With the forecast of 5 to 8” of snow the first thing to know is that (one day) snow fall amounts of 5” or more do not happen in Grand Rapids ever November and if Grand Rapids were to get 8” Well for starters that does not even happen many winters and in November the times it happened are 2014, 2004, 2000,1991 and then in October 1967. Of the years we had the above November snowstorms only 2004 (weak and 1991 moderate) were El Nino years with 2000 and 1997 being La Lina years.  Will have a better list after we know how much snow falls on Saturday

[WBadgersW]

So the Southern trend continues. GEM, ARW, and NMM are all looking more similar to the GFS.

 

It's not very often this area gets a snowstorm in November, let alone have it South of me. Usually they curve to the North and bring me rain.

[Money]

Chicagos on a hot streak last couple years

[Sleather]

Wow. Plumes for Joliet have risen from abt 5" to abt 9" in the last six hours. I'm skeptical.

[WBadgersW]

Milwaukee still favoring a Northern track

 

 

 

.UPDATE...OVERALL FORECAST IS IN GOOD SHAPE WITH INITIAL LOOK AT
12Z GUID. UPPER TROUGH WILL CARVE OUT ACROSS THE MID MISS VLY WITH
NEWD CURVE TO UPPER SPEED MAX. LEFT ENTRANCE REGION OF THIS SPEED
MAX FAVORS A MORE NWD SFC LOW DEVELOPMENT. LOCALLY WE HAVE SEEN
THAT THE WARMER GREAT LAKES WATERS TENDS TO DRAW THESE LOWS CLOSER
AS WELL. WE ARE ALSO SEEING THE MODELS SHOW AN INCREASED RISK FOR
LAKE ENHANCEMENT ESPECIALLY LATER TONIGHT INTO SATURDAY MORNING AS
DELTA T INCREASES TO 16C WITH A FAVORABLE TRAJECTORY IN PLACE IN
THAT WINDOW OF TIME. STILL SOME CONCERN THOUGH WITH MESO MODELS
TRENDING HIGHER QPF AMOUNTS SOUTH OF WI INTO THE EVENING HOURS AND
WE ALSO THINK SOME DRY AIR AT THE OUTSET WILL CUT DOWN ON SOME
INITIAL ACCUMS. WE WILL CONTINUE TO LOOK OVER THE 12Z DATA...COORD
WITH WPC AND SURROUNDING OFFICES BEFORE CHANGING ANY AMOUNTS. THE
NORTHWEST/SOUTHEAST GRADIENT STILL LOOKS GOOD...ESPECIALLY WITH
THE ADDED LAKE EFFECT/ENHANCEMENT POTENTIAL. NO CHANGE TO HEADLINES
AT THIS TIME. CONFIDENCE IS A BIT HIGHER IN THE SOUTHERN AND EASTERN
PORTION OF THE WARNING AREA.

[jaster220]

12z GFS just did SEMI good!  Looks like the 12z runs thus far have shifted south for your area...6-10" looking likely now from DTWand NW burbs.

 

Don't forget mby - lol 

 

Some of these maps are getting crazy with their "hotness" over here in SCMI.  Similar to the last 24-36hr bumps in QPF we saw with the Feb Big Dog. All time record biggest 1st snow is like 9" for KBTL (nearest official site west of mby) and this could be bigger if trends remain.

[Tony]

Mike Hamernik @MikeHamernik

Snowfall rates of 3"-4" *per hour* in a narrow band over SE SD & NW Iowa... https://twitter.com/wxspinner89/status/667752915419926529 

[Geos]

BTW, what do the Delta T's look like later tonight???  

 

Like 16-18°C. And that's between the lake temperature and the 850mb level.

[Geos]

UKMET: 

 

I can see a sliver of 30mm over my area! 

People are getting really excited to see the snow and not to see the snow around here! lol

[Tom]

12z Euro...holding strong...looks similar to the Ukie...

 

@ Geo's, its painting a sliver of 1"-1.2"qpf just off shore by you!

[Geos]

It's amazing how consistent the LES signal is getting and a lot of models now agree on the location!

 

This was 1 hour ago: 8" of snow in Sioux Falls and it's still snowing!

 

Scratch that: now 10"!

[FV-Mike]

 

Mike Hamernik @MikeHamernik

Snowfall rates of 3"-4" *per hour* in a narrow band over SE SD & NW Iowa... https://twitter.com/wxspinner89/status/667752915419926529 

 

Yep, and he also tweeted out 8 inches down ins Sioux Falls, SD. Snow is ripping

[East Dubzz]

Euro looks good as well, just not as strong on the southern edge, but man 6" looks like a real possibility and that's what I wanted at the beginning

[Tom]

Clouds beginning to thicken, 39F temp...just finished my yard work...on to the store to buy a new shovel...

 

Impressive radar returns near Sioux Falls...that band is heading almost due east into N IA...

[Geos]

Clouds beginning to thicken, 39F temp...just finished my yard work...on to the store to buy a new shovel...

 

Impressive radar returns near Sioux Falls...that band is heading almost due east into N IA...

 

Same here, but I'll be getting a new shovel at 5 pm.

 

Just saw a plow truck go by. Getting in position I guess!

 

Wide map of the EURO snowfall.

 

[jcwxguy]

It's amazing how consistent the LES signal is getting and a lot of models now agree on the location!

 

This was 1 hour ago: 8" of snow in Sioux Falls and it's still snowing!

 

Scratch that: now 10"!

you would think the NWS would upgrade the WWA 

 

edit: part of the city is in a WSW, but most is not

[james1976]

Just got home....snowing very hard! Already an inch and the roads and pavement are getting covered. Ground temps are good to go!

[james1976]

http://mesonet.agron.iastate.edu/data/lsr_snowfall.png?1261154738?area=IA_statewide

[james1976]

It is relentless here. Still coming down hard with big flakes. Ill get a measurement in a while.