Alert archive / Illinois / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 116, NWS Chicago, IL

August 16, 2012Livingston County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Aug 16, 2012, 11:33 AM CDT for Livingston County, Illinois. It was in force for 42 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 16, 2012, 11:33 AM CDT (16:33 UTC)
Expired: Aug 16, 2012, 12:15 PM CDT
In force: 42 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Hail: 0.5 in
Wind: 60.0 mph

County Livingston County, IL

The radar

The Chicago radar (KLOT), 89 km from the middle of the area, began a volume at 16:35 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 4.6 hours before the alert went out and 83 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 817 J/kg
Mixed-layer CIN: -262 J/kg
Mixed-layer LCL: 1559 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 36 m²/s²
0-3 km storm-relative helicity: 69 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.0

Open this sounding in Storm Lab

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.

NWS Chicago, IL wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 16, 11:33 AM CDT, 0 minutes earlier.

Area forecast discussion, Aug 16, 11:33 AM CDT, 0 minutes before

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Hazardous weather outlook, Aug 16, 10:45 AM CDT, 48 minutes before

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1045 AM CDT THU AUG 16 2012

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
171545-
WINNEBAGO-BOONE-MCHENRY-LAKE ILLINOIS-OGLE-LEE-DE KALB-KANE-
DUPAGE-COOK-LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-
IROQUOIS-FORD-LAKE INDIANA-PORTER-NEWTON-JASPER-BENTON-
1045 AM CDT THU AUG 16 2012 /1145 AM EDT THU AUG 16 2012/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL ILLINOIS...
NORTHEAST ILLINOIS AND NORTHWEST INDIANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

  WEATHER HAZARDS EXPECTED:

  NUMEROUS THUNDERSTORMS...SOME MAY PRODUCE:
    VERY HEAVY RAINFALL AND MINOR FLOODING.
    DAMAGING WINDS IN EXCESS OF 60 MPH.
    HAIL TO THE SIZE OF HALF DOLLARS.
    FREQUENT CLOUD TO GROUND LIGHTNING.

  AREAS AFFECTED AND TIMING:

 SCATTERED TO NUMEROUS THUNDERSTORMS WILL CONTINUE TO REDEVELOP
 ACROSS AREAS SOUTH OF INTERSTATE 80 THROUGH EARLY TO MID
 AFTERNOON. THIS AREA IS UNDER A RISK FOR SEVERE WEATHER...WITH
 CHANCES BEING BETTER PRIOR TO 4 PM. SCATTERED SUB-SEVERE
 THUNDERSTORMS ARE POSSIBLE FOR PARTS OF THE REGION NORTH OF
 INTERSTATE 80 THROUGH EARLY AFTERNOON.

  DISCUSSION:

 AS A COLD FRONT MOVES EAST THROUGH THE AREA THIS
 AFTERNOON...THUNDERSTORM REDEVELOPMENT WILL CONTINUE WITHIN A
 MOIST AND UNSTABLE AIR MASS OVER AREAS MAINLY SOUTH OF INTERSTATE
 80. INCREASING WINDS ALOFT WILL ALSO SUPPORT ORGANIZED
 STORMS...CAPABLE OF POTENTIAL SEVERE WEATHER. THESE STORMS WILL
 EVENTUALLY PROGRESS SOUTH AND EAST OF THE AREA...LIKELY BY LATE
 AFTERNOON OR EARLY EVENING.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

THERE IS AN INCREASED RISK FOR RIP CURRENTS EARLY FRIDAY ALONG
THE LAKE MICHIGAN SHORES OF NORTHWEST INDIANA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NECESSARY IN AREAS SOUTH OF INTERSTATE
80 THROUGH THIS AFTERNOON.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

LMZ740>745-171545-
WINTHROP HARBOR TO WILMETTE HARBOR-
WILMETTE HARBOR TO NORTHERLY ISLAND-
NORTHERLY ISLAND TO CALUMET HARBOR-CALUMET HARBOR TO GARY-
GARY TO BURNS HARBOR-BURNS HARBOR TO MICHIGAN CITY-
1045 AM CDT THU AUG 16 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE ILLINOIS NEARSHORE
WATERS OF LAKE MICHIGAN AND THE INDIANA NEARSHORE WATERS OF LAKE
MICHIGAN.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

THERE IS A CHANCE OF THUNDERSTORMS THROUGH MID AFTERNOON...MAINLY
ALONG THE INDIANA NEAR SHORES...WITH SOME ISOLATED STORMS
POTENTIALLY PRODUCING WINDS IN EXCESS OF 35 KNOTS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-171545-
LAKE MICHIGAN FROM MICHIGAN CITY IN TO ST. JOSEPH MI 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM SEUL CHOIX POINT TO ROCK ISLAND PASSAGE 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN SOUTH OF A LINE FROM SEUL CHOIX POINT TO THE
MACKINAC BRIDGE AND NORTH OF A LINE FROM CHARLEVOIX MI TO SOUTH
FOX ISLAND 5 NM OFFSHORE-
LAKE MICHIGAN FROM CHARLEVOIX TO POINT BETSIE MI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM POINT BETSIE TO MANISTEE MI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM ROCK ISLAND PASSAGE TO STURGEON BAY WI-
LAKE MICHIGAN FROM STURGEON BAY TO TWO RIVERS WI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM TWO RIVERS TO SHEBOYGAN WI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM SHEBOYGAN TO PORT WASHINGTON WI 5 NM OFFSHORE
TO MID LAKE-
LAKE MICHIGAN FROM PORT WASHINGTON TO NORTH POINT LIGHT WI 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM NORTH POINT LIGHT TO WIND POINT WI 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM WIND POINT WI TO WINTHROP HARBOR IL 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM WINTHROP HARBOR TO WILMETTE HARBOR IL 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM WILMETTE HARBOR IL TO MICHIGAN CITY IN 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM PENTWATER TO MANISTEE MI 5 NM OFFSHORE TO MID
LAKE-
LAKE MICHIGAN FROM WHITEHALL TO PENTWATER MI 5 NM OFFSHORE TO MID
LAKE-
LAKE MICHIGAN FROM GRAND HAVEN TO WHITEHALL MI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM HOLLAND TO GRAND HAVEN MI 5 NM OFFSHORE TO MID
LAKE-
LAKE MICHIGAN FROM SOUTH HAVEN TO HOLLAND MI 5 NM OFFSHORE TO MID
LAKE-
LAKE MICHIGAN FROM ST. JOSEPH TO SOUTH HAVEN MI 5 NM OFFSHORE TO
MID LAKE-
1045 AM CDT THU AUG 16 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE OPEN WATERS OF LAKE
MICHIGAN.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

SCATTERED THUNDERSTORMS ALONG AND AHEAD OF A COLD FRONT WILL MOVE
OVER THE LAKE THROUGH EARLY THIS AFTERNOON...WITH SOME ISOLATED
STORMS POTENTIALLY PRODUCING WINDS IN EXCESS OF 35 KNOTS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

THERE IS A SLIGHT CHANCE OF THUNDERSTORMS OVER NORTHERN LAKE
MICHIGAN WEDNESDAY.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

MTF

In the hours before

Special weather statement, Aug 16, 6:26 AM CDT, 5 hours 7 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
626 AM CDT THU AUG 16 2012

ILZ003-004-008-010-011-019-161215-
BOONE IL-DE KALB IL-LA SALLE IL-LEE IL-OGLE IL-WINNEBAGO IL-
626 AM CDT THU AUG 16 2012

...SPECIAL WEATHER STATEMENT...

AT 621 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
THUNDERSTORMS...SOME STRONG...ALONG A LINE EXTENDING FROM 30 MILES
WEST OF ROCKFORD TO 40 MILES EAST OF PERU...MOVING EAST AT 55 MPH.

WINDS GREATER THAN 40 MPH...FREQUENT CLOUD TO GROUND LIGHTNING...
AND BRIEF HEAVY DOWNPOURS...ARE POSSIBLE WITH THESE STORMS AS THEY
ARRIVE THROUGH 730 AM.

CITIES AND TOWNS AFFECTED...
  FORRESTON...          POLO...               DIXON...
  MOUNT MORRIS...       LAKE SUMMERSET...     WALTON...
  PECATONICA...         DURAND...             OREGON...
  ROCKFORD...           PERU...               MENDOTA...

OTHER LOCATIONS AFFECTED...
BOONE COUNTY FAIRGROUNDS...CASTLE ROCK STATE PARK...LEE COUNTY
FAIRGROUNDS...LOWDEN STATE PARK...NORTHERN ILLINOIS UNIVERSITY...OGLE
COUNTY FAIRGROUNDS...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

GUSTY WINDS MAY CAUSE SMALL OBJECTS SUCH AS TRASH BINS TO BLOW
AROUND. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS TREES. HEAVY
RAINFALL COULD LEAD TO STANDING WATER ON ROADWAYS AND POOR
VISIBILITY. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THESE STORMS
HAVE PASSED.

&&

LAT...LON 4249 8871 4137 8874 4137 8917 4158 8918
      4159 8964 4192 8963 4193 8969 4220 8970
      4221 8940 4250 8940
TIME...MOT...LOC 1121Z 272DEG 47KT 4232 8978 4140 8985

Special weather statement, Aug 16, 7:08 AM CDT, 4 hours 25 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
708 AM CDT THU AUG 16 2012

ILZ019-161300-
LA SALLE IL-
708 AM CDT THU AUG 16 2012

...SPECIAL WEATHER STATEMENT...

AT 708 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 17 MILES NORTHWEST
OF PERU TO 12 MILES WEST OF PERU...MOVING EAST AT 40 MPH. THIS STORM
HAS SHOWN A GRADUAL WEAKENING TREND SINCE 655 AM.

UP TO PENNY SIZE HAIL...WINDS TO 50 MPH...FREQUENT CLOUD TO GROUND
LIGHTNING...BRIEF HEAVY DOWNPOURS...ARE POSSIBLE WITH THESE STORMS.

CITIES AND TOWNS AFFECTED...
  PERU...               TONICA...             OGLESBY...
  LA SALLE...           UTICA...              NAPLATE...
  OTTAWA...             GRAND RIDGE...        INTERSTATE 39...
  INTERSTATE 80...

OTHER LOCATIONS AFFECTED...
BUFFALO ROCK STATE PARK...ILLINOIS VALLEY COMMUNITY COLLEGE...
MATTHIESSEN STATE PARK...STARVED ROCK STATE PARK...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

GUSTY WINDS MAY CAUSE SMALL BRANCHES TO BE BLOWN DOWN...AND LOOSE
OBJECTS TO BLOW AROUND. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS
TREES. HEAVY RAINFALL COULD LEAD TO STANDING WATER ON ROADWAYS AND
POOR VISIBILITY. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THESE
STORMS HAVE PASSED.

&&

LAT...LON 4153 8884 4113 8882 4123 8917 4153 8917
TIME...MOT...LOC 1208Z 278DEG 35KT 4153 8928 4130 8930

Local storm report, Aug 16, 9:01 AM CDT, 2 hours 32 minutes before

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Special weather statement, Aug 16, 9:52 AM CDT, 1 hour 41 minutes before

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Special weather statement, Aug 16, 10:04 AM CDT, 1 hour 29 minutes before

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Special weather statement, Aug 16, 11:16 AM CDT, 17 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1116 AM CDT THU AUG 16 2012

ILZ032-039-161700-
FORD IL-LIVINGSTON IL-
1116 AM CDT THU AUG 16 2012

...SPECIAL WEATHER STATEMENT...

AT 1115 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 14 MILES NORTHWEST OF GIBSON CITY...MOVING EAST
AT 35 MPH.

UP TO PENNY SIZE HAIL...WINDS GREATER THAN 40 MPH...FREQUENT CLOUD TO
GROUND LIGHTNING...AND BRIEF HEAVY DOWNPOURS...ARE POSSIBLE WITH THIS
STORM.

CITIES AND TOWNS AFFECTED...
  STRAWN...
  SIBLEY...
  MELVIN...
  ILLINOIS HIGHWAY 47...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

GUSTY WINDS MAY CAUSE SMALL OBJECTS SUCH AS TRASH BINS TO BLOW
AROUND. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS TREES. HEAVY
RAINFALL COULD LEAD TO STANDING WATER ON ROADWAYS AND POOR
VISIBILITY. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THIS STORM HAS
PASSED.

&&

LAT...LON 4048 8847 4061 8846 4062 8857 4062 8858
      4066 8858 4067 8859 4071 8859 4073 8813
      4042 8812
TIME...MOT...LOC 1615Z 275DEG 32KT 4062 8853

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 16, 6:26 AM CDT	Special Weather Statement	LOT	Boone, DeKalb, Lee, Ogle, Winnebago	49 min
Aug 16, 7:08 AM CDT	Special Weather Statement	LOT	LaSalle	52 min
Aug 16, 11:16 AM CDT	Special Weather Statement	LOT	Ford	44 min
Aug 16, 12:00 PM CDT	Severe Thunderstorm Warning	LOT	Ford, Livingston	30 min
Aug 16, 12:27 PM CDT	Special Weather Statement	LOT	Ford, Iroquois	33 min
Aug 16, 12:43 PM CDT	Severe Thunderstorm Warning	LOT	Ford, Iroquois	47 min
Aug 16, 2:21 PM CDT	Special Weather Statement	LOT	Ford	39 min
Aug 16, 9:52 AM CDT	Special Weather Statement	LOT	Jasper	23 min
Aug 16, 10:04 AM CDT	Special Weather Statement	LOT	Benton	26 min
Aug 16, 3:48 PM CDT	Rip Current Statement	LOT	Lake, Porter	27 hr

Nearby

Severe Thunderstorm Warnings in Illinois, 2012 Every severe thunderstorm warning in 2012

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; radar from the NEXRAD Level II archive.