Alert archive / Illinois / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 3, NWS Chicago, IL

April 9, 2013Boone County, McHenry County, Winnebago County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Apr 9, 2013, 9:26 AM CDT for Boone County, McHenry County, Winnebago County, Illinois. It was in force for 34 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
Apr 9, 2013, 9:26 AM CDT (14:26 UTC)
Expired
Apr 9, 2013, 10:00 AM CDT
In force
34 min
Issued by
NWS Chicago, IL
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

Counties Boone County, IL, McHenry County, IL, Winnebago County, IL

The radar

The Milwaukee radar (KMKX), 74 km from the middle of the area, began a volume at 14:25 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

Davenport, (KDVN), launched 12:00Z, 2.4 hours before the alert went out and 160 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, Davenport, at 12:00Z on 2013-04-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Davenport, at 12:00Z on 2013-04-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 291 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
460 m above ground
0-6 km bulk shear
57 kt
0-1 km storm-relative helicity
291 m²/s²
0-3 km storm-relative helicity
425 m²/s²
Significant tornado parameter
0.0
Supercell composite
5.1

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 Apr 9, 9:13 AM CDT, 13 minutes earlier.

Area forecast discussion, Apr 9, 9:13 AM CDT, 13 minutes before
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Hazardous weather outlook, Apr 9, 5:10 AM CDT, 4 hours 16 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
510 AM CDT TUE APR 9 2013

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
101015-
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-
510 AM CDT TUE APR 9 2013 /610 AM EDT TUE APR 9 2013/

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

.DAY ONE...TODAY AND TONIGHT.

  WEATHER HAZARDS EXPECTED:

  DENSE FOG.

  THUNDERSTORMS...THE MOST INTENSE MAY PRODUCE:
    HAIL UP TO THE SIZE OF GOLF BALLS.
    DAMAGING WINDS IN EXCESS OF 60 MPH.
    VERY HEAVY RAIN.
    AND FREQUENT CLOUD TO GROUND LIGHTNING.

  AREAS AFFECTED AND TIMING:

  PATCHY DENSE FOG IS LIKELY ALONG THE ILLINOIS LAKE MICHIGAN
  SHORE...MAINLY THIS MORNING. DENSE FOG IS POSSIBLE
  TONIGHT...ESPECIALLY NORTH OF INTERSTATE 80.

  SCATTERED THUNDERSTORMS ARE EXPECTED EARLY THIS MORNING...MAINLY
  NORTH OF INTERSTATE 80.

  ADDITIONAL SCATTERED THUNDERSTORMS...WITH SOME POTENTIAL FOR
  SEVERE WEATHER...MAY DEVELOP THIS AFTERNOON INTO EARLY THIS
  EVENING...THE GREATEST POTENTIAL IS NORTH OF A PONTIAC TO
  RENSSELAER LINE.

  FINALLY...THUNDERSTORM CHANCES WILL INCREASE FROM WEST TO EAST
  ACROSS THE OUTLOOK AREA AFTER 1 AM TONIGHT.

  DISCUSSION:

  SCATTERED THUNDERSTORMS WILL AFFECT PORTIONS OF FAR NORTHERN
  ILLINOIS THIS MORNING WITH THE STRONGEST STORMS CAPABLE OF
  PRODUCING SOME SMALL HAIL AND HEAVY DOWNPOURS.

  A STRONG WARM FRONT WILL STALL OUT OVER THE REGION THIS
  AFTERNOON WITH VERY WARM AND HUMID AIR ALONG AND SOUTH OF THE
  FRONT. A WEAK UPPER LEVEL DISTURBANCE WILL TRACK INTO THE REGION
  LATE THIS AFTERNOON AND EVENING...LEADING TO THE POTENTIAL FOR
  ISOLATED TO SCATTERED THUNDERSTORMS TO DEVELOP. GIVEN THE
  FORECAST INSTABILITY AND STRONG WINDS ALOFT THE POTENTIAL WILL
  EXIST FOR ANY STORMS THAT DO FORM TO BECOME SEVERE WITH THE
  POTENTIAL FOR LARGE HAIL AND DAMAGING WINDS.

  FINALLY...A LARGE AREA OF SHOWERS AND THUNDERSTORMS THAT FORM
  OVER THE PLAINS THIS AFTERNOON COULD MOVE INTO MAINLY WESTERN
  PORTIONS OF THE OUTLOOK AREA LATE TONIGHT. THE PRIMARY THREAT
  FROM THUNDERSTORMS LATE TONIGHT WOULD BE HEAVY RAIN.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

SOME PERIODS OF THUNDERSTORMS ARE LIKELY WEDNESDAY INTO WEDNESDAY
NIGHT. THE POTENTIAL DOES EXISTS FOR SOME OF THE THUNDERSTORMS TO
BECOME SEVERE...ESPECIALLY SOUTH OF INTERSTATE 80 WEDNESDAY
NIGHT. HEAVY RAINFALL TOTALS ARE POSSIBLE THROUGH THURSDAY...WHICH
COULD RESULT IN SOME POTENTIAL FOR LOCALIZED FLOODING AND RISES ON
AREA RIVERS AND STREAMS.

THERE IS ANOTHER CHANCE OF THUNDERSTORMS SATURDAY NIGHT THROUGH
SUNDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS MAY BE NEEDED THIS AFTERNOON AND EVENING.

&&

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

LMZ740>745-101015-
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-
510 AM CDT TUE APR 9 2013

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

.DAY ONE...TODAY AND TONIGHT.

PERIODIC THUNDERSTORM CHANCES WILL EXIST THROUGH TONIGHT WITH SOME
POTENTIAL FOR SEVERE THUNDERSTORMS WITH WINDS OVER 35 KT AND LARGE
HAIL THIS AFTERNOON AND EVENING.

AREAS OF DENSE FOG ARE LIKELY.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

PATCHY DENSE FOG IS LIKELY INTO WEDNESDAY MORNING.

PERIODS OF THUNDERSTORMS WILL CONTINUE WEDNESDAY AND WEDNESDAY
NIGHT WITH SOME POTENTIAL FOR SEVERE THUNDERSTORMS...MAINLY
WEDNESDAY NIGHT.

STRONG WINDS AND HIGH WAVES WILL LEAD TO HAZARDOUS CONDITIONS FOR
SMALL CRAFT ALONG THE ILLINOIS SHORE WEDNESDAY...AND ALONG THE
ILLINOIS AND INDIANA SHORE WEDNESDAY NIGHT THROUGH FRIDAY.

&&

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-
870-872-874-876-878-101015-
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-
510 AM CDT TUE APR 9 2013

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

.DAY ONE...TODAY AND TONIGHT.

SCATTERED THUNDERSTORMS ARE LIKELY THROUGH TONIGHT...ESPECIALLY
SOUTHERN PORTIONS OF THE LAKE.

AREAS OF DENSE FOG ARE LIKELY...ESPECIALLY SOUTHERN PORTIONS OF
THE LAKE.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

PATCHY DENSE FOG IS LIKELY WEDNESDAY MORNING...ESPECIALLY SOUTH.

PERIODS OF THUNDERSTORMS ARE LIKELY WEDNESDAY AND WEDNESDAY
NIGHT...ESPECIALLY SOUTHERN PORTIONS OF THE LAKE.

GALE FORCE WINDS ARE POSSIBLE WEDNESDAY NIGHT INTO THURSDAY.

&&

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

IZZI

In the hours before

Special weather statement, Apr 9, 3:29 AM CDT, 5 hours 57 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
329 AM CDT TUE APR 9 2013

ILZ008-090900-
OGLE IL-
329 AM CDT TUE APR 9 2013

...SPECIAL WEATHER STATEMENT...

AT 328 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR SHANNON...MOVING NORTHEAST AT 20 MPH.

NICKEL SIZE HAIL...CONTINUOUS CLOUD TO GROUND LIGHTNING...BRIEF HEAVY
DOWNPOURS...ARE POSSIBLE WITH THIS STORM.

CITIES AND TOWNS AFFECTED...
  FORRESTON...
  AND RURAL NORTHWEST OGLE COUNTY...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 4220 8969 4220 8940 4205 8969 4220 8970
TIME...MOT...LOC 0828Z 225DEG 17KT 4213 8973
Local storm report, Apr 9, 8:51 AM CDT, 35 minutes before
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Special weather statement, Apr 9, 9:16 AM CDT, 10 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Apr 9, 12:20 AM CDTDense Fog AdvisoryLOTLake11 hr
Apr 9, 12:22 AM CDTMarine Dense Fog AdvisoryLOT27 hr
Apr 9, 3:29 AM CDTSpecial Weather StatementLOTOgle31 min
Apr 9, 9:16 AM CDTSpecial Weather StatementLOTWinnebago29 min
Apr 9, 9:44 AM CDTSmall Craft AdvisoryLOT4 days
Apr 9, 9:48 AM CDTRiver Flood WatchLOTWinnebago25 hr
Apr 9, 9:48 AM CDTRiver Flood WatchLOTWinnebago25 hr
Apr 9, 9:48 AM CDTRiver Flood WatchLOTWinnebago25 hr
Apr 9, 3:54 PM CDTGale WatchLOT12 hr
Apr 8, 7:35 PM CDTSpecial Weather StatementLOTBenton25 min
Apr 8, 9:42 PM CDTSpecial Weather StatementLOTBenton33 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2013Every severe thunderstorm warning in 2013

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.