Alert archive / Illinois / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 70, NWS Chicago, IL

June 15, 2015DeKalb County, LaSalle County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jun 15, 2015, 5:39 PM CDT for DeKalb County, LaSalle County, Illinois. It was in force for 21 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 15, 2015, 5:39 PM CDT (22:39 UTC)
Expired
Jun 15, 2015, 6:00 PM CDT
In force
21 min
Issued by
NWS Chicago, IL
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties DeKalb County, IL, LaSalle County, IL

The radar

The Chicago radar (KLOT), 62 km from the middle of the area, began a volume at 22:43 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, 10.7 hours before the alert went out and 139 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 2015-06-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 280 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 12:00Z on 2015-06-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 8 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
280 J/kg
Mixed-layer CIN
-29 J/kg
Mixed-layer LCL
660 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
8 m²/s²
0-3 km storm-relative helicity
63 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

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 15, 4:55 PM CDT, 44 minutes earlier.

Area forecast discussion, Jun 15, 4:55 PM CDT, 44 minutes before
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Hazardous weather outlook, Jun 15, 3:39 PM CDT, 2 hours before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
339 PM CDT MON JUN 15 2015

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
162045-
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-
339 PM CDT MON JUN 15 2015

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

.DAY ONE...TONIGHT.

  WEATHER HAZARDS EXPECTED:

  THUNDERSTORMS...SOME OF WHICH MAY PRODUCE:

   FREQUENT CLOUD TO GROUND LIGHTNING.
   VERY HEAVY RAINFALL AND FLASH FLOODING.
   ISOLATED WINDS GUSTS ABOVE 60 MPH.

  AREAS AFFECTED AND TIMING:

   SCATTERED THUNDERSTORMS WILL LIKELY GROW MORE NUMEROUS ACROSS
   THE OUTLOOK AREA THROUGH THIS EVENING. THE MAIN CONCENTRATION
   OF THUNDERSTORMS WILL GRADUALLY SHIFT SOUTH OVERNIGHT AND
   END NORTH OF INTERSTATE 80 DURING THE PRE-DAWN HOURS.

  DISCUSSION:

   THUNDERSTORMS WILL BECOME MORE NUMEROUS THROUGH THE EVENING AS
   A SLOW MOVING FRONT APPROACHES THE AREA. THE ATMOSPHERE IS
   EXTREMELY MOIST AND ANY STORMS THAT FORM WILL HAVE THE
   POTENTIAL TO PRODUCE TORRENTIAL DOWNPOURS...POTENTIALLY
   UPWARDS OF 2 INCHES IN AN HOUR OR LESS. IN ADDITION TO THE
   HEAVY RAIN...WHICH MAY RESULT IN LOCALIZED FLASH FLOODING...A
   COUPLE OF THE STORMS COULD PRODUCE LOCALIZED WIND GUSTS OVER
   60 MPH.

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

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

THERE WILL BE PERIODIC CHANCES OF THUNDERSTORMS TUESDAY THROUGH
THE WEEKEND.

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

.SPOTTER INFORMATION STATEMENT...

DUE TO THE ISOLATED NATURE OF THE SEVERE WEATHER THREAT...SPOTTER
ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT...HOWEVER ANY
OBSERVATIONS OF FLOODING OR MEASURED HEAVY RAIN TOTALS WOULD BE
APPRECIATED.

&&

LMZ740>745-162045-
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-
339 PM CDT MON JUN 15 2015

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

.DAY ONE...TONIGHT.

PERIODS OF THUNDERSTORMS ARE EXPECTED THROUGH LATE TONIGHT. SOME
OF THE STORMS MAY PRODUCE GUSTS UP TO 35 KNOTS.

AREAS OF FOG ARE POSSIBLE THROUGH THIS EVENING.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

THERE ARE PERIODIC CHANCES OF THUNDERSTORMS LATE TUESDAY NIGHT
THROUGH THE WEEKEND.

&&

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-162045-
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-
339 PM CDT MON JUN 15 2015

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

.DAY ONE...TONIGHT.

PERIODS OF THUNDERSTORMS ARE EXPECTED ACROSS MUCH OF THE LAKE
THROUGH LATE TONIGHT.

AREAS OF DENSE FOG ARE LIKELY INTO EARLY THIS EVENING.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

THERE ARE PERIODIC CHANCES OF THUNDERSTORMS WEDNESDAY THROUGH THE
WEEKEND.

&&

KREIN

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

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

In the hours before

Special weather statement, Jun 15, 2:49 PM CDT, 2 hours 50 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
249 PM CDT MON JUN 15 2015

INZ011-152015-
JASPER IN-
249 PM CDT MON JUN 15 2015

...SPECIAL WEATHER STATEMENT FOR CENTRAL JASPER COUNTY UNTIL 315 PM
CDT...

AT 248 PM CDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR
GIFFORD...MOVING EAST AT 25 MPH.

WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THIS STORM.

THIS STRONG THUNDERSTORM WILL BE NEAR...
  MOODY AROUND 300 PM CDT.
  HANGING GROVE AND MCCOYSBURG AROUND 305 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

&&

LAT...LON 4091 8699 4088 8699 4096 8721 4113 8714
      4110 8693 4091 8693
TIME...MOT...LOC 1948Z 291DEG 22KT 4103 8708

IZZI
Local storm report, Jun 15, 3:42 PM CDT, 1 hour 57 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
342 PM CDT MON JUN 15 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0335 PM     HEAVY RAIN       2 N RENSSELAER          40.96N 87.15W
06/15/2015  M0.90 INCH       JASPER             IN   COCORAHS

            RAINFALL IN 35 MINUTES.

&&

BN
Local storm report, Jun 15, 3:57 PM CDT, 1 hour 42 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
357 PM CDT MON JUN 15 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0345 PM     HEAVY RAIN       6 E ASHKUM              40.88N 87.84W
06/15/2015  M2.07 INCH       IROQUOIS           IL   COCORAHS

            RAINFALL SINCE 6AM WITH 1.75 INCHES IN THE PAST 60
            MINUTES.

&&

BN
Local storm report, Jun 15, 4:03 PM CDT, 1 hour 36 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
403 PM CDT MON JUN 15 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0352 PM     TSTM WND GST     4 SSE FORESMAN          40.82N 87.26W
06/15/2015  M48.00 MPH       JASPER             IN   TRAINED SPOTTER

&&

BB
Local storm report, Jun 15, 4:06 PM CDT, 1 hour 33 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
406 PM CDT MON JUN 15 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0400 PM     FLOOD            1 N ROCHELLE            41.93N 89.06W
06/15/2015                   OGLE               IL   TRAINED SPOTTER

            WATER OVER CURBS...1-2 FEET DEEP OF STANDING WATER AT RT
            38 AND TURKINGTON TERRACE

&&

BB
Local storm report, Jun 15, 5:17 PM CDT, 22 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jun 14, 7:29 PM CDTAreal Flood AdvisoryLOTFord, Livingston4 hr
Jun 14, 8:40 PM CDTRiver Flood AdvisoryLOTIroquois3 days
Jun 15, 4:10 AM CDTFlash Flood WatchLOTBoone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more24 hr
Jun 15, 9:23 AM CDTRiver Flood AdvisoryLOTBoone58 hr
Jun 15, 10:13 AM CDTRiver Flood AdvisoryLOTKane, McHenry45 hr
Jun 15, 10:13 AM CDTRiver Flood AdvisoryLOTKane, Kendall4 days
Jun 15, 10:13 AM CDTRiver Flood AdvisoryLOTLaSalle62 hr
Jun 15, 10:32 AM CDTFlash Flood WarningLOTGrundy, LaSalle6 hr
Jun 15, 10:47 AM CDTSevere Thunderstorm WarningLOTDeKalb, Lee26 min
Jun 15, 11:00 AM CDTFlash Flood WarningLOTKankakee, Will6 hr
Jun 15, 11:51 AM CDTSpecial Weather StatementLOTDuPage24 min
Jun 15, 2:29 PM CDTAreal Flood AdvisoryLOTFord, Iroquois, Kankakee, Livingston2 hr
Jun 15, 3:08 PM CDTFlash Flood WarningLOTIroquois, Kankakee6 hr
Jun 15, 4:24 PM CDTFlash Flood WarningLOTCook, DeKalb, DuPage, Kane, Lee, Ogle6 hr
Jun 15, 4:41 PM CDTAreal Flood WarningLOTGrundy, Kankakee, LaSalle, Will18 hr
Jun 15, 4:50 PM CDTTornado WarningLOTCook25 min
Jun 15, 5:03 PM CDTSpecial Marine WarningLOT57 min
Jun 15, 6:09 PM CDTFlash Flood WarningLOTCook, DeKalb, DuPage, Grundy, Kendall, LaSalle and 2 more4 hr
Jun 15, 6:28 PM CDTRiver Flood AdvisoryLOTCook25 hr
Jun 15, 6:32 PM CDTSpecial Marine WarningLOT118 min
Jun 15, 11:19 AM CDTSpecial Weather StatementLOTLake26 min
Jun 15, 11:42 AM CDTAreal Flood AdvisoryLOTLake, Porter2 hr
Jun 15, 2:49 PM CDTSpecial Weather StatementLOTJasper26 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2015Every severe thunderstorm warning in 2015

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.