Alert archive / Illinois / Severe Thunderstorm Warnings in 2014

Severe Thunderstorm Warning 25, NWS Chicago, IL

May 12, 2014LaSalle County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at May 12, 2014, 5:53 PM CDT for LaSalle County, Illinois. It was in force for 67 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
May 12, 2014, 5:53 PM CDT (22:53 UTC)
Expired
May 12, 2014, 7:00 PM CDT
In force
67 min
Issued by
NWS Chicago, IL
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County LaSalle County, IL

The radar

The Chicago radar (KLOT), 73 km from the middle of the area, began a volume at 22:54 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
May 12, 3:49 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 10.9 hours before the alert went out and 135 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, Lincoln, IL at 12:00Z on 2014-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1710 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, Lincoln, IL at 12:00Z on 2014-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 212 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
1710 J/kg
Mixed-layer CIN
-43 J/kg
Mixed-layer LCL
785 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
212 m²/s²
0-3 km storm-relative helicity
200 m²/s²
Significant tornado parameter
1.3
Supercell composite
6.7

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 May 12, 5:26 PM CDT, 27 minutes earlier.

Area forecast discussion, May 12, 5:26 PM CDT, 27 minutes before
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Hazardous weather outlook, May 12, 4:11 PM CDT, 1 hour 42 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
411 PM CDT MON MAY 12 2014

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
132115-
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-
411 PM CDT MON MAY 12 2014 /511 PM EDT MON MAY 12 2014/

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

.DAY ONE...TONIGHT.

  WEATHER HAZARDS EXPECTED:

  THUNDERSTORMS...THE MOST INTENSE COULD PRODUCE:
    WIND GUSTS OVER 60 MPH.
    HAIL UP TO THE SIZE OF GOLF BALLS.
    TORRENTIAL DOWNPOURS.
    AND FREQUENT CLOUD TO GROUND LIGHTNING.

  AREAS AFFECTED AND TIMING:

  SCATTERED THUNDERSTORMS WILL CONTINUE ACROSS NORTHERN ILLINOIS
  THIS EVENING. ADDITIONAL THUNDERSTORMS WILL SPREAD ACROSS AREAS
  WEST OF INTERSTATE 55 DURING THE MIDDLE TO LATE EVENING AND THEN
  ACROSS THE REST OF THE AREA OVERNIGHT.

  DISCUSSION:

  THE PRESENCE OF A MOIST AND UNSTABLE AIR MASS WILL FAVOR
  SCATTERED THUNDERSTORMS THROUGH THIS EVENING WHICH MAY PRODUCE
  LARGE HAIL AND DAMAGING WIND GUSTS. A COLD FRONT WILL MOVE
  ACROSS THE REGION LATER TONIGHT INTO TUESDAY MORNING. ADDITIONAL
  THUNDERSTORMS ARE EXPECTED TO DEVELOP AHEAD OF THIS FRONT AND
  MOVE ACROSS THE AREA FROM MID TO LATE EVENING INTO THE OVERNIGHT
  HOURS. WHILE THESE THUNDERSTORMS WILL LIKELY BEGIN TO WEAKEN BY
  LATE EVENING...THERE IS A POTENTIAL THAT THEY COULD STILL POSE A
  SEVERE THREAT AS THEY INTO NORTH CENTRAL ILLINOIS.

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

THERE IS A CHANCE OF THUNDERSTORMS TUESDAY MORNING.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS WILL BE NEEDED THIS EVENING.

&&

LMZ740>745-132115-
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-
411 PM CDT MON MAY 12 2014

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

.DAY ONE...TONIGHT.

STRONG WINDS HAZARDOUS TO SMALL CRAFT WILL CONTINUE THROUGH THIS
EVENING.

THUNDERSTORMS WILL INCREASE IN COVERAGE THIS EVENING AND CONTINUE
OVERNIGHT. SOME OF THE STORMS COULD PRODUCE HAIL UP TO 1 INCH IN
DIAMETER AND WIND GUSTS OVER 35 KNOTS.

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

THERE IS A CHANCE OF THUNDERSTORMS TUESDAY MORNING.

&&

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-132115-
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-
411 PM CDT MON MAY 12 2014

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

.DAY ONE...TONIGHT.

OCCASIONAL THUNDERSTORMS ARE EXPECTED...WITH SOME POSSIBLY PRODUCING
LARGE HAIL AND WIND GUSTS OVER 35 KNOTS.

DENSE FOG IS POSSIBLE OVER THE NORTHERN HALF OF THE LAKE.

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

THERE IS A CHANCE OF THUNDERSTORMS TUESDAY MORNING.

&&

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

Local storm report, May 12, 3:24 PM CDT, 2 hours 29 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
324 PM CDT MON MAY 12 2014

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

0317 PM     HAIL             SOUTH BELOIT            42.48N 89.03W
05/12/2014  E2.00 INCH       WINNEBAGO          IL   TRAINED SPOTTER

            1.5 TO 2 INCH DIAMETER HAIL NEAR ROUTE 2 AND PRAIRIE
            ROAD.

0319 PM     HAIL             SOUTH BELOIT            42.48N 89.03W
05/12/2014  E1.75 INCH       WINNEBAGO          IL   LAW ENFORCEMENT

            QUARTER TO GOLFBALL SIZE HAIL.

&&

The office that day

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

IssuedProductOfficeCountiesLasted
May 11, 7:43 PM CDTSevere Thunderstorm WarningLOTIroquois62 min
May 11, 7:58 PM CDTFlash Flood WarningLOTFord, Livingston3 hr
May 11, 9:15 PM CDTFlash Flood WarningLOTFord, Iroquois6 hr
May 11, 9:16 PM CDTRiver Flood AdvisoryLOTWill53 hr
May 11, 11:09 PM CDTSevere Thunderstorm WarningLOTFord, Iroquois51 min
May 12, 9:09 AM CDTSmall Craft AdvisoryLOT12 hr
May 12, 9:34 AM CDTMarine Dense Fog AdvisoryLOT23 hr
May 12, 2:56 PM CDTSevere Thunderstorm WarningLOTBoone, Winnebago49 min
May 12, 6:15 PM CDTSpecial Weather StatementLOTLake45 min
May 12, 6:20 PM CDTSpecial Marine WarningLOT85 min
May 12, 6:27 PM CDTSevere Thunderstorm WarningLOTCook, Lake48 min
May 12, 6:32 PM CDTSevere Thunderstorm WarningLOTDeKalb, LaSalle58 min
May 12, 6:39 PM CDTSevere Thunderstorm WarningLOTCook, DuPage36 min
May 11, 7:03 PM CDTSevere Thunderstorm WarningLOTPorter42 min
May 11, 7:39 PM CDTFlash Flood WarningLOTJasper, Lake, Newton, Porter6 hr
May 11, 7:54 PM CDTTornado WarningLOTJasper, Newton51 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.