Damaging Winds in Indiana, July 18, 2007

Name: Damaging Winds in Indiana, July 18, 2007
Start: 2007-07-18T21:00
End: 2007-07-18T22:23
Location: Indiana

July 18, 2007 · NWS LOT · 2 events in 2 counties and zones

Strong to severe storms moved across northwest Indiana during the evening hours of July 18th.

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $10,000
Crop damage: None recorded
Events: 2

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS LOT wrote it up.

Strong to severe storms moved across northwest Indiana during the evening hours of July 18th.

What forecasters said that day

The local office's own words before the first event, 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 the first event at Jul 18, 6:00 PM CST, 3 hours earlier.

Area forecast discussion, Jul 18, 6:00 PM CST, 3 hours before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
700 PM CDT WED JUL 18 2007

.DISCUSSION...220PM
COMPLEX AND POTENTIALLY POTENT SITN CONTINUING WITH ASSORTED THREATS
DURING THE NOCTURAL HRS. LAST NIGHTS RAIN FROM OGLE AND LEE COUNTIES
SEWD INTO LASALLE AND LIVINGSTON COUNTIES MAKE THESE AREAS VERY
VULNERABLE TO ADDITIONAL RAIN AND SUBSEQUENT FLOODING TNGT AND
THURSDAY.

UPPER TROUGH WHICH HAS SUPPORTED SEWD MOVING MCS SYSTEMS PAST 2 DAYS
WILL BE BUCKLING LATER TONIGHT AND THURSDAY WITH SHORT WAVE PIVOTING
SWD FROM MANITOBA THROUGH THE MIDWEST DRAGGING COOLER AIR INTO
REGION LATER THURSDAY.  SECOND IMPULSE IS MOVING OUT OF THE WESTERN
DAKS THIS AFTN AND WILL SLIDE ESE AHEAD OF HIGHER AMPLITUDE DEVELMT.
THIS LATTER SYSTEM IS NOW BEGINNING TO INTERACT WITH BAROCLINIC ZONE
STRETCHING FROM SE SDAK ACROSS NRN IOWA INTO SRN WISC.  VERY MOSIT
AIR SOUTH OF THIS BOUNDARY WILL BE THE FUEL FOR TSTMS/MCS EXPECTED
TO FORM OVER WRN IOWA OR SW MINN DURING THE LATE AFTN.  WHOLE FLOW
PATTERN IS NOW MORE E-W SO EXPECT ANY ORGANIZED CONVECTION TO MOVE
TWD NRN ILL DURING THE NIGHT.  AVAILABLE ACARS SOUNDINGS AND MODEL
SOUNDINGS FROM ORD WESTWARD ACROSS IOWA SHOW A CONTINUED VERY DEEP
NEARLY ADIABATIC LAPSE RATE IN AN ELEVATED ZONE ABOVE 850MB.
POCKETS OF DRY AIR ALSO SEEN IN THESE WHICH SUGGESTS BOTH STRONG
BUOYANCY AS WELL AS WIND POTENTIAL.

AT THIS POINT EXPECT CONVECTION SHOULD ORGANIZE ALONG THE IOWA/MINN
BORDER MORE OR LESS..AND TRACK EAST OR ESE INTO NRN ILLINOIS DURING
THE LATE EVENING OR AFTER MIDNIGHT. CANNOT IGNORE SLOW APPROACH OF
MAIN CANADIAN FRONT INTO NRN WISC WHICH MAY INITIATE ITS OWN ZONE OF
CONVECTION BUT AT THIS POINT THE SHORT WAVE ENHANCED CONVECTION FROM
THE WEST IS OF MORE CONCERN.

FLOODING...SOUTH AND WESTERN PORTIONS OF CWA SATURATED. DIFFERENCE
IN TONIGHTS SITUATION IS A BETTER INFLOW EXPECTED ACROSS IOWA AND
NRN MISSOURI. 925MB AND 850MB MODEL WINDS ARE WELL ORGANIZED DURING
THE NIGHT WITH UP TO 35KTS SEEN ON THE NAM80. THUS LOW LEVEL FORCING
OF MOIST AIR INTO CONVECTIVE CLUSTERS MAY IMPROVE RAIN PRODUCTION.
WILL LEAVE FFA AS IS FOR NOW IT BOTH TIME...12Z THUR...AND AREA.
PRECIP WILL FADE OFF TO THE SE THUSDAY AFTERNOON.

FROM FRIDAY ONWARD ALL GUIDANCE SUGGESTS A LARGE SLOW MOVING
ANTICYCLONE WILL PARK OVER THE MIDWEST WITH SLOW MODIFICATION OF
TEMPS AFTER SUNDAY. NO READON TO ARGUE AS UPPER AIR PATTERN FEATURES
A HIGH AMPLITUDE RIDGE FROM THE PLAINS INTO THE MIDWEST.  KML

&&

.AVIATION...

00Z TAFS...AREA OF THUNDERSTORMS DEVELOPING ACROSS FAR NORTHERN IL
ACROSS THE PAST HR AND CONINTUING TO EXPAND TO THE SE. HAVE CARRIED
TEMPO TS FOR THE FIRST FEW HRS WITH THE EXPECTATION THAT THIS
ACTIVITY WOULD BE PUSHING EAST OF THE TERMINALS. BUT DEVELOPMENT
CONTINUES ACROSS NW IL/SW WI SO THIS WILL LIKELY NEED TO BE ADJUSTED
AS THE EVENING GOES ON. SECOND TEMPO TS WAS FOR THE MAIN LINE OF TS
ACROSS IA WHICH...NOW APPEARS LIKE IT WILL PUSH SOUTHEAST...MAINLY
SOUTH OF THE TAFS DURING THE LATE EVENING AND EARLY MORNING HRS BUT
RAIN WITH EMBEDDED TS STILL LOOKS REASONABLE. PRECIP CHANCES AROUND
SUNRISE QUESTIONABLE AND WILL NEED TO BE LOOKED AT WITH NEXT SET OF
TAFS. FRONT MOVES THRU THE AREA LATE THURSDAY MORNING SHIFTING WINDS
NORTH...THEN SPEEDS INCREASE IN THE AFTERNOON WITH GUSTS 20-25KTS.
CMS

&&

.MARINE DISCUSSION...

245 PM CDT

A WEAK AND DIFFUSE FRONTAL TROUGH FROM SOUTHERN
MINNESOTA...SOUTHEASTWARD ACROSS SOUTHERN LAKE
MICHIGAN WILL REMAIN STATIONARY THROUGH THIS EVENING. MEANWHILE...A
LOW PRESSURE CENTER OVER NEBRASKA WILL MOVE EASTWARD ACROSS THE
UPPER MIDWEST TONIGHT...TO A POSITION NEAR DETROIT BY THURSDAY
MORNING.  AS THIS LOW MOVES EAST OF THE LAKE TONIGHT...A
TRAILING COLD FRONT WILL SURGE SOUTHWARD ACROSS LAKE
MICHIGAN...CLEARING THE SOUTH END OF THE LAKE EARLY THURSDAY
MORNING. IN THE WAKE OF THIS FRONT...A HIGH PRESSURE CENTER WILL
BUILD ACROSS MINNESOTA AND INTO THE WESTERN GREAT LAKES THURSDAY AND
FRIDAY. THIS WILL CREATE HAZARDOUS CONDITIONS FOR SMALL CRAFT ACROSS
SOUTHERN LAKE MICHIGAN FROM THURSDAY AFTERNOON THROUGH FRIDAY DUE TO
NORTH WINDS IN EXCESS OF 20 KNOTS AND WAVES IN EXCESS OF 5 FEET
THROUGH THE PERIOD.

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH UNTIL 12Z THURSDAY FOR OGLE...LEE...LA SALLE...
GRUNDY...LIVINGSTON...IROQUOIS AND FORD.
IN...FLOOD WATCH UNTIL 12Z THURSDAY FOR BENTON.
LM...SMALL CRAFT ADVISORY 15Z THURSDAY THROUGH 03Z SATURDAY.

&&

Hazardous weather outlook, Jul 18, 3:00 PM CST, 6 hours before

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
400 PM CDT WED JUL 18 2007

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
190930-
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-
400 PM CDT WED JUL 18 2007

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

.DAY ONE...TONIGHT.

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS TONIGHT ACROSS MOST
OF NORTHERN ILLINOIS AND A SMALL PORTION OF NORTHWEST INDIANA.
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ELSEWHERE.

THE MODERATE RISK AREA IS ALONG AND SOUTH OF A LINE FROM
ROCKFORD...TO DOWNTOWN CHICAGO...TO PORTAGE INDIANA.

ISOLATED THUNDERSTORMS DURING THE LATE AFTERNOON AND EARLY EVENING
WILL GIVE WAY TO MORE ORGANIZED STORMS MOVING IN FROM THE WEST
TOWARD AND AFTER MIDNIGHT.

THESE STORMS MAY EVOLVE INTO A LINEAR CLUSTER CAPABLE OF PRODUCING
DAMAGING WINDS AS IT MOVES EAST SOUTHEASTWARD INTO NORTHERN ILLINOIS
LATER THIS EVENING.

FLOODING...
HEAVY RAINFALL RESULTING FROM LAST NIGHTS THUNDERSTORMS HAS CAUSED
FLOODING FROM LEE COUNTY ILLINOIS...SOUTHEASTWARD THROUGH THE
PONTIAC AREA.  OVER 5 INCHES OF RAIN WAS REPORTED THROUGH EARLY
THIS MORNING IN THESE AREAS.

DUE TO THE POTENTIAL FOR ADDITIONAL THUNDERSTORM DEVELOPMENT THIS
AFTERNOON AND TONIGHT...THE FLASH FLOOD WATCH FOR SOUTHERN AND
WESTERN PORTIONS OF THE OUTLOOK AREA HAS BEEN EXTENDED UNTIL 7AM
THURSDAY.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

THUNDERSTORMS WILL LIKELY BE ONGOING SOUTH OF THE KANKAKEE AND
ILLINOIS RIVERS THURSDAY MORNING...WITH A CHANCE OF MORNING
THUNDERSTORMS NORTH.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TONIGHT. MEASUREMENTS OF HEAVY
RAINFALL OR REPORTS OF FLOODING WOULD BE APPRECIATED.

&&

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

LMZ740>745-766-190930-
WINTHROP HARBOR TO WILMETTE HARBOR IL-
WILMETTE HARBOR TO NORTHERLY ISLAND IL-
NORTHERLY ISLAND TO CALUMET HARBOR IL-
CALUMET HARBOR IL TO GARY IN-
GARY INDIANA TO BURNS HARBOR-
BURNS HARBOR TO MICHIGAN CITY-
LAKE MICHIGAN OPEN WATERS FROM WINTHROP HARBOR IL EASTWARD TO THE
MID POINT OF THE LAKE AND SOUTHWARD TO MICHIGAN CITY MI BEYOND 5 NM
OFFSHORE-
400 PM CDT WED JUL 18 2007

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

.DAY ONE...TONIGHT.

THUNDERSTORMS ARE LIKELY TONIGHT.  SOME OF THESE STORMS MAY BE
SEVERE WITH WIND GUSTS IN EXCESS OF 34 KNOTS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

HAZARDOUS WINDS AND WAVES FOR SMALL CRAFT ARE EXPECTED TO DEVELOP BY
THURSDAY AFTERNOON...AND CONTINUE INTO FRIDAY.  NORTH WINDS
SUSTAINED AROUND 25 KNOTS WILL LIKELY RESULT IN WAVES IN EXCESS OF 6
FEET AND AN INCREASED THREAT OF RIP CURRENTS ALONG THE INDIANA
SHORELINE.

&&

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

KL

In the hours before

Local storm report, Jul 18, 8:23 PM CST, 37 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
923 PM CDT WED JUL 18 2007

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

0921 PM     TSTM WND DMG     WEST CHICAGO            41.89N 88.22W
07/18/2007                   DUPAGE             IL   EMERGENCY MNGR

            1 FOOT TREE DOWN.

&&

CMOTT

Local storm report, Jul 18, 8:24 PM CST, 36 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
924 PM CDT WED JUL 18 2007

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

0921 PM     TSTM WND DMG     WEST CHICAGO            41.89N 88.22W
07/18/2007                   DUPAGE             IL   EMERGENCY MNGR

            POWER LINES DOWN ON POWIS ROAD.

&&

CMOTT

Local storm report, Jul 18, 8:26 PM CST, 34 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
926 PM CDT WED JUL 18 2007

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

0921 PM     FLASH FLOOD      BENSENVILLE             41.96N 87.94W
07/18/2007                   DUPAGE             IL   EMERGENCY MNGR

            SPRING STREET 14 INCHES OF WATER. 6 TO 8 OF RAIN INCHES
            PER HOUR.

&&

CMOTT

Local storm report, Jul 18, 8:31 PM CST, 29 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
931 PM CDT WED JUL 18 2007

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

0920 PM     HEAVY RAIN       CHICAGO                 41.88N 87.63W
07/18/2007  M2.00 INCH       COOK               IL   PUBLIC

            2 INCHES OF RAIN FELL IN WRIGLEYVILLE.

&&

CMOTT

Local storm report, Jul 18, 8:33 PM CST, 27 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
933 PM CDT WED JUL 18 2007

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

0921 PM     TSTM WND DMG     LISLE                   41.79N 88.09W
07/18/2007                   DUPAGE             IL   TRAINED SPOTTER

            1 TO 2 INCH LIMBS DOWN OGDEN AND MAIN STREET.

&&

CMOTT

Local storm report, Jul 18, 8:35 PM CST, 25 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
935 PM CDT WED JUL 18 2007

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

0830 PM     HAIL             SCHAUMBURG              42.03N 88.08W
07/18/2007  E0.88 INCH       COOK               IL   PUBLIC

            NICKEL TO QUARTER SIZE HAIL.

&&

CMOTT

The radar

The Chicago radar (KLOT), 87 km away, was scanning. The volume nearest the first event began at 02:58 UTC.

Open the radar archive at this moment

Event by event

2 thunderstorm wind. Local standard time, as filed.

Thunderstorm Wind, Porter

When: July 18, 9:00 PM CST
Where: Porter County, Valparaiso
Measured: 55 kt (63 mph) estimated gust
Property damage: $5,000
Reported by: Law Enforcement
Coordinates: 41.470, -87.050

Trees and power lines blown down.

Thunderstorm Wind, Jasper

When: July 18, 10:23 PM CST
Where: Jasper County, Wheatfield
Measured: 50 kt (58 mph) estimated gust
Property damage: $5,000
Reported by: Law Enforcement
Coordinates: 41.200, -87.050

Two trees and powerlines blown down.

What these are

Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Indiana in 2007 Every state in 2007 This day in weather history Warnings in Indiana, July 2007

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 49703, 49704.