January 30-February 1 Winter Storm Part 2

[hawkeye_wx]

I've received about an inch since it began around 7pm.

[janetjanet998]

LOT up to 3.1

so 2 inches the past 3 hours

[Chicago Storm]

1 minute ago, janetjanet998 said:

I believe that is snow depth 

not sure what they started with 4-5ish ????

4" was the starting point today.

Which means there was a max depth of 4.4" prior to this event.

[janetjanet998]

AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL  
900 PM CST SAT JAN 30 2021  
   
UPDATE  
  
858 PM CST  
  
MUCH OF THE GOING FORECAST IS IN GOOD SHAPE. ROLLING ADJUSTMENTS  
WITH OBSERVATIONAL TRENDS THIS EVENING INCLUDE FOR OGLE, LEE,  
LASALLE, LIVINGSTON, AND SOUTHERN FORD COUNTIES, WHERE HAVE HELD   
ONTO MIXED PRECIPITATION LONGER AND DIMINISHED SNOW AMOUNTS.  
ELSEWHERE CONTINUED SNOW, AT TIMES HEAVY, ALONG WITH BLOWING SNOW  
REMAINS IN THE FORECAST. FORECAST AMOUNTS IN THESE AREA ARE   
GENERALLY THE SAME.  
  
SATELLITE AND RADAR IMAGERY DEPICT THE CENTER OF THE UPPER TO  
MID-LEVEL CIRCULATION OVER NORTHEAST MISSOURI/FAR SOUTHWEST  
ILLINOIS AND MOVING SLOWLY NEAR DUE EAST. A SOLID MOISTURE PUMP  
IS AHEAD OF THIS WITH PRECIPITABLE WATER AT 0.86 ON THE 00Z ILX  
SOUNDING, IN THE TOP 5TH PERCENTILE FOR TIME OF YEAR. ALSO WITH  
THE 35-45 KT LOW-LEVEL JET HAS BEEN A WARM NOSE, SAMPLED AT A  
SURPRISINGLY HIGH +4C AND +5C ON THE 00Z DVN AND ILX SOUNDINGS,  
RESPECTIVELY. THIS WARM NOSE HAS ONLY SLIGHTLY EASED THUS FAR  
ACROSS THE WESTERN AND SOUTHERN FORECAST AREA, WITH RADAR  
CORRELATION COEFFICIENT INDICATING THE MELTING HYDROMETEOR LAYER  
FROM OGLE/LEE COUNTIES SOUTHEAST TO LIVINGSTON/FORD COUNTIES, AND  
AT TIMES PROTRUDING NORTH OF THAT REFLECTING HOW STOUT THE LLJ IS  
TO AT TIMES OFFSET DYNAMIC COOLING. IT'S JUST TO THE EAST AND   
NORTHEAST OF THIS ZONE IN PARTS OF THE SOUTHERN CHICAGO SUBURBS,   
I-57 CORRIDOR, AND INTO NORTHWEST INDIANA WHERE SOME OF THE   
HEAVIEST SNOW HAS BEEN. AN EXAMPLE OF THAT GRADIENT IS REFLECTED   
IN THE FACT THAT RANTOUL (TIP) HAS BEEN REPORTING RAIN THE WHOLE   
EVENT AND THEN NORTHEAST OF THERE ONLY 30 MILES, MILFORD, IL HAS   
REPORTED FOUR INCHES OF SNOW AS OF 830 P.M.   
  
SO HAVE HELD ONTO A LONGER MIX AND DIMINISHED SNOW AMOUNTS SOME   
ALONG AND TO THE SOUTH OF THAT LINE. THE GREATEST DIMINISHING WAS  
OF A COUPLE INCHES AND THAT CAME IN PARTS OF WESTERN LEE AND   
WESTERN AND SOUTHERN LASALLE AND LIVINGSTON COUNTIES. WILL TWEAK   
THIS WORDING IN THE UPCOMING WINTER HEADING UPDATE, BUT NO   
CHANGES PLANNED TO TYPE OF HEADLINES AT THIS JUNCTURE, AS THE   
MESSAGE IS STILL CONVEYED WELL.  
   
IT CONTINUES TO POUR SNOW ACROSS MUCH OF THE CHICAGOLAND AREA AND  
INTO NORTHWEST INDIANA ON DEEP ISENTROPIC ASCENT AND TAPPING INTO  
SOME STEEPER LAPSE RATES ABOVE 550 MB. THESE BETTER LAPSE RATES,  
ALONG WITH JUST MORE ENHANCED LEFT EXIT REGION JET DYNAMICS, ARE  
INTO THE KANKAKEE RIVER VALLEY AREA AND NORTHWEST INDIANA. THIS IS  
WHERE SOME MORE FREQUENT 1/4 TO 1/2 SM VISIBILITIES HAVE BEEN  
OBSERVED AT AUTOMATED STATIONS OR REPORTED. TRAVEL IS HAZARDOUS  
ACROSS MUCH OF THE AREA TONIGHT AND THAT SHOULD CONTINUE, SO GOING  
MESSAGING CADENCE ON THAT WILL CONTINUE. STILL LOOKS LIKE  
DIMINISHING OF SNOW INTENSITY WILL HAPPEN THROUGH THE OVERNIGHT,  
WITH SOME POSSIBLE MIX TO DRIZZLE/FREEZING DRIZZLE. NO CHANGES  
MADE TO SUNDAY AT THIS TIME.  
  
MTF  
  

[ChiTownStorm11]

Absolute pound town. Shades of GHD I intensity with this one. Snow has begun to cover I-90/94 downtown.

 

 

[tuanis]

20 minutes ago, A-L-E-K said:

 

Finally looks like legit winter on the lakefront

[madwx]

Still coming down but can’t get a large flake size.  Wind is howling out there which will make measuring futile 

[Jim Martin]

 

[TheNiño]

30 minutes ago, A-L-E-K said:

Delivering either way

Same up here in the Kenosha/Racine area. Lake Michigan is my backyard. Getting some large drifts already. This is the end of my driveway right now and we’re just getting started. 
 

I am thoroughly enjoying myself. 

[Gino27]

Battled virga for about 45 mins but am snow now!

[StormfanaticInd]

Looks to be over for Indy. 

[MIstorm97]

35 minutes ago, A-L-E-K said:

 

Being taken to the cleaners. Jelly of this

[Jim Martin]

 

[madwx]

1.6 inches at the MSN airport as of 9 pm

[Baum]

interested to see ratios. Does not seem 7:1 or 9:1 ratio.

[Hoosier]

7 minutes ago, Baum said:

interested to see ratios. Does not seem 7:1 or 9:1 ratio.

I went out to get a head start on some shoveling and measured 2.5" about 40 minutes ago.  It is ripping so probably topping 3" now.  The snow is kind of a sugary consistency but with some density.  Could make a snowball in my hand but it's not that great for packing.  Not overly wet at all.  

[frostfern]

18 minutes ago, Gino27 said:

Battled virga for about 45 mins but am snow now!

Still dealing with "heavy virga" overhead here.  Getting some pixie flurries with composite 25 dbz overhead.

[rickymortyx]

22 minutes ago, StormfanaticInd said:

Looks to be over for Indy. 

rain?

[cyclone77]

Snow is quite light as radar returns have really weakened.  Looks like long-duration light snows from here on out.  

[Jim Martin]

 

[janetjanet998]

snow mixing in now here on the NW side of PIA

[janetjanet998]

CHICAGO-OHARE  HVY SNOW  30  27  88 E20G29    29.85F VSB 1/4 

[frostfern]

5 minutes ago, Hoosier said:

I went out to get a head start on some shoveling and measured 2.5" about 40 minutes ago.  It is ripping so probably topping 3" now.  The snow is kind of a sugary consistency but with some density.  Could make a snowball in my hand but it's not that great for packing.  Not overly wet at all.  

Something I've noticed is that the ratio can depend as much on wind and crystal structure as temperature.  Dendrite-dominate lake effect that falls straight down in light wind can be much higher ratio at 30 degrees than wind-blown plate-dominant synoptic snows at 27 degrees.  I have seen 14:1 ratio with massive aggregate flakes even with a temperature of 30, provided there isn't a lot of wind and the depth is only a few inches.  Of course, once you get a depth of more than 4 inches, even dendrite-dominant large-aggregate snowpack will compress quickly to a 10:1 ratio if the temperature is anywhere near freezing.  It's usually under 4 inch snowfalls that can have a lot of variability based on crystal structure and wind.  Once you get a lot of depth there's more compression due to weight and so the ratio's become more purely temperature dependent.

[Jackstraw]

Back to full +SN now.  Much bigger flakes now.  

[janetjanet998]

KORD 310351Z 10017G25KT 1/4SM R10L/5000V5500FT +SN FZFG VV006 M01/M03 A2985
     RMK AO2 SLP115 DRSN SNINCR 1/8 P0003 T10111028

KMDW 310353Z 10015G27KT 3/4SM R31C/4000V5000FT -SN BR VV006 M01/M03 A2986
     RMK AO2 PK WND 08027/0347 SLP122 SNINCR 1/6 DRSN P0002 T10111028

[frostfern]

Well, the snow finally started reaching the ground here.  Had a solid 2 hours of virga and flurries.

[Jackstraw]

Besides the fact me and the dogs are now in trouble think that little break cost me an inch or 2.   Heading back wsw now, 1/4 mile vis again.  Seriously half dollars

[Chicago Storm]

Just went out for a drive, and conditions were as expected.

Probably the best period of snow I've see since the Nov 25-26th 2018 winter storm, and before that back in 2015.

[sbnwx85]

Got an inch in the ground after about two hours of snow. If we can keep this pace up we should get to about 5 inches by 12z.

[Chicago Storm]

ORD is somewhere over 3" thus far.

Up over 3" here as well.