The weather we've worried about for a couple of days looks set to hit this afternoon:
Four days of computer forecasts of this storm, including multiple runs off 7 models, are putting the developing system on a more northerly track while generating water equivalent precipitation of around 30 mm. To convert that to snow, calculations have to be made of how snowflakes are likely to develop in the storm given a snow/water ratio predicted to be 15 to 1 Tuesday evening. [This means 450 mm of snow. —ed.]
As expected, Lake Michigan may contribute an additional 75 to 175 mm to the system in lakeside counties
The National Weather Service warns:
A BLIZZARD WARNING REMAINS IN EFFECT FROM 3 PM THIS AFTERNOON TO
3 PM CST WEDNESDAY.
* TIMING...ACCUMULATING SNOW WILL DEVELOP AROUND THE INTERSTATE 80
CORRIDOR DURING THE EARLY TO MID AFTERNOON...SPREADING NORTH TO
THE WISCONSIN STATE LINE BY MID TO LATE AFTERNOON. THE MOST
SIGNIFICANT SNOW MAY COME IN A COUPLE OF WAVES...WITH THE FIRST
WAVE LATE THIS AFTERNOON INTO EARLY THIS EVENING...FOLLOWED BY A
SECOND WAVE OF INTENSE SNOW LATER THIS EVENING INTO THE
OVERNIGHT. ACCUMULATING LAKE EFFECT SNOW SHOWERS WILL CONTINUE
OVER NORTHEAST ILLINOIS WEDNESDAY MORNING...SPREADING INTO
NORTHWEST INDIANA WEDNESDAY AFTERNOON.
* ACCUMULATIONS...SNOW WILL BE HEAVY AT TIMES WITH ACCUMULATION
RATES OF 1 TO 2 INCHES PER HOUR LIKELY. STORM TOTAL SNOWFALL OF
10 TO 18 INCHES IS LIKELY TOWARD ROCKFORD AND DIXON. THE
HEAVIEST SNOWFALL TOTALS ARE LIKELY DOWNWIND OF LAKE MICHIGAN IN
THE CHICAGO METROPOLITAN AREA INTO NORTHWEST INDIANA WHERE 12 TO
20 INCHES OF SNOW IS LIKELY...WITH ISOLATED AMOUNTS OF AROUND 2
* WINDS...NORTHEAST WINDS WILL INCREASE TO 20 TO 35 MPH BY LATE
THIS AFTERNOON. WIND GUSTS UP TO 40 MPH WILL BE POSSIBLE BY
EVENING WITH GUSTS OF 40 TO 50 MPH LIKELY TONIGHT. EVEN STRONGER
WINDS ARE LIKELY NEAR THE IMMEDIATE LAKESHORE WITH SUSTAINED
WINDS OF 30 TO 40 MPH WITH GUSTS BETWEEN 50 AND 60 MPH.
The Daily Parker will have updates and photos as conditions warrant.