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Fast Facts

  • During the late afternoon and early evening, multiple storms produced large hail and very heavy rainfall along the I-80 corridor, including across the far southern and southwestern Chicago metro area.  For a listing of rainfall totals, visit here.
  • The largest hail reported was over 4" in diameter, measured at 4.75", two miles north-northwest of Minooka around 7:20 pm.   There were many reports of 2.5" diameter hail and larger across Minooka from Emergency Management, law enforcement, and the public.  There were multiple reports of vehicle damage from this area.
  • The 4.75" diameter hail observed two miles north-northwest of Minooka was the largest documented hail stone in Illinois since at least 1961, and according to the Illinois State Climatologist, may be the largest documented hail stone able to be verified on record in the state. More here.  

  • A Severe Thunderstorm Warning was in effect for that area, including Minooka, issued at 7:05 pm.

 

Reports

 

Preliminary Storm Reports 10June2015

 


Photos and Video

 

Minooka IL Softball Size Hail 10June2015

Large Hail Minooka IL 10June2015
Photo of Hail Larger than Softball Size from Near Minooka IL.  This is the largest documnted hail in Illinois since at least 1961. Minooka IL

 

Large Hail between Morris and Minooka
Large Hail between Morris and Minooka IL

 

Video of Hail in Arbor Lakes Subdivision in Minooka Shared by Cassie Settelmyer with NWS Chicago on Facebook

 


Huge Hail in Perspective

Hail in Minooka IL on June 10, 2015 2nd Largest Hail in IL on record

PUBLIC INFORMATION STATEMENT...UPDATED
NATIONAL WEATHER SERVICE CHICAGO IL
942 PM CDT THU JUN 11 2015

...GIANT HAIL RECORDED IN MINOOKA ON JUNE 10TH WAS THE SECOND
LARGEST OBSERVED HAIL ON RECORD IN THE STATE OF ILLINOIS...

SEVERAL SEVERE STORMS DEVELOPED ACROSS NORTHERN ILLINOIS ON
WEDNESDAY JUNE 10TH. ONE OF THESE PASSED OVER MINOOKA ILLINOIS IN
GRUNDY COUNTY BETWEEN 715 AND 725 PM AND PRODUCED ISOLATED GIANT
HAIL OF UP TO OVER FOUR INCHES IN DIAMETER. THERE WAS A REPORT OF
HAIL TO 4.75 INCHES IN DIAMETER FROM THE PUBLIC THAT WAS VERIFIED
PHOTOGRAPHICALLY. SOME OF THIS HAIL CAUSED SEVERE DAMAGE TO
VEHICLE WINDSHIELDS.

LOOKING AT LARGE HAIL DATA THROUGH THE STORM DATA EVENTS DATABASE
FROM THE NOAA NATIONAL CLIMATIC DATA CENTER /NCDC/...INFORMATION
WAS RETRIEVED THAT MAY HELP TO PUT HAIL THIS SIZE INTO
PERSPECTIVE. RECORDS ON HAIL DATA DATE BACK TO 1950 BUT BECAME
MORE DETAILED AND ROBUST BEGINNING IN THE MID TO LATE 1990S.
ACCORDING TO THE DATABASE:

- THIS WAS THE SECOND LARGEST OBSERVED HAIL ON RECORD IN THE STATE
OF ILLINOIS. THE LARGEST OBSERVED HAIL ON RECORD IN ILLINOIS WAS
ON APRIL 23 1961...WHEN SIX INCH DIAMETER HAIL WAS REPORTED IN
KANKAKEE COUNTY.

- THERE HAVE BEEN 9 INSTANCES OF 4.5 INCH DIAMETER HAIL OBSERVED
IN ILLINOIS...WHICH PREVIOUSLY TIED FOR THE SECOND LARGEST
OBSERVED HAIL ON RECORD IN THE STATE. THE MOST RECENT OCCURRENCE
WAS ON APRIL 28 2012 IN OKAWVILLE IN WASHINGTON COUNTY.

- OVERALL...SINCE 1950...THERE HAVE BEEN ONLY 24 OCCURRENCES OF 4
INCH DIAMETER OR LARGER HAIL IN ILLINOIS AND ONLY 17 OCCURRENCES OF
4 INCH DIAMETER OR LARGER HAIL IN THE STATE OF INDIANA.

- INCLUDING THE 1961 INSTANCE NOTED ABOVE...HERE ARE THE ONLY
INSTANCES OF HAIL OF 4 INCHES OR LARGER IN THE NWS CHICAGO COUNTY
WARNING AREA:

KANKAKEE COUNTY:      APRIL 23 1961:      6 INCH DIAMETER
MINOOKA (GRUNDY):      JUNE 10 2015:   4.75 INCH DIAMETER
BOSWELL (BENTON):      JUNE 14 2010:   4.25 INCH DIAMETER
KANKAKEE COUNTY:        JUNE 8 1981:      4 INCH DIAMETER
COUNTYWIDE (BENTON): AUGUST 18 2001:      4 INCH DIAMETER
DIXON (LEE COUNTY):    JULY 13 2004:      4 INCH DIAMETER

- SINCE 2005...HAIL OF THIS LARGE IN DIAMETER IS REPORTED ABOUT
35-40 TIMES A YEAR IN THE UNITED STATES. HOWEVER...ALMOST ALL OF
THESE REPORTS ARE FROM THE PLAINS STATES.

$$

RC/MTF

Hail Safety Reminder

The National Weather Service received many photos of the large hail on Wednesday and these visual reports assisted us with warning messages to better stress the dangerous nature of the storms, as well as verification efforts after. Thank you!

It is important to remember that severe storms are dangerous, and hail to the size of Wednesday's can injure and be deadly. While photos may be beneficial to us, ensure safety first and foremost. It is absolutely fine if the hail pictures have to wait to after the storm has ended, because after all, hail of this size will take quite a while to melt!

A reminder that the best place to be in severe storms is inside and central in a sturdy structure, away from windows, and putting as many walls between you and the severe storm as possible.

 


Meteorology & Radar

 

NWS Chicago Doppler Radar 0.5° Base Reflectivity Loop:  3:30 pm - 8:30 pm
Radar Loop

 

3D Radar Perspective

 

 

 

  • Many areas across Northern IL and Northwest IN experienced their first 90° day of the summer. Coupled with the very warm conditions were high amounts of low level moisture. Dew points had risen into the upper 60s to lower 70s. Here is a look at the deep moisture, or Precipitable Water (PWAT), in an analysis from the Storm Prediction Center at 6PM CDT across the region. Note the axis of PWAT values in excess of 1.5" across a portion of Northern IL.
SPC Mesoanalysis 6PM CDT PWAT 10June2015
SPC Mesoanalysis: Precipitable Water (in) at 6PM CDT 10June2015

 

 

  • Typically when large hail occurs, we experience a highly sheared environment. But that is not always the case, and the setup that produced the softball size hail in Minooka IL was a good example of this. Severe thunderstorms can and frequently do create their own environments. The setup in this case was extremely strong updrafts that continued to hold the hail stones aloft enabling them to grow. Below is an image depicting the Effective Shear across Northern IL and Northwest IN.

 

SPC/Mesoanalysis Effective Shear 6PM CDT 10June2015
SPC Mesoanalysis: Effective Shear at 6PM CDT 10June2015

 

 

  • Along with the very warm and moist conditions, the atmosphere had equally become very unstable. One frequently used variable that is analyzed in the convective season is Mixed Layer Convective Available Potential Energy (MLCAPE). The image below from the SPC Mesoanalysis page indicated that the atmosphere was extremely unstable, with MLCAPE values in excess of 3000J/Kg across a portion of North Central IL and Northwest IN.

 

SPC/Mesoanalysis MLCAPE 6PM CDT 10June2015
SPC Mesoanalysis: MLCAPE at 6PM CDT 10June2015

 

NWS Doppler Radar Hail Detection 10June2015