Alert archive / Illinois / Severe Thunderstorm Warnings in 2014

Severe Thunderstorm Warning 77, NWS Chicago, IL

June 30, 2014Boone County, McHenry County, Winnebago County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jun 30, 2014, 12:21 AM CDT for Boone County, McHenry County, Winnebago County, Illinois. It was in force for 54 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
Jun 30, 2014, 12:21 AM CDT (05:21 UTC)
Expired
Jun 30, 2014, 1:15 AM CDT
In force
54 min
Issued by
NWS Chicago, IL
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
60.0 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 05:22 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jun 29, 10:54 PM CDTTornado WatchSPC5 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 5.4 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 00:00Z on 2014-06-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1816 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, Davenport, at 00:00Z on 2014-06-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 74 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
1816 J/kg
Mixed-layer CIN
-89 J/kg
Mixed-layer LCL
1110 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
74 m²/s²
0-3 km storm-relative helicity
126 m²/s²
Significant tornado parameter
0.5
Supercell composite
5.6

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 Jun 30, 12:15 AM CDT, 6 minutes earlier.

Area forecast discussion, Jun 30, 12:15 AM CDT, 6 minutes before
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Hazardous weather outlook, Jun 29, 11:52 PM CDT, 29 minutes before
HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1152 PM CDT SUN JUN 29 2014

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
010500-
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-
1152 PM CDT SUN JUN 29 2014 /1252 AM EDT MON JUN 30 2014/

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

.DAY ONE...OVERNIGHT.

  WEATHER HAZARDS EXPECTED:

  THUNDERSTORMS...SOME OF WHICH MAY PRODUCE:

   HEAVY DOWNPOURS.
   FREQUENT CLOUD TO GROUND LIGHTNING.
   WIND GUSTS OF 70 TO 80 MPH.
   QUARTER SIZE HAIL
   POSSIBLY A TORNADO.

  AREAS AFFECTED AND TIMING:

  THUNDERSTORMS WILL CONTINUE TO MOVE EASTWARD FROM NORTHWEST
  ILLINOIS AND EASTERN IOWA THROUGH OVERNIGHT. WHILE A SLOW
  WEAKENING TREND CONTINUES TO BE EXPECTED...SOME STORMS HAVE
  SHOWN POTENTIAL TO HAVE STRONG WINDS AND EVEN ROTATION CAPABLE
  OF TORNADOES. STORMS SHOULD GRADUALLY MOVE INTO NORTHEAST
  ILLINOIS AND POSSIBLY NORTHWEST INDIANA LATE AND INTO THE
  PREDAWN HOURS.

  DISCUSSION:

  THE AIR MASS ACROSS THE REGION CONTINUES TO BE MOIST WITH A
  GREAT DEAL OF INSTABILITY...ENOUGH TO AT LEAST PROVIDE THE
  POTENTIAL FOR SURFACE BASED STORMS IN NORTH CENTRAL ILLINOIS.
  THUS STRONG WINDS AND POSSIBLY A TORNADO OR TWO REMAIN THREATS
  WITH THIS BROKEN LINE OF STORMS AS IT MOVES INTO AND THROUGH
  NORTH CENTRAL ILLINOIS.

PORTIONS OF THE IROQUOIS AND KANKAKEE RIVERS WILL REMAIN IN
FLOOD.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

THUNDERSTORMS ARE LIKELY LATER MONDAY AFTERNOON AND NIGHT...WITH
THE INCREASING LIKELIHOOD FOR SEVERE STORMS IN THE REGION. STRONG
DAMAGING WINDS...TORNADOES...LARGE HAIL...AND LOCALLY HEAVY
RAINFALL WILL ALL BE POSSIBLE WITH THESE STORMS.

WATER LEVELS WILL REMAIN HIGH ALONG PORTIONS OF THE KANKAKEE
RIVER  THROUGH AT LEAST THE MIDDLE OF THE WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS REQUESTED ACROSS NORTH CENTRAL ILLINOIS
THROUGH EARLY OVERNIGHT. ACTIVATION WILL LIKELY BE NEEDED ACROSS
MUCH OF THE AREA LATE MONDAY AFTERNOON INTO THE EVENING.

&&

LMZ740>745-010500-
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-
1152 PM CDT SUN JUN 29 2014

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

.DAY ONE...OVERNIGHT.

SCATTERED THUNDERSTORMS ARE POSSIBLE. SOME STORMS MAY PRODUCE
STRONG GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

THUNDERSTORMS ARE LIKELY MONDAY AFTERNOON AND NIGHT...WITH THE
POTENTIAL FOR SEVERE STORMS.

STRONG WINDS MAY LEAD TO HAZARDOUS CONDITIONS FOR SMALL CRAFT
MONDAY AFTERNOON AND AGAIN TUESDAY AFTERNOON.

&&

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-010500-
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-
1152 PM CDT SUN JUN 29 2014

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

.DAY ONE...TONIGHT.

AREAS OF DENSE FOG ESPECIALLY OVER PORTIONS OF CENTRAL AND
NORTHERN LAKE MICHIGAN TONIGHT.

THERE IS A CHANCE OF THUNDERSTORMS...SOME OF WHICH MAY PRODUCE
STRONG WINDS ACROSS THE FAR SOUTHERN PART OF THE LAKE.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

THUNDERSTORMS ARE LIKELY ACROSS THE LAKE MONDAY AND MONDAY
NIGHT...WITH SEVERE STORMS POSSIBLE OVER THE SOUTHERN HALF OF
THE LAKE DURING THE AFTERNOON AND EVENING HOURS.

AREAS OF DENSE FOG WILL PERSIST THROUGH MONDAY.

&&

MTF

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO

In the hours before

Special weather statement, Jun 30, 12:03 AM CDT, 18 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1203 AM CDT MON JUN 30 2014

ILZ003-004-300530-
BOONE IL-WINNEBAGO IL-
1203 AM CDT MON JUN 30 2014

...SPECIAL WEATHER STATEMENT...

AT MIDNIGHT CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR DURAND...MOVING EAST AT 45 MPH.

DIME SIZE HAIL...WINDS TO 50 MPH...CONTINUOUS CLOUD TO
GROUND LIGHTNING...AND BRIEF TORRENTIAL DOWNPOURS...ARE POSSIBLE
WITH THIS STORM.

CITIES AND TOWNS AFFECTED...
  DURAND...             LAKE SUMMERSET...     PECATONICA...
  ROCKTON...            SOUTH BELOIT...       MACHESNEY PARK...
  ROSCOE...             LOVES PARK...

OTHER LOCATIONS AFFECTED...
ROCK CUT STATE PARK...ROCK VALLEY COLLEGE...ROCKFORD RIVERHAWKS
BASEBALL...ROCKFORD SPEEDWAY...WINNEBAGO COUNTY FAIRGROUNDS...

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 THIS STORM
HAS PASSED.

&&

LAT...LON 4250 8890 4227 8890 4231 8941 4250 8941
      4250 8940 4250 8926
TIME...MOT...LOC 0503Z 271DEG 35KT 4244 8929

BIRK

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 30, 12:03 AM CDTSpecial Weather StatementLOTWinnebago27 min
Jun 30, 12:34 AM CDTSevere Thunderstorm WarningLOTLee, Ogle56 min
Jun 30, 1:16 AM CDTSevere Thunderstorm WarningLOTDeKalb, LaSalle, Lee, Ogle44 min
Jun 30, 1:23 AM CDTAreal Flood AdvisoryLOTBoone, Winnebago6 hr
Jun 30, 1:50 AM CDTTornado WarningLOTMcHenry40 min
Jun 30, 1:57 AM CDTSpecial Weather StatementLOTDeKalb, Kane, Kendall33 min
Jun 30, 2:31 AM CDTSpecial Weather StatementLOTLake29 min
Jun 30, 2:52 AM CDTSpecial Weather StatementLOTLaSalle23 min
Jun 30, 3:12 AM CDTSpecial Weather StatementLOTGrundy, Livingston33 min
Jun 30, 3:45 AM CDTSpecial Weather StatementLOTLake45 min
Jun 30, 3:52 AM CDTSpecial Marine WarningLOT83 min
Jun 30, 4:12 AM CDTFlash Flood WatchLOTBoone, DeKalb, DuPage, Grundy, Kane, Kankakee and 8 more21 hr
Jun 30, 4:35 AM CDTAreal Flood AdvisoryLOTGrundy, LaSalle, Livingston4 hr
Jun 30, 5:51 AM CDTSevere Thunderstorm WarningLOTFord, Iroquois, Livingston54 min
Jun 30, 6:21 AM CDTSpecial Marine WarningLOT54 min
Jun 30, 6:30 AM CDTSevere Thunderstorm WarningLOTFord, Iroquois60 min
Jun 30, 6:44 AM CDTAreal Flood AdvisoryLOTFord, Iroquois, Livingston6 hr
Jun 30, 10:03 AM CDTRiver Flood WatchLOTWinnebago8 days
Jun 30, 10:03 AM CDTRiver Flood WatchLOTWinnebago7 days
Jun 30, 10:03 AM CDTRiver Flood WatchLOTOgle5 days
Jun 30, 10:03 AM CDTRiver Flood WatchLOTWinnebago4 days
Jun 30, 11:08 AM CDTRiver Flood WatchLOTLake7 days
Jun 30, 11:27 AM CDTRiver Flood WatchLOTLaSalle4 days
Jun 30, 12:27 PM CDTRiver Flood AdvisoryLOTKane, Kendall7 days
Jun 30, 3:47 PM CDTSpecial Weather StatementLOTBoone, Cook, DeKalb, DuPage, Grundy, Kane and 10 more43 min
Jun 30, 4:53 PM CDTAreal Flood AdvisoryLOTLee, Ogle, Winnebago6 hr
Jun 30, 5:30 PM CDTSpecial Marine WarningLOT2 hr
Jun 30, 6:14 PM CDTSevere Thunderstorm WarningLOTCook, DeKalb, DuPage, Kane, Kendall, Will61 min
Jun 30, 6:22 PM CDTSpecial Marine WarningLOT113 min
Jun 30, 6:24 PM CDTAreal Flood AdvisoryLOTCook, DuPage, Kane, Kendall, Lake, Will4 hr
Jun 30, 6:48 PM CDTSevere Thunderstorm WarningLOTKendall, Will27 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2014Every severe thunderstorm warning in 2014

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.