National Weather Service United States Department of Commerce

 
 
Overview
  • Wind gusts of 45 to 60 mph were observed across northern Illinois and northwest Indiana.
  • The peak wind gusts at both Chicago O'Hare and Rockford were 54 mphThe strongest wind gust observed over land was 60 mph at Pontiac and over water 61 mph at the Chicago Harrison-Dever Crib.
  • Numerous snow showers, at times mixed with graupel, moved over northern Illinois and northwest Indiana through the day.  These were what we call convective showers, in that they were formed by simliar processes to convection...or thunderstorms.  Thus they produced brief but heavy snowfall rates.  Combined with the winds this brought near white-out conditions.    . 


 

Peak Wind Gusts
 
Peak Winds    
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
637 PM CDT SAT APR 2 2016

...HIGHEST WIND GUSTS ON SATURDAY APRIL 2...

LAND LOCATION                SPEED     TIME/DATE
----------------------------------------------------
PAXTON                       64 MPH    0110 PM 04/02
PONTIAC AIRPORT              60 MPH    1135 AM 04/02
2 SSE STEWARD                59 MPH    1225 PM 04/02
PERU AIRPORT                 59 MPH    1135 AM 04/02
SUGAR GROVE - AURORA AIRPORT 56 MPH    1209 PM 04/02
MORRIS AIRPORT               56 MPH    0135 PM 04/02
CHICAGO MIDWAY               56 MPH    1141 AM 04/02
ROCHELLE AIRPORT             55 MPH    0135 PM 04/02
ROMEOVILLE - LEWIS AIRPORT   54 MPH    0235 PM 04/02
CHICAGO O`HARE               54 MPH    1225 PM 04/02
ROCKFORD AIRPORT             54 MPH    1156 AM 04/02
DE KALB AIRPORT              52 MPH    1255 PM 04/02
VALPARAISO AIRPORT           52 MPH    0129 PM 04/02
DUPAGE AIRPORT               51 MPH    1205 PM 04/02
WHEELING - CHI EXEC AIRPORT  51 MPH    0107 PM 04/02
RENSSELAER AIRPORT           51 MPH    1235 PM 04/02
KANKAKEE AIRPORT             49 MPH    1215 PM 04/02
LANSING AIRPORT              48 MPH    1215 PM 04/02
WAUKEGAN AIRPORT             46 MPH    0401 PM 04/02
JOLIET AIRPORT               44 MPH    0135 PM 04/02


MARINE LOCATION              SPEED     TIME/DATE
----------------------------------------------------
CHICAGO HARRISON-DEVER CRIB  61 MPH    0131 PM 04/02
BURNS HARBOR                 60 MPH    1230 PM 04/02
WAUKEGAN HARBOR              49 MPH    1140 AM 04/02


OBSERVATIONS ARE COLLECTED FROM A VARIETY OF SOURCES WITH VARYING
EQUIPMENT AND EXPOSURE. NOT ALL DATA LISTED ARE CONSIDERED OFFICIAL.

$$

MTF/RC
 
 
 
 
Reports
 

 

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
544 PM CDT SAT APR 02 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0530 PM     SNOW             3 SW MIDWAY AIRPORT     41.75N 87.79W
04/02/2016  M0.5 INCH        COOK               IL   CO-OP OBSERVER

            LIQUID EQUIVALENT 0.06 INCHES.

0318 PM     HEAVY SNOW       YORKVILLE               41.64N 88.45W
04/02/2016  U0.0 INCH        KENDALL            IL   CO-OP OBSERVER

            HEAVY SNOW AND STRONG WINDS CAUSING VISIBILITY BELOW 200
            FEET.

0300 PM     HEAVY SNOW       ROMEOVILLE              41.65N 88.09W
04/02/2016  U0.0 INCH        WILL               IL   OFFICIAL NWS OBS

            HEAVY SNOW AND STRONG WINDS CAUSING VISIBILITY BRIEFLY
            UNDER 1/8 MILE.

0252 PM     HEAVY SNOW       DUPAGE AIRPORT          41.92N 88.25W
04/02/2016  U0.0 INCH        DUPAGE             IL   ASOS

            OBSERVATION WITH 1/4 MILE VISIBILITY IN HEAVY
            THUNDERSNOW.

0220 PM     NON-TSTM WND DMG 4 NNE LITTLE ROCK       41.76N 88.55W
04/02/2016                   KANE               IL   TRAINED SPOTTER

            TWO SMALL SOFTWOOD TREES UPROOTED IN BIG ROCK.

0215 PM     SNOW             2 NE ELGIN              42.06N 88.26W
04/02/2016  M0.4 INCH        COOK               IL   COCORAHS

            HIGHEST WIND GUST ON THE DAY ESTIMATED AT 50 MPH AT 11AM.


0210 PM     NON-TSTM WND DMG 3 N ROCKFORD            42.31N 89.06W
04/02/2016                   WINNEBAGO          IL   TRAINED SPOTTER

            LARGE TREE BRANCH SNAPPED OFF FROM A MATURE MAPLE TREE.

0151 PM     HEAVY SNOW       OHARE AIRPORT           41.98N 87.90W
04/02/2016  U0.0 INCH        COOK               IL   ASOS

            1/8 MILE VISIBILITY IN HEAVY SNOW WITH 44 MPH WIND GUST
            AT OBSERVATION TIME.

0135 PM     NON-TSTM WND GST 3 SW MIDWAY AIRPORT     41.75N 87.79W
04/02/2016  M59.00 MPH       COOK               IL   CO-OP OBSERVER

            PEAK WIND GUST FOR THE DAY. ALSO 0.2 INCHES OF SNOW
            MEASURED ON THE DAY.

0131 PM     NON-TSTM WND GST 4 NE CHICAGO            41.92N 87.57W
04/02/2016  M61.00 MPH       LMZ741             IL   C-MAN STATION

            52.7 KT PEAK WIND GUST ON THE DAY AT THE CHICAGO
            HARRISON-DEVER CRIB.

1250 PM     HEAVY SNOW       ELK GROVE VILLAGE       42.01N 87.99W
04/02/2016  M0.4 INCH        COOK               IL   COCORAHS

            HIGH WINDS WITH SNOW GRAINS AND WHITE OUT CONDITIONS
            WITHIN THE HOUR. VISIBILITY TO 1/8 MILE OR LESS.

1245 PM     HEAVY SNOW       3 NNW LINCOLN PARK      41.97N 87.66W
04/02/2016  U0.0 INCH        COOK               IL   PUBLIC

            HEAVY THUNDERSNOW AT LAWRENCE AVE AND BROADWAY STREET IN
            UPTOWN SECTION OF CHICAGO.

1245 PM     HEAVY SNOW       2 E SCHAUMBURG          42.03N 88.04W
04/02/2016  M0.5 INCH        COOK               IL   COCORAHS

            1/2 INCH OF SNOW IN 10 MINUTES UP TO OBSERVATION TIME.
            VISIBILITY LESS THAN 1/16 MILE.

1241 PM     NON-TSTM WND DMG ST. ANNE                41.02N 87.72W
04/02/2016                   KANKAKEE           IL   PUBLIC

            SMALL TREE BLOWN DOWN. RELAYED VIA FACEBOOK.

1230 PM     NON-TSTM WND DMG ELGIN                   42.04N 88.29W
04/02/2016                   KANE               IL   PUBLIC

            SOFTWOOD TREE BLOWN OVER JUST WEST OF IL 19 AND ROHRSSEN
            ROAD. TIME OF OCCURRENCE UNKNOWN. RELAYED VIA TWITTER.

1230 PM     NON-TSTM WND DMG BATAVIA                 41.85N 88.30W
04/02/2016                   KANE               IL   TRAINED SPOTTER

            POWERPOLES DOWN ALONG WESTERN AVENUE.

1220 PM     NON-TSTM WND DMG LELAND                  41.61N 88.80W
04/02/2016                   LA SALLE           IL   TRAINED SPOTTER

            MEDIUM SIZED TREE BRANCHES BLOWN DOWN. POWER OUTAGES IN
            THE AREA.

1215 PM     NON-TSTM WND DMG NORTH AURORA            41.80N 88.33W
04/02/2016                   KANE               IL   NWS EMPLOYEE

            SECTION OF SHINGLES BLOWN FROM ROOF.

1203 PM     HEAVY SNOW       CRYSTAL LAKE            42.23N 88.33W
04/02/2016  E0.0 INCH        MCHENRY            IL   TRAINED SPOTTER

            THUNDERSNOW WITH NEAR ZERO VISIBILITY. SEVERAL OTHER
            REPORTS OF NEAR ZERO VISIBILITY IN PARTS OF MCHENRY AND
            LAKE COUNTIES IN ILLINOIS BETWEEN ABOUT 1030 AM AND NOON.


1141 AM     NON-TSTM WND GST MIDWAY AIRPORT          41.78N 87.75W
04/02/2016  M56.00 MPH       COOK               IL   ASOS

1135 AM     NON-TSTM WND GST PONTIAC                 40.88N 88.64W
04/02/2016  M60.00 MPH       LIVINGSTON         IL   AWOS

1135 AM     NON-TSTM WND GST PERU                    41.34N 89.13W
04/02/2016  M59.00 MPH       LA SALLE           IL   AWOS

1133 AM     NON-TSTM WND DMG CHANNAHON               41.43N 88.22W
04/02/2016                   WILL               IL   PUBLIC

            SHINGLES BLOWN OFF OF SOME HOUSES. RELAYED VIA FACEBOOK.


1130 AM     NON-TSTM WND GST LIBERTYVILLE            42.28N 87.97W
04/02/2016  M59.00 MPH       LAKE               IL   EMERGENCY MNGR

            MEASURED AT LAKE COUNTY EOC.

1120 AM     HAIL             1 SSW DE MOTTE          41.19N 87.21W
04/02/2016  M0.25 INCH       JASPER             IN   COCORAHS

            PEA SIZED GRAUPEL.

1100 AM     NON-TSTM WND DMG PERU                    41.34N 89.13W
04/02/2016                   LA SALLE           IL   PUBLIC

            SOFTWOOD TREE UPROOTED.

0800 AM     SNOW             1 W BEACH PARK          42.42N 87.88W
04/02/2016  M0.5 INCH        LAKE               IL   COCORAHS


&&

$$

RC

 

 
 
 
 
Meteorology
 

 

Pressure Loop
Mean sea-level pressure (left) and 3hr mean sea-level pressure change (right) looped hourly from 2 a.m. through 7 p.m. on April 2nd.  The low pressure magnitude of 997 mb over Milwaukee during the morning is anomalously low especially for a springtime "Clipper" system, and such deep lows have an inherent stronger wind field due to the pressure gradient force.  In addition, the rapid speed of this low (which is common for "Clipper" systems) induced a high rate of change in pressure as shown by the right loop.  This strengthened the issalobaric component to the wind.  This is strongest in the zone between the maximum pressure falls and rises, which passes directly over northern Illinois and northwest Indiana.

 

Water Vapor Loop
GOES Water Vapor imagery looped with cloud-to-ground lightning shown from 2 a.m. through 7 p.m. on Saturday April 2nd.

 


 

Video & Photos

 

 
Photo
A graphic showing the rapid difference at the same locations over a small amount of time.  This is common with snow squalls, as the intensity of the snow and the strong winds helping to suspend some of the falling snow together sharply reduce the visibility.
 
 
Photo
From Wauconda, IL courtesy of Dirk Leahy.  This shows a strong precipitation shaft of snow, possibly mixed with graupel.
 
 
Photo
From Rockbridge, IL, courtesy of Kirby Brannan.
 

Photo

Photo
From near Devon and Harlem in Chicago, courtesy of Diane Krzywonos. From Lake Villa courtesy of Cathy Nestor.