Alert archive / Illinois / Severe Thunderstorm Warnings in 1994

Severe Thunderstorm Warning 41, NWS Chicago, IL

July 5, 1994Cook County, Illinois; Lake County, Indiana

NWS Chicago, IL issued this severe thunderstorm warning at Jul 5, 1994, 3:45 PM CDT for Cook County, Illinois; Lake County, Indiana. It was in force for 45 min.

The area

The counties it named.

The facts

Issued
Jul 5, 1994, 3:45 PM CDT (20:45 UTC)
Expired
Jul 5, 1994, 4:30 PM CDT
In force
45 min
Issued by
NWS Chicago, IL
Area
Whole counties

Counties Cook County, IL, Lake County, IN

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 8.8 hours before the alert went out and 315 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 12:00Z on 1994-07-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 70 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Green Bay/Straub, WI at 12:00Z on 1994-07-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -19 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
70 J/kg
Mixed-layer CIN
-344 J/kg
Mixed-layer LCL
910 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
-19 m²/s²
0-3 km storm-relative helicity
35 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, Jul 5, 2:00 PM CDT, 1 hour 45 minutes before
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>
Special weather statement, Jul 5, 2:15 PM CDT, 1 hour 30 minutes before
ILZ003-004-011-061949-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ROCKFORD IL
215 PM CDT TUE JUL 5 1994

THOSE THUNDERSTORMS COVERING A LARGE PART OF LEE COUNTY ILLINOIS WERE
DRIFTING SLOWLY TO THE NORTH INTO SOUTHERN OGLE COUNTY. OTHER STORMS
WERE STARTING TO DEVELOP OVER PARTS OF CARROLL AND DE KALB COUNTIES
AS WELL.

PRESENTLY...OUR MAIN CONCERN IS FLOODING OF LOW LYING AREAS AND
FREQUENT CLOUD TO GROUND LIGHTNING STRIKES. MOVEMENT OF THESE STORMS
MAY PRODUCE AN INCH OF RAIN IN AN HOURS TIME OR LESS. DO NOT ATTEMPT
TO DRIVE THROUGH STANDING WATER. THE BEST BET WOULD BE TO STAY INDOORS
AWAY FROM WINDOWS TILL THE STORMS PASS.

OTHER STORMS ARE EXPECTED TO DEVELOP OVER MUCH OF THE AREA AS THE
AFTERNOON PROGRESSES.

FIELDS
Special weather statement, Jul 5, 2:29 PM CDT, 1 hour 16 minutes before
ILZ005-006-012>014-019>023-032-033-039-INZ001-002-052230-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
230 PM CDT TUE JUL 5 1994

...A HEAT ADVISORY REMAINS IN EFFECT FOR THE CHICAGO METROPOLITAN AREA
INCLUDING LAKE COUNTY INDIANA THIS AFTERNOON AND EVENING...

HEAT INDICES ACROSS THE CHICAGOLAND AREA HAVE EXCEEDED 105 DEGREES AND
ARE EXPECTED TO REACH VALUES OF AROUND 110 DEGREES BY LATE THIS
AFTERNOON. THESE EXTREME HEAT INDEX VALUES ARE A RESULT OF TEMPERATURES
IN THE MID 90S AND AFTERNOON HUMIDITIES BETWEEN 50 AND 60 PERCENT.

SUNSTROKE...HEAT CRAMPS AND HEAT EXHAUSTION ARE LIKELY WITH PROLONGED
EXPOSURE AND/OR PHYSICAL ACTIVITY UNDER THESE CONDITIONS. PERSONS WHO
ARE OUTDOORS SHOULD TAKE APPROPRIATE PRECAUTIONS TO ALLEVIATE THESE
SYMPTOMS.

CONSIDINE
Special weather statement, Jul 5, 2:30 PM CDT, 1 hour 15 minutes before
ILZ005-006-012>014-019>023-032-033-039-INZ001-002-052230-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
230 PM CDT TUE JUL 5 1994

...A HEAT ADVISORY REMAINS IN EFFECT FOR THE CHICAGO METROPOLITAN AREA
INCLUDING LAKE COUNTY INDIANA THIS AFTERNOON AND EVENING...

HEAT INDICES ACROSS THE CHICAGOLAND AREA HAVE EXCEEDED 105 DEGREES AND
ARE EXPECTED TO REACH VALUES OF AROUND 110 DEGREES BY LATE THIS
AFTERNOON. THESE EXTREME HEAT INDEX VALUES ARE A RESULT OF TEMPERATURES
IN THE MID 90S AND AFTERNOON HUMIDITIES BETWEEN 50 AND 60 PERCENT.

SUNSTROKE...HEAT CRAMPS AND HEAT EXHAUSTION ARE LIKELY WITH PROLONGED
EXPOSURE AND/OR PHYSICAL ACTIVITY UNDER THESE CONDITIONS. PERSONS WHO
ARE OUTDOORS SHOULD TAKE APPROPRIATE PRECAUTIONS TO ALLEVIATE THESE
SYMPTOMS.

CONSIDINE
Special weather statement, Jul 5, 3:17 PM CDT, 28 minutes before
ILZ005-006-012>014-020>023-INZ001-052120-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
317 PM CDT TUE JUL 5 1994

...THUNDERSTORMS DEVELOP SOUTH OF CHICAGO...

THE HOT HUMID AIR HAS BOILED UP A NARROW BAND OF THUNDERSTORMS JUST
NORTH OF KANKAKEE EXTENDING TOWARD THE SOUTH SUBURBS OF CHICAGO.

AT 5 PM THE STRONGEST CELL IS ABOUT 10 MILES NORTH OF KANKAKEE. OTHER
THUNDERSTORMS EXTEND NORTH ALONG I57 TOWARD THE SOUTH SHORE OF LAKE
MICHIGAN AND WEST OF THE INIANA STATE LINE.

THESE THUNDERSTORMS ARE MOVING NORTHEAST ABOUT 25 MPH AND WILL LIKELY
DEVELOP INTO WESTERN LAKE COUNTY INDIANA BEFORE 4PM.  GUSTY
WINDS...VERY HEAVY RAIN SHOWERS AND SMALL HAIL CAN BE EXPECTED WITH THE
 STRONGER CELLS.

KML
Special weather statement, Jul 5, 3:18 PM CDT, 27 minutes before
ILZ005-006-012>014-020>023-INZ001-052120-

SPECIAL WEATHER STATEMENT..COR FOR TYPOS
NATIONAL WEATHER SERVICE CHICAGO IL
317 PM CDT TUE JUL 5 1994

...THUNDERSTORMS DEVELOP SOUTH OF CHICAGO...

THE HOT HUMID AIR HAS BOILED UP A NARROW BAND OF THUNDERSTORMS JUST
NORTH OF KANKAKEE EXTENDING TOWARD THE SOUTH SUBURBS OF CHICAGO.

AT 315 PM THE STRONGEST CELL IS ABOUT 10 MILES NORTH OF KANKAKEE. OTHER
THUNDERSTORMS EXTEND NORTH ALONG I57 TOWARD THE SOUTH SHORE OF LAKE
MICHIGAN AND WEST OF THE INDIANA STATE LINE.

THESE THUNDERSTORMS ARE MOVING NORTHEAST ABOUT 25 MPH AND WILL LIKELY
DEVELOP INTO WESTERN LAKE COUNTY INDIANA BEFORE 4PM.  GUSTY
WINDS...VERY HEAVY RAIN SHOWERS AND SMALL HAIL CAN .BE EXPECTED WITH THE
STRONGER CELLS.

KML

The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 5, 4:09 PM CDTSevere Thunderstorm WarningLOTKankakee38 min
Jul 5, 4:43 PM CDTTornado WarningLOTKankakee32 min
Jul 5, 5:04 PM CDTSevere Thunderstorm WarningLOTBenton41 min

Nearby

Severe Thunderstorm Warnings in Illinois, 1994Severe Thunderstorm Warnings in Indiana, 1994Every severe thunderstorm warning in 1994

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.