Midwest & Great Lakes November 20-21st Snowstorm

[Iowa2015]

I'm going with the majority Gem Gfs Nam as most system have took the southerly track love for those totals to verify it be amazing first snowstorm to kick off the winter season.

[Money]

Nam coming in stronger

[gosaints]

Oh  how I love when the NAM acts like the NAM

[jaster220]

NAM Map pls..

[WBadgersW]

NAM picking up on some LES?

[Tony]

NAM looks like it weakens the storm as it heads east. Different setup compared to all the other models.

 

Edit: It is the NAM but I expected just the opposite.

[Geos]

NAM is weaker for some reason...

 

 

These two maps don't jive at all if you compare scales.

 

[Money]

NAM is weaker for some reason...

 

http://www.tropicaltidbits.com/analysis/models/namconus/2015111818/namconus_asnow_ncus_29.png

 

NAM is showing 12+ in southern Minny.

[Geos]

 

NAM is weaker for some reason...

 

 

NAM is showing 12+ in southern Minny.

 

 

As I added above - the scale on this map is off. Instant weather maps has the correct accumulations.

[chances14]

probably has to do with the fact tropical tidbits uses 10:1 ratios while instantweather maps uses their own algorithm for determining snowfall totals

[East Dubzz]

Wonder is the NAM is just doing its normal weird stuff , because man that looks nothing like the other models.

[WBadgersW]

Wonder is the NAM is just doing its normal weird stuff , because man that looks nothing like the other models.

Probably, it is long range NAM. GFS looks healthy at hour 54

[Money]

GFS with 10-12 inches for N. IL about 6-8 for Geos area.

 

Overall,  it's wetter/stronger and a bit north than 12z GFS.

[Geos]

GFS strong... and with Lake enhanced snow too.

 

[Iowa2015]

18z gfs nice for all of iowa pretty constant

[WBadgersW]

Just another slight bump North on the GFS and I'm golden.

[Geos]

 

[Tony]

_{^All I can say is "WOW" to those numbers in the maps above that Geos posted. Models have been pretty consistent on the strenght of this storm. It has plenty of energy to work with coming off of the PAC NW.}

[NEJeremy]

winter storm watches have gone up now from southeast SD into Iowa for up to 7" of snow

[james1976]

My God I'm loving this.

[Maxim]

Snow will compact a bit, so I'd take a couple inches off those totals, and probably another couple inches given mixing potential in the beginning and possibly lower ratios than expected. Final call for ORD: 6.0"

[james1976]

My county is in a winter storm watch!
And a wind advisory for tomorrow for up to 50 mph gusts. Quite the active week!

[Grizzcoat]

The Grizz is back!!!  Love this time of year!! Ways to go ,, but DMX a little more interested compared to whoever worked this AM--

 

THE NEXT ITEM WILL BE THE IMPENDING WINTER STORM. SHORT WAVE IN
QUESTION IS STILL CURRENTLY INTO THE PACIFIC BUT WILL RAPIDLY COME
ONSHORE INTO THE PACIFIC NW THU NIGHT BEFORE REACHING THE MO
VALLEY FRI. DEEP FORCING ASSOCIATED WITH THIS SYSTEM WILL RAPIDLY
MATURE INTO IA DURING THE DAY WITH NOTED THERMODYNAMIC AND
KINEMATIC CONTRIBUTIONS. MID LEVEL QG FORCING IS QUITE STRONG AS
IS THE THETA-E ADVECTION. SLOPED FRONTOGENETIC FORCING IS ALSO
NOTED INTO THE DEEP OVERALL QG FORCING. SIMILAR LIFT IS ALSO SHOWN
IN THE 285-295K ISENTROPIC LAYER WHICH IS NEAR THE DENDRITIC
GROWTH ZONE /DGZ/. MOISTURE TRANSPORT AND INFLOW INTO THE PRECIP
ZONE IS FAIRLY HIGH...AND SUPPORTS HIGHER QPF AMOUNTS DEPICTED IN
THE OPERATIONAL MODELS. THE DGZ DEPTH IS NOT EXTREME BUT IS CLOSE
TO THE MAX OMEGA INTO THE FRONTOGENETIC ZONE WHICH INCREASES
CHANCES OF HIGHER SNOW FALL RATES...AS DOES REDUCED STATIC
STABILITY AND LOWERING THETA-E LAPSE RATES. THESE FEATURES /QPF
AND SNOW RATIOS/ COMBINED LOOK TO BE SUFFICIENT FOR MODERATE TO
HEAVY SNOW. THUS HAVE RAISED SNOWFALL AMOUNTS INTO THE FOUR TO
SEVEN INCH RANGE ALONG AND NEAR THE HIGHWAY 20 AND 30 CORRIDORS.
CONFIDENCE IS NOT HIGH HOWEVER AS LOW LEVELS ARE DRY INITIALLY AND
SOME QPF WILL BE USED TO SATURATE THE COLUMN AND DROP TEMPS TO THE
WET BULB...AND THIS DOES NOT EVEN TAKE INTO ACCOUNT MODEL NORTH TO
SOUTH DIFFERENCES WHICH ALTER RAIN/SNOW LINE PLACEMENT AND
PROGRESSION. MODELS HAVE BEEN FAIRLY CONSISTENT WITH HIGHER
AMOUNTS HOWEVER SO WITH THIS BEING THE FIRST ACCUMS OF THE
SEASON...AND POTENTIALLY SIGNIFICANT AT THAT...HAVE ISSUED A
TARGETED WATCH TO RAISE AWARENESS FOR A START. THIS COULD BE
TRANSITIONED TO A LARGER ADVISORY OR EVEN WARNING AS NECESSARY.
ANOTHER CONCERN WILL BE LOW CONFIDENCE IN SENSIBLE WEATHER
OUTCOMES WITH AFOREMENTIONED ACCUMS MAINLY BEING ON VEGETATION
AND REDUCED A PERCENTAGE ON PAVEMENT DUE TO MELTING.

[Geos]

Should be a nice tree plastering event. Definitely looking forward to taking picture Saturday morning.

[james1976]

http://www.wpc.ncep.noaa.gov/wwd/day3_composite.gif

[GDR]

Looks like south of i80 in Iowa should think about throwing in the towel since models will be adjusting and push north.

[WBadgersW]

Looks like south of i80 in Iowa should think about throwing in the towel since models will be adjusting and push north.

You say this why?

[Maxim]

Looks like south of i80 in Iowa should think about throwing in the towel since models will be adjusting and push north.

yeah it's gonna be 70 and sunny instead, throw in the towel.

[GDR]

[Iowa2015]

Temporary torch Bye late next week single dight teens next weekend

[Maxim]

Temporary torch Bye late next week single dight teens next weekend

Now why would anyone want that? What's so fun about that?

[Grizzcoat]

[Iowa2015]

Now why would anyone want that? What's so fun about that?

Personally i take this same storm following Friday you could easily double whatever falls this Friday

[james1976]

FileL.png

Damm that is nice!

[Andrew NE]

I have a feeling Omaha is going to be too far south for this one. Wish it could dig some more before it gets to Iowa.

[Tom]

Thanks for all the posts today.  Been following them on my phone while I was working outside the office today.  Anyhow, this is turning out to be quite the system to track.  Seems like this PAC energy is getting better sampling and the models are picking up on the wave getting its act together earlier each run (reminds me of the days leading up to the Super Bowl storm but not quite as intense).   

 

http://www.tropicaltidbits.com/analysis/models/gfs/2015111818/gfs_asnow_ncus_17.png

 

 

I'm baffled to see the 18z GFS spitting out 6-11" for IA/N IL/S MI!  If trends continue, I expect to see NE fill in with a wider band of accumulating snow.  The way this system is laying out is characteristic of how this Winter storm track may end up becoming with blocking in central Canada.  I could see plenty of these west/east systems down the road...and of course, many cutters/gulf systems.

 

If we end up getting 6"+ at ORD, this would be the most snow I'd have seen pre-Thanksgiving!  It may stick around through the following week if what I think is going to happen.  Def going to try to put up my Christmas lights by Friday night...not going to risk waiting around.  That tanking EPO next week is going to wreck havoc on the models and try to "push" like it has the past 2 years.  We should have an interesting battle for that system over the following days.

 

BTW, as for the ground temps go, looks like temps Thursday night might dip down into the upper 20's around here which should cool the ground a bit before the snow falls later on Friday.  Nonetheless, Let it Snow!

[centralweather44]

We dont seem to do very well in Lincoln and Omaha with the clippers. I expect to see a little bit of snow but 4" ground temps are still in the 40's around here. Most will melt after hitting the ground. It would be great to see a healthy snow before thanksgiving. But doesn't happen very often here in southeast Nebraska. We usually have to wait until December before that happens.

[Geos]

If it dips into the 20s tomorrow night and is cloudy on Friday, then ground temps should be cold enough. The storm on 12/1/06 came right after a big mild spell like this one. Didn't have trouble putting down 12.5" here.

[centralweather44]

True. We will just need a bit of heavy banding. I know a lot of things are still up in the air. Things have been settling south a little bit compared to what it was a few days ago. We are right on the edge of 1-2 inches right now. Would love to squeeze out 1 or 2 inches to get the plows on the ground. It will be interested to see what the models do tomorrow. Winds just picked up here in Lincoln about 30 minutes ago. Blowing around 20-30 mph, with gusts even higher.

[Grizzcoat]

NAM through 51 seems to be trending South.