Tornadoes · United States · Illinois · 2015

EF1 tornado, Hartland, Illinois, April 9, 2015

This EF1 tornado ran 0.3 miles across McHenry County on April 9, 2015, touching down at 7:50 PM CDT and reaching 30 yards wide. It killed nobody.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mph

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. EF186 to 110 mphthis tornado

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. EF2111 to 135 mph

    Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

  4. EF3136 to 165 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. EF4166 to 200 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. EF5over 200 mph

    Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

  7. Unrated

    The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

The record

Rating
EF1
Date
April 9, 2015
Touchdown
7:50 PM CDT (00:50 UTC)
Lifted
7:51 PM CDT (00:51 UTC)
On the ground
1 minutes
Path length
0.3 miles (0.5 km)
Path width
30 yards (27 m)
Deaths
0
Injuries
0
County
McHenry County
Touchdown point
42.398, -88.531
Lift-off point
42.402, -88.527
Record number
1504091850-01

The damage survey

4 damage points were recorded along this path by NWS LOT, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 93 mph.

  • Softwoods snapped and uprooted, about 6-7 trees total affected. Most damage faced northeast, but uprooted tree in front of house pointed east. Antenna from roof of house blown off and tree falling onto house caused some roof damage.
  • Tornado touched down in field southwest of property on McGuire road

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

What the Weather Service recorded

Seven tornadoes were confirmed in north central Illinois in the NWS Chicago CWA. Six of the tornadoes formed from a single supercell. The atmosphere was ripe for severe weather due to highly anomalous moisture and instability for early April across the region. A strong low pressure system advanced into this favorable air mass. Combined with robust wind shear, this helped to trigger these potent storms. A long tracked violent tornado destroyed numerous homes and farmsteads along its path across north central Lee, eastern Ogle, northwest Dekalb, and southern Boone counties. This path included the far northwest side of Rochelle, Interstate-39, and a direct hit in the community of Fairdale where two fatalities occurred. This was the strongest tornado in the NWS Chicago CWA since the F5 tornado that struck Plainfield, IL on August 28th, 1990.

A brief tornado snapped and uprooted 6 to 7 trees at a property on McGuire Road southeast of Harvard. Minor tree damage occurred on the north side of the road before ending. Maximum winds were estimated to 90 mph. (Tornado 7 of 7).

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

9 minutes of warning. NWS LOT issued a tornado warning for this county at 00:41 UTC, 9 minutes before the tornado touched down, in force until 01:30 UTC.

The county was under a tornado watch, issued at 18:52 UTC and running to 03:37 UTC.

Issued (UTC)ExpiredProductOffice
18:52 UTC03:37 UTCTornado WatchLOT
23:56 UTC00:30 UTCTornado WarningLOT
00:16 UTC00:45 UTCTornado WarningLOT
00:19 UTC00:45 UTCTornado WarningLOT
00:21 UTC03:15 UTCFlood AdvisoryLOT
00:41 UTC01:30 UTCTornado WarningLOT
00:53 UTC01:30 UTCSevere Thunderstorm WarningLOT
01:05 UTC02:00 UTCSevere Thunderstorm WarningLOT
03:27 UTC09:00 UTCWind AdvisoryLOT

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The forecast that day

The Storm Prediction Center had this point in a Enhanced Risk, with a 0.10 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 20:00 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

What forecasters said that day

The local office's own words before the tornado touched down, 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 tornado touched down at Apr 9, 7:18 PM CDT, 32 minutes earlier.

Area forecast discussion, Apr 9, 7:18 PM CDT, 32 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
718 PM CDT THU APR 9 2015

.MESOSCALE DISCUSSION...536 PM CDT

CONTINUE TO MONITOR COLD FRONT WITH STRONG CONVECTION OCCURRING
NEAR THE MISSISSIPPI RIVER THIS HOUR. AHEAD OF THE FRONT WITHIN
THE WARM SECTOR THUNDERSTORMS HAVE STRUGGLED TO REACH THEIR FULL
POTENTIAL WITH MODEST MID LEVEL LAPSE RATES BEING ONE OF THE
PRIMARY LIMITING FACTORS. WIDELY SCATTERED ACTIVITY WILL CONTINUE
AHEAD OF THE FRONT THROUGH MID EVENING...THOUGH GIVEN TRENDS SO
FAR THE THREAT FOR SEVERE WEATHER APPEARS LOW AHEAD OF THE FRONT.
WITH CIRRUS SHIELD OVERSPREADING THE REGION AND LOWERING SUN
ANGLE...THERE ARE RENEWED CONCERNS REGARDING
INSTABILITY...ESPECIALLY AS WE GET CLOSER TO SUNSET THIS EVENING.
EXPECT MODERATE INSTABILITY TO PERSIST THROUGH 00Z THEN FOR A
DIMINISHING TREND OF MLCAPE THEREAFTER.

BY 00Z/7PM CDT...EXPECT THE LINE OF THUNDERSTORMS ASSOCIATED WITH
THE COLD FRONT WHICH WILL MAINTAIN A HIGHER SEVERE THREAT TO BE
NEAR THE I-39 CORRIDOR...AND ENTERING THE WESTERN SUBURBS OF
CHICAGO CLOSER TO 01Z/8PM CDT. LOW LEVEL CONVERGENCE ALONG THE
FRONT REMAINS STRONG AND DEEP LAYER SHEAR REMAINS SUFFICIENT TO
SUSTAIN AT LEAST SOME ORGANIZED/SEVERE THREAT THROUGH THE HEART OF
THE FORECAST AREA...THOUGH DIMINISHING MLCAPE MAY EVENTUALLY LOWER
THAT THREAT.

DEUBELBEISS

&&

.SHORT TERM...
400 AM CDT

TODAY AND TONIGHT...

DENSE FOG CONTINUES IN COOL/SATURATED AIR MASS WITH NORTHEAST
WINDS OFF THE LAKE THIS MORNING...WILL MAINTAIN DENSE FOG ADVISORY
ALONG THE LAKE AS ISSUED.

CLUSTERS OF THUNDERSTORMS WERE OCCURRING EARLY THIS MORNING
ACROSS THE MIDWEST...IN A REGION OF BROAD SOUTHWESTERLY WARM/MOIST
ADVECTION ATOP NEARLY STATIONARY FRONTAL BOUNDARY WHICH STRETCHES
FROM THE CENTRAL PLAINS INTO SOUTHERN IOWA...THEN EAST ACROSS
CENTRAL ILLINOIS AND INDIANA. THESE CLUSTERS OF STORMS WERE
GENERALLY TIED TO INDIVIDUAL MINOR-AMPLITUDE MID-LEVEL SHORT WAVE
FEATURES...AND ASSOCIATED LOCALIZED ENHANCED MOISTURE TRANSPORT
AND ASCENT. TO THE WEST...STRONG UPPER TROUGH WAS MOVING ONTO THE
PLAINS EAST OF THE ROCKIES...AND IS PROGGED TO APPROACH THE MID-
UPPER MISSISSIPPI VALLEY LATE THIS AFTERNOON AS A COMPACT AND
SOMEWHAT NEGATIVELY-TILTED ENERGETIC DISTURBANCE. SURFACE LOW
PRESSURE IN THE VICINITY OF SOUTHWEST KANSAS AT THIS HOUR WILL
DEEPEN AND LIFT TO SOUTHWESTERN WISCONSIN/FAR NORTHWEST IL PER
COMPLIMENTING GUIDANCE SOLUTIONS...WITH THE FRONT LIFTING NORTH AS
A WARM FRONT ACROSS THE FORECAST AREA. THIS PATTERN HAS ALL THE
EARMARKS OF BEING A WIDESPREAD SEVERE WEATHER PRODUCER ACROSS THE
AREA THIS AFTERNOON AND EVENING.

WITH THAT SAID...QUESTIONS REMAIN WITH RESPECT TO EVOLUTION OF
STORMS LATER TODAY...MAINLY DUE TO THE EXPECTATION THAT SEVERAL
CLUSTERS OF STORMS WILL CONTINUE TO DEVELOP/PROPAGATE ACROSS THE
AREA THROUGH MUCH OF THE DAY DUE TO PERSISTENT WARM/MOIST
ADVECTION AND ASCENT IN REGION OF STEEP MID-LEVEL LAPSE RATES
AHEAD OF THE DEEPENING TROUGH AND SURFACE LOW. CONVECTION ALLOWING
GUIDANCE (HRRR/NMM/ARW RUNS) DEPICT SEVERAL CLUSTERS DEVELOPING
AND LIFTING ACROSS THE AREA THROUGH THE MORNING AND MIDDAY
HOURS...AND REGIONAL RADAR MOSAIC SEEMS TO INDICATE THIS WILL BE
THE TREND AT LEAST THROUGH THIS MORNING. THUS WHILE SYNOPTIC
FEATURES WILL BE STRONG...MESOSCALE BOUNDARIES AND FORCING REMAIN
UNCLEAR AT THIS TIME. STILL...STRONG FORCING IN ADVANCE OF COLD
FRONT COUPLED WITH STRONG ASCENT ASSOCIATED WITH COMPACT WAVE
SHOULD BE CAPABLE OF GENERATING ORGANIZED SEVERE STORMS LATER THIS
AFTERNOON. 00Z NAM FORECAST SOUNDINGS INDICATE WARM SECTOR MLCAPES
AROUND 1500-2000 J/KG...WITH AMPLE DEEP AND LOW LEVEL SHEAR. SPC
NOTES SOME UNCERTAINTY WITH RESPECT TO STORM MODE...LINE SEGMENTS
AS OPPOSED TO DISCRETE CELLS...THOUGH SUPERCELLULAR
CHARACTERISTICS ARE LIKELY GIVEN THE ENVIRONMENT. DAMAGING WINDS
FROM LINES/LINE SEGMENTS LOOKS TO BE THE MOST WIDESPREAD
THREAT...THOUGH NORTHERN IL/SOUTHERN WI...WHERE WINDS WILL MOST
LIKELY BE BACKED MORE STRONGLY AHEAD OF THE LOW...WILL STILL HAVE
A REAL TORNADO POTENTIAL. STORMS WILL LIKELY EVOLVE UPSCALE INTO
SQUALL-LINE AS COLD FRONT MOVES ACROSS THE AREA EARLY THIS
EVENING...WITH THUNDERSTORM/SEVERE THREAT QUICKLY WINDING DOWN
BEFORE MIDNIGHT AFTER FROPA.

RATZER

&&

.LONG TERM...
257 PM CDT

FRIDAY THROUGH THURSDAY...

FOLLOWING A PERIOD OF VERY ACTIVE WEATHER...FOLLOWING THE PASSAGE OF
THE COLD FRONT LATE THURSDAY NIGHT...A PERIOD OF RELATIVE CALM WILL
SET UP FOR FRIDAY INTO SUNDAY AS A COOL...DRY HIGH PRESSURE AREA
BUILDS ACROSS THE AREA.  TEMPERATURES WILL DROP BACK TO CLOSER TO
SEASONAL HIGHS NORMAL LEVELS WITH HIGHS IN THE UPPER 50S TO AROUND
60F UNDER MOSTLY SUNNY SKIES.  AS THE HIGH WILL BE RIGHT OVER THE
AREA FRIDAY NIGHT INTO SATURDAY MORNING...LIGHT WINDS AND A DRY
AIRMASS WILL ALLOW FOR SOME ENHANCED RADIATIVE COOLING OVERNIGHT FOR
LOWS TO DROP BACK INTO THE MIDDLE TO UPPER 30S SATURDAY MORNING.
WITH THE HIGH BEGINNING TO BUILD OFF TO THE EAST THROUGH SATURDAY
NIGHT AND SUNDAY...A RETURN FLOW OF MOISTURE AND WARMER AIR WILL
KEEP THE COOLING TREND VERY BRIEF WITH TEMPS REBOUNDING BACK TO
AROUND 60F OVER MUCH OF THE CWA...WITH THE EXCEPTION OF THE
IMMEDIATE LAKEFRONT...WHICH SHOULD REMAIN COOLER AS A WEAK PRESSURE
GRADIENT AND DIFFERENTIAL HEATING BETWEEN THE COOL LAKE WATER AND
WARMER LAKE SHOULD ALLOW A LAKE BREEZE TO DEVELOP.  HIGHS ON
SATURDAY ALONG THE LAKE FRONT TOPPING OUT IN THE MIDDLE 50S.
INCREASING SOUTHERLY FLOW ON THE WESTERN PERIPHERY OF THE HIGH
MOVING OFF TO THE EAST WILL LIKELY PREVENT A LAKE BREEZE FROM
DEVELOPING.

FOR SUNDAY...A NORTHERN STREAM SHORT WAVE MOVING OUT OF THE NRN
ROCKIES SHOULD BEGIN TO PHASE WITH A SOUTHERN STREAM SHORTWAVE
LIFTING INTO THE MIDDLE MISSISSIPPI VALLEY.  THIS PHASING SHOULD
RESULT IN AN AMPLIFYING LONG WAVE TROUGH OVER THE MIDDLE AND UPPER
MISSISSIPPI VALLEY AND BRINGING THE NEXT CHANCE OF PCPN TO THE
REGION.  THE LONGER RANGE GUIDANCE...IN GENERAL...AGREE ON THE
SCENARIO...BUT DIFFERENCES IN THE TIMING OF THE INDIVIDUAL SHORTWAVE
AND THE DEGREE OF PHASING AND THE RESULTANT STRENGTH OF THE LONG
WAVE TROUGH LEAD TO A RELATIVELY LOW CONFIDENCE FORECAST FOR THE
LATTER PORTIONS OF THE EXTENDED FORECAST PERIOD.  CURRENTLY FEEL
THAT A COLD FRONT MOVING ACROSS THE AREA SUNDAY INTO SUNDAY NIGHT
AND THEN SHUTTING OFF BY MONDAY MORNING AS ANOTHER HIGH PRESSURE
SYSTEM MOVES ACROSS THE AREA.  WHILE THERE IS MODERATE TO HIGH
CONFIDENCE IN A PERIOD OF PCPN SUNDAY AND SUNDAY NIGHT...START AND
END TIMES REMAIN UNCERTAIN AS WELL AS THE CHANCES FOR THUNDERSTORMS
WITH THE PCPN AND WILL LIKELY BE HIGHLY DEPENDENT ON THE SPEED OF AN
ASSOCIATED COLD FRONT MOVING THROUGH THE AREA.  FOR THE LATTER
PORTIONS OF THE FORECAST PERIOD...FROM TUESDAY THROUGH
THURSDAY...THERE COULD BE ANOTHER PERIOD OF UNSETTLED WEATHER AS THE
UPPER LEVEL FLOW PATTERN MAINTAINS A HIGH AMPLITUDE...QUICKLY
PROGRESSIVE PATTERN.  THE GFS/ECMWF ARE ACTUALLY SHOWING BETTER
CONSISTENCY FOR THE END OF THE LONGER TERM FORECAST PERIOD THAN
EARLIER...WITH ANOTHER LONG WAVE TROUGH DEVELOPING OVER THE CNTRL
PLAINS.  THE ECMWF IS TRENDING A BIT STRONGER AND DEVELOPING MORE OF
A NEGATIVE TILT TO THE TROUGH AND A CLOSED UPPER LOW BY WEDNESDAY
NIGHT...THE GFS IS REMARKABLY SIMILAR...BUT ABOUT 24 HOURS SLOWER IN
DEVELOPING THE NEGATIVE TILT UPPER TROUGH AND CLOSED UPPER LOW.
SHOULD THIS SCENARIO PAN OUT...THE MIDDLE OF NEXT WEAK COULD BE RIPE
FOR ANOTHER PERIOD OF ACTIVE WEATHER.

KREIN

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* SCATTERED STORMS EXPECTED THIS AFTN...WITH THE FINAL ROUND OF
  STORMS MOVING THROUGH ARND 2Z-4Z. SOME OF THESE STORMS COULD BE
  SEVERE WITH GUSTY WINDS.

* GUSTY SSW WINDS WITH GUSTS ARND 25 KT.

* IFR VSBY EXPECTED WITH TSRA.

* IFR CIGS BEHIND THE LINE OF STORMS OVER NIGHT...BECOMING MVFR

* GUSTY WINDS BCMG SW TO W ARND MIDNIGHT WITH MAX GUSTS 30-35 KT.

KMD

//DISCUSSION...UPDATED 00Z...

STRONGEST THUNDERSTORM ACTIVITY IS IN THE NORTHWEST CORNER OF THE
COUNTY WARNING AREA THIS EVENING...WITH A BROKEN LINE OF STORMS
EXTENDING SOUTH THROUGH WESTERN ILLINOIS EARLY THIS EVENING.
ADDITIONALLY...SOME ISOLATED THUNDESTORMS EXIST OUT AHEAD OF THE
MAIN LINE. WHILE THE LINE FARTHER WEST IS NOT COMPLETELY FILLED IN
YET...AS THE COLD FRONT MAKES EASTWARD PROGRESS...EXPECT THIS LINE
TO BECOME FILLED IN...REACHING THE CHICAGOLAND TERMINALS AROUND
145-2Z. EXPECT SCATTERED THUNDERSTORMS OUT AHEAD OF THIS MAIN
LINE. EXPECT HAIL...STRONG WINDS...AND HEAVY RAIN WITH THESE
STORMS WHEN THEY DO FILL IN. CONFIDENCE IS STILL MEDIUM ON THE
TIMING AND COVERAGE.

AFTER THESE STORMS CLEAR...EXPECT GUSTY WSW WINDS WITH CIGS
LOWERING TO MVFR AND POSSIBLY IFR. LIFTING IS EXPECTED FRIDAY
MORNING BUT CONTINUED GUSTY WINDS.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH CONFIDENCE IN SCATTERED STORMS EARLY THIS EVENING FOLLOWED
  BY A SEGMENT OR SEMI-BROKEN LINE OF STORMS LATER THIS EVENING.
  MEDIUM CONFIDENCE IN COVERAGE THIS EVENING AND TIMING.

* MEDIUM CONFIDENCE IN WIND DIRECTION BEHIND THE SCATTERED STORMS.
  WINDS COULD BE CHAOTIC FOR A BRIEF PERIOD OF TIME.

* HIGH CONFIDENCE IN REDUCED VSBY UNDER STORMS...MEDIUM-LOW
  CONFIDENCE IN CIG HEIGHTS.

* HIGH CONFIDENCE IN LOWER CIGS TONIGHT...LOW ON SPECIFIC HEIGHTS
  AND HOW LONG IFR WILL LAST.

* MEDIUM CONFIDENCE IN WIND GUSTS OVERNIGHT AND TOMORROW...GUSTS
  COULD BE HIGHER.

KMD

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED
00Z...

* SATURDAY...DRY/VFR. SOUTHWEST WINDS. LAKE BREEZE POSSIBLE.
* SUNDAY...DRY/VFR. GUSTY SOUTH WINDS.
* MONDAY...DRY/VFR. EAST WINDS.
* TUESDAY...CHANCE OF SHRA/TSRA. MVFR POSSIBLE. SOUTH WINDS.
* WEDNESDAY...CHANCE OF SHRA. SOUTH WINDS.

&&

.MARINE...
315 PM CDT

CONDITIONS OVER LAKE MICHIGAN ARE DETERIORATING RAPIDLY
TODAY...FIRST WITH WAVES OF THUNDERSTORMS CROSSING THE SOUTHERN
PORTIONS OF THE LAKE AS A WARM FRONT LIFTS NORTHWARD.  AS OF 3PM
CDT...THE FRONT HAD MOVED UP TO THE CENTER OF THE LAKE AND SHOULD
CONTINUE TO LIFT NORTHWARD AS DEEPENING LOW PRESSURE OVER EASTERN
IOWA CONTINUES TO DEEPEN AND TRACKS INTO SOUTHERN WISCONSIN BY EARLY
THIS EVENING.  BY THIS POINT...THE SOUTHERLY FLOW WILL REACH ALMOST
TO THE NORTH END OF THE LAKE...BUT WITH STRONG PRESSURE FALLS AND A
STRENGTHENING PRESSURE GRADIENT OVER THE LAKE AS THE SFC LOW
APPROACHES...WINDS OVER THE SRN PORTIONS OF THE LAKE SHOULD INCREASE
TO GALE FORCE FOR THE NEARSHORE WATERS AND THE SOUTH HALF OF THE
LAKE.  THUNDERSTORMS WILL ALSO CONTINUE TO BE A CONCERN INTO THE
EVENING AS WELL.  THE SFC LOW IS EXPECTED TO TRACK ACROSS THE CNTRL
PORTIONS OF THE LAKE LATE THIS EVENING...WITH WINDS QUICKLY SHIFTING
TO WLY-NWLY.  A STRONG NORTHERLY GRADIENT BEHIND THE EXITING
LOW...INCREASING COLD ADVECTION ASSOCIATED WITH A COOL HIGH PRESSURE
SYSTEM DROPPING INTO THE NRN PLAINS AND STRONG PRESSURE RISES AS A
RESULT OF THE COMBINATION OF THE EXITING LOW AND APPROACHING
HIGH...SHOULD ALL COMBINE TO BRING SHORT PERIOD OF WEST TO NWLY
GALES TO THE LAKE INTO FRIDAY AFTERNOON.  THE APPROACHING HIGH
SHOULD BEGIN TO OVERSPREAD THE WESTERN GREAT LAKES BY FRIDAY
AFTERNOON...ALLOWING WINDS OVER THE LAKE TO DROP OFF RELATIVELY
QUICKLY.  FOR THE WEEKEND AND INTO EARLY NEXT WEEK...CONDITIONS OVER
THE LAKE SHOULD BE RELATIVELY QUIET.  ANOTHER COLD FRONT IS EXPECTED
TO SWEEP ACROSS THE LAKE SUNDAY NIGHT OR MONDAY...BUT THIS SHOULD BE
A LESS DYNAMIC SYSTEM...AND WINDS SHOULD NOT GET AS STRONG AS WITH
THE SYSTEM APPROACHING THE LAKE AT THE CURRENT TIME.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
     LMZ779 UNTIL 1 PM FRIDAY.

&&

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
Hazardous weather outlook, Apr 9, 3:28 PM CDT, 4 hours 22 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
328 PM CDT THU APR 9 2015

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
102030-
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-
328 PM CDT THU APR 9 2015

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

  WEATHER HAZARDS EXPECTED:

  THUNDERSTORMS...SOME MAY BE SEVERE AND PRODUCE:

   LOCALLY HEAVY RAINFALL RESULTING IN LOCALIZED FLOODING.
   HAIL UP TO THE SIZE OF QUARTERS
   DAMAGING WINDS UP TO 70 MPH.
   FREQUENT CLOUD TO GROUND LIGHTNING.
   AND POSSIBLY AN ISOLATED TORNADO.

  AREAS AFFECTED AND TIMING:

   A COLD FRONT WILL SWEEP WEST TO EAST ACROSS NORTHERN ILLINOIS
 AND NORTHWEST INDIANA LATE THIS AFTERNOON THROUGH THE EVENING.

  DISCUSSION:

A COLD FRONT WILL SWEEP ACROSS THE REGION THIS EVENING BRINGING
PRIMARILY A THREAT FOR STRONG AND DAMAGING WINDS ALONG WITH A
CONCERN FOR A TORNADO. AHEAD OF THE MAIN LINE OF THUNDERSTORMS...
SCATTERED THUNDERSTORMS ARE POSSIBLE LATE THIS AFTERNOON INTO THE
EARLY EVENING. THE SEVERE WEATHER THREAT SHOULD DIMINISH QUICKLY
BEHIND THE FRONT. IN ADDITION TO THE SEVERE WEATHER THREAT...SOME
AREAS HAVE ALREADY SEEN HEAVY RAIN TODAY WITH SOILS SATURATED.
ADDITIONAL HEAVY RAIN WILL QUICKLY BE CONVERTED TO RUNOFF WITH A
CONCERN FOR AT LEAST LOCALIZED FLOODING.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

THERE IS A CHANCE OF THUNDERSTORMS LATE SUNDAY AFTERNOON INTO
SUNDAY NIGHT...AND AGAIN TUESDAY NIGHT THROUGH THURSDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NECESSARY THROUGH TONIGHT.

&&

LMZ740>745-102030-
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-
328 PM CDT THU APR 9 2015

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

SCATTERED THUNDERSTORMS ARE LIKELY THROUGH LATE THIS EVENING.
SOME THUNDERSTORMS MAY BE SEVERE LATE THIS AFTERNOON AND EARLY
THIS EVENING.

GALE FORCE WINDS ARE EXPECTED LATE THIS EVENING AND OVERNIGHT.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

GALE FORCE WINDS ARE LIKELY THROUGH MIDDAY FRIDAY...WITH
WINDS AND WAVES REMAINING HAZARDOUS FOR SMALL CRAFT INTO FRIDAY
EVENING.

THERE IS A CHANCE OF THUNDERSTORMS SUNDAY NIGHT...AND AGAIN
TUESDAY NIGHT THROUGH THURSDAY.

&&

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-102030-
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-
328 PM CDT THU APR 9 2015

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

THUNDERSTORMS ARE LIKELY ACROSS MAINLY THE SOUTH HALF OF THE LAKE
INTO THIS EVENING. SOME STORMS COULD BE SEVERE.

GALE FORCE WINDS ARE EXPECTED TONIGHT OVER THE SOUTHERN HALF OF
THE LAKE.

GALE FORCE WINDS ARE EXPECTED OVER THE NORTHERN HALF OF THE LAKE
AFTER MIDNIGHT TONIGHT.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

GALE FORCE WINDS ARE LIKELY THROUGH MIDDAY THURSDAY ON THE
SOUTHERN HALF OF THE LAKE.

GALE FORCE WINDS ARE LIKELY THROUGH LATE THURSDAY AFTERNOON ON THE
NORTHERN HALF OF THE LAKE.

THERE IS A CHANCE OF THUNDERSTORMS ON SOUTHERN LAKE MICHIGAN
SUNDAY NIGHT...AND AGAIN TUESDAY NIGHT THROUGH THURSDAY.

&&

BMD/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

Local storm report, Apr 9, 7:19 PM CDT, 31 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
719 PM CDT THU APR 09 2015

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

0658 PM     HAIL             CRYSTAL LAKE            42.23N 88.33W
04/09/2015  E0.88 INCH       MCHENRY            IL   TRAINED SPOTTER

0710 PM     TORNADO          4 W KIRKLAND            42.09N 88.93W
04/09/2015                   DE KALB            IL   TRAINED SPOTTER

            TOUCHDOWN BETWEEN MONROE CENTER AND FAIRDALE NEAR OGLE
            DEKALB COUNTY LINE. DAMAGE REPORTED.

&&

B
Local storm report, Apr 9, 7:28 PM CDT, 22 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
728 PM CDT THU APR 09 2015

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

0725 PM     HAIL             CHERRY VALLEY           42.24N 88.96W
04/09/2015  E1.75 INCH       WINNEBAGO          IL   TRAINED SPOTTER

            AT US20 AND NELL RD.

&&

B
Local storm report, Apr 9, 7:32 PM CDT, 18 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
732 PM CDT THU APR 09 2015

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

0715 PM     TORNADO          4 NW KIRKLAND           42.13N 88.91W
04/09/2015                   DE KALB            IL   TRAINED SPOTTER

            TIME BASED ON RADAR. DAMAGE TO HOUSES AND LARGE TREES
            UPROOTED.

&&

KBIRK
Local storm report, Apr 9, 7:45 PM CDT, 5 minutes before
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
745 PM CDT THU APR 09 2015

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

1042 AM     LIGHTNING        MOUNT PROSPECT          42.07N 87.94W
04/09/2015                   COOK               IL   TRAINED SPOTTER

            LIGHTNING STRIKE 200 E BLOCK PROSPECT AVE. STRUCTURE
            FIRE.

0623 PM     HAIL             2 SE DIXON              41.83N 89.45W
04/09/2015  M1.00 INCH       LEE                IL   AMATEUR RADIO

0628 PM     HAIL             2 SE DIXON              41.83N 89.45W
04/09/2015  M1.75 INCH       LEE                IL   AMATEUR RADIO

            HAIL NOW TO GOLF BALL SIZE.

0629 PM     FUNNEL CLOUD     2 SE ROCKFORD AIRPORT   42.18N 89.07W
04/09/2015                   WINNEBAGO          IL   TRAINED SPOTTER

            REPORTED BY SPOTTER AND THE OBSERVER AT THE AIRPORT.
            LOCATION ESTIMATED.

0632 PM     HAIL             1 N FRANKLIN GROVE      41.86N 89.30W
04/09/2015  M1.75 INCH       LEE                IL   TRAINED SPOTTER

            DAYSDILLE ROAD AND NAYLOR

0636 PM     HAIL             1 N FRANKLIN GROVE      41.86N 89.30W
04/09/2015  M1.75 INCH       LEE                IL   TRAINED SPOTTER

0638 PM     HAIL             5 N FRANKLIN GROVE      41.91N 89.30W
04/09/2015  E1.75 INCH       OGLE               IL   TRAINED SPOTTER

0640 PM     TORNADO          1 E CHERRY VALLEY       42.24N 88.94W
04/09/2015                   WINNEBAGO          IL   LAW ENFORCEMENT

            RT 20 AND WHEELER ROAD. PUBLIC REPORT RELAYED VIA BOONE
            COUNTY SHERIFF.

0640 PM     TORNADO          2 NE FRANKLIN GROVE     41.86N 89.27W
04/09/2015                   LEE                IL   TRAINED SPOTTER

            VIEWED FROM I-88. DEBRIS SEEN.

0643 PM     TORNADO          CHERRY VALLEY           42.24N 88.96W
04/09/2015                   WINNEBAGO          IL   TRAINED SPOTTER

            CONFIRMED.

0643 PM     TORNADO          5 SE ASHTON             41.82N 89.15W
04/09/2015                   LEE                IL   TRAINED SPOTTER

            TORNARDO REPORTED DOING DAMAGE NEAR ASHTON. RELAYED BY
            DVN

0645 PM     HAIL             2 E MOUNT MORRIS        42.05N 89.39W
04/09/2015  M1.75 INCH       OGLE               IL   TRAINED SPOTTER

0645 PM     HAIL             HOFFMAN ESTATES         42.06N 88.14W
04/09/2015  E1.00 INCH       COOK               IL   TRAINED SPOTTER

            AT INTERSECTION OF WESTBURY AND BAYSIDE. HEAVY RAIN.

0650 PM     HAIL             HUNTLEY                 42.17N 88.42W
04/09/2015  E1.00 INCH       MCHENRY            IL   TRAINED SPOTTER

            AT INTERSECTION OF DUNDEE RD AND HALIGHUS.

0656 PM     HAIL             LAKE IN THE HILLS       42.19N 88.32W
04/09/2015  E0.88 INCH       MCHENRY            IL   TRAINED SPOTTER

            PEA TO NICKEL SIZE HAIL

0658 PM     HAIL             CRYSTAL LAKE            42.23N 88.33W
04/09/2015  E0.88 INCH       MCHENRY            IL   TRAINED SPOTTER

0702 PM     TORNADO          5 N HILLCREST           42.02N 89.07W
04/09/2015                   OGLE               IL   TRAINED SPOTTER

            SEVERAL REPORTS OF A LARGE WEDGE TORNADO ON THE GROUND.

0710 PM     TORNADO          4 W KIRKLAND            42.09N 88.93W
04/09/2015                   DE KALB            IL   TRAINED SPOTTER

            TOUCHDOWN BETWEEN MONROE CENTER AND FAIRDALE NEAR OGLE
            DEKALB COUNTY LINE. DAMAGE REPORTED.

0715 PM     TORNADO          4 NW KIRKLAND           42.13N 88.91W
04/09/2015                   DE KALB            IL   TRAINED SPOTTER

            TIME BASED ON RADAR. DAMAGE TO HOUSES AND LARGE TREES
            UPROOTED.

0725 PM     HAIL             CHERRY VALLEY           42.24N 88.96W
04/09/2015  E1.75 INCH       WINNEBAGO          IL   TRAINED SPOTTER

            AT US20 AND NELL RD.

&&

B
Local storm report, Apr 9, 7:48 PM CDT, 2 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
748 PM CDT THU APR 09 2015

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

0740 PM     TORNADO          1 W MARENGO             42.25N 88.62W
04/09/2015                   MCHENRY            IL   EMERGENCY MNGR

            ROUTE 20 AND JOHNSON ROAD. BETWEEN MARENGO AND GARDEN
            PRAIRIE

&&

DONOFRIO
Local storm report, Apr 9, 7:50 PM CDT, 0 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
750 PM CDT THU APR 09 2015

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

0640 PM     TORNADO          ASHTON                  41.87N 89.22W
04/09/2015                   LEE                IL   TRAINED SPOTTER

            REPORT OF DAMAGE AND INJURIES AT THE KRAFT FOOD WAREHOUSE
            NEAR ASHTON. TIME ESTIMATED FROM RADAR.

&&

KBIRK

The air that afternoon

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Davenport, (KDVN), 00:00Z

0.8 hours before the tornado, 184 km from the path. April 10, 2015.

Skew-T log-pSkew-T log-p diagram, Davenport, at 00:00Z on 2015-04-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 338 joules per kilogram, CIN -52, lifted condensation level 1114 meters above ground. Wind barbs in knots down the right edge.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. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Davenport, at 00:00Z on 2015-04-10The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 104 square meters per square second, 0 to 6 km bulk shear 66 knots.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. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
338 J/kg
Mixed-layer CIN
-52 J/kg
Surface CAPE
375 J/kg
Mixed-layer LCL
1114 m above ground
0-6 km bulk shear
66 kt
0-1 km bulk shear
53 kt
0-1 km storm-relative helicity
104 m²/s²
0-3 km storm-relative helicity
122 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.4
0-3 km lapse rate
5.5 K/km

Open this sounding in Storm Lab

Davenport, (KDVN), 12:00Z

11.2 hours after it, 184 km from the path. April 10, 2015.

Skew-T log-pSkew-T log-p diagram, Davenport, at 12:00Z on 2015-04-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -112079, lifted condensation level 1240 meters above ground. Wind barbs in knots down the right edge.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. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Davenport, at 12:00Z on 2015-04-10The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity -227 square meters per square second, 0 to 6 km bulk shear 74 knots.1939587897117Sfc1 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. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
-112079 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1240 m above ground
0-6 km bulk shear
74 kt
0-1 km bulk shear
30 kt
0-1 km storm-relative helicity
-227 m²/s²
0-3 km storm-relative helicity
-185 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.6 K/km

Open this sounding in Storm Lab

The surface observations

Burlington (BUU), 37 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
22:55 UTC5150.54110° 6 kt1000
23:15 UTC5151120° 4 kt999.7-RA
23:35 UTC515160° 3 kt999.3-RA
23:55 UTC5150.54120° 6 kt998.3BR
00:15 UTC5151100° 5 kt998.3RA
00:35 UTC49.2849140° 3 kt999.3+RA
00:55 UTC53.4253.420° 0 kt998.3-SN
01:15 UTC52.3452.1670° 6 kt997-RA
01:35 UTC52.3452.1610° 8 kt998-RA
01:55 UTC49.2849100° 4 kt997-RA
02:15 UTC5151170° 4 kt996.3BR
02:35 UTC52.8852.88170° 5 kt995.9

From the Iowa Environmental Mesonet's archive of airport observations.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
23:29 UTCFUNNEL CLOUD2 Se Rockford AirportWinnebago, ILREPORTED BY SPOTTER AND THE OBSERVER AT THE AIRPORT. LOCATION ESTIMATED.
23:37 UTCTORNADO3 S Cherry ValleyWinnebago, ILRATING: EF-0 ESTIMATED PEAK WIND: 65 MPH PATH LENGTH /STATUTE/: 2.8 MILES PATH WIDTH /MAXIMUM/: 25 YARDS START DATE: APRIL 09 2015 START TIME:6:37 PM CDT START LOCATION: 2.9 MILES S CHERRY VALLEY START LAT/LON: 42.1926/-
23:40 UTCTORNADO1 E Cherry ValleyWinnebago, ILRT 20 AND WHEELER ROAD. PUBLIC REPORT RELAYED VIA BOONE COUNTY SHERIFF.
23:43 UTCTORNADOCherry ValleyWinnebago, ILCONFIRMED.
23:45 UTCHAIL 1Hoffman EstatesCook, ILAT INTERSECTION OF WESTBURY AND BAYSIDE. HEAVY RAIN.
23:50 UTCHAIL 1HuntleyMchenry, ILAT INTERSECTION OF DUNDEE RD AND HALIGHUS.
23:56 UTCHAIL 0.88Lake In The HillsMchenry, ILPEA TO NICKEL SIZE HAIL
23:58 UTCHAIL 0.88Crystal LakeMchenry, IL
00:04 UTCHAIL 0.75CapronBoone, IL
00:05 UTCTORNADO11 Nne RochelleOgle, ILRATING: EF-0 ESTIMATED PEAK WIND: 65 MPH PATH LENGTH /STATUTE/: 1.9 MILES PATH WIDTH /MAXIMUM/: 100 YARDS START DATE:APRIL 09 2015 START TIME:7:05 PM CDT START LOCATION:2.9 MILES E LINDENWOOD START LAT/LON: 42.0583/-88.9
00:10 UTCTORNADO4 W KirklandDe Kalb, ILTOUCHDOWN BETWEEN MONROE CENTER AND FAIRDALE NEAR OGLE DEKALB COUNTY LINE. DAMAGE REPORTED.
00:15 UTCTORNADO3 Nnw KirklandDe Kalb, ILRATING: EF-1 ESTIMATED PEAK WIND: 110 MPH PATH LENGTH /STATUTE/: 4.0 MILES PATH WIDTH /MAXIMUM/: 100 YARDS START DATE: APRIL 09 2015 START TIME: 7:15 PM CDT START LOCATION: 3.1 MILES NW KIRKLAND START LAT/LON: 42.1334/-8
00:15 UTCTORNADO4 Nw KirklandDe Kalb, ILTIME BASED ON RADAR. DAMAGE TO HOUSES AND LARGE TREES UPROOTED.
00:24 UTCTORNADO3 S BelvidereBoone, ILRATING: EF-0 ESTIMATED PEAK WIND: 85 MPH PATH LENGTH /STATUTE/: 0.4 MILES PATH WIDTH /MAXIMUM/: 30 YARDS START DATE: APRIL 09 2015 START TIME:7:24 PM CDT START LOCATION: 3.8 MILES S BELVIDERE START LAT/LON: 42.2073/-88.8
00:25 UTCHAIL 1.75Cherry ValleyWinnebago, ILAT US20 AND NELL RD.
00:25 UTCTORNADO6 Se BelvidereBoone, ILRATING: EF-1 ESTIMATED PEAK WIND: 110 MPH PATH LENGTH /STATUTE/: 3.9 MILES PATH WIDTH /MAXIMUM/: 50 YARDS START DATE: APRIL 09 2015 START TIME:7:25 PM CDT START LOCATION: 6 MILES SE BELVIDERE START LAT/LON: 42.2442/-88.7
00:34 UTCTORNADOBelvidereBoone, ILPOSSIBLE TORNADO DAMAGE NEAR BELVIDERE. TIME BASED ON RADAR.
00:35 UTCTORNADO1 S HarvardMchenry, ILIL23 AND STREIT ST. DEBRIS - SHEET METAL AND SIDING.
00:35 UTCTORNADO1 S HarvardMchenry, ILIL23 AND STREIT ST. DEBRIS-SHEET METAL AND SIDING.
00:40 UTCTORNADO1 W MarengoMchenry, ILROUTE 20 AND JOHNSON ROAD. BETWEEN MARENGO AND GARDEN PRAIRIE
00:50 UTCTORNADO5 Ese HarvardMchenry, ILRATING: EF-1 ESTIMATED PEAK WIND: 90 MPH PATH LENGTH /STATUTE/: 0.3 MILES PATH WIDTH /MAXIMUM/: 30 YARDS START DATE: APRIL 09 2015 START TIME: 7:50 PM CDT START LOCATION: 4.4 MILES EAST SOUTHEAST OF HARVARD START LAT/LON
01:08 UTCHAIL 11 Ne UnionMchenry, ILALONG IL-176.
01:15 UTCHAIL 1MchenryMchenry, ILBULL VALLEY RD AND GREEN STREET.
01:15 UTCHAIL 1WoodstockMchenry, ILDIME TO QUARTER SIZE HAIL
01:17 UTCHAIL 1WoodstockMchenry, ILTROOP ST AND KISHWAUKEE.
01:27 UTCHAIL 1MchenryMchenry, ILDARKMOR AND CRYSTAL LAKE RD.
01:28 UTCHAIL 1WoodstockMchenry, ILFLEMING ROAD AND BULL VALLEY ROAD.
02:30 UTCFLOOD1 W Beach ParkLake, IL0.89 IN LAST 40 MINUTES. STORM TOTAL FROM LAST NIGHT TO TONIGHT IS 3.10 INCHES. SOME ROAD WAYS FLOODED AND ROAD SHOULDERS WASHED OUT.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2015 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

The other tornadoes of April 9, 2015

18 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 91:32 PM CDTEF0Peoria, IL0.110
April 95:04 PM CDTEF1Scott, IA22.4100$20,000
April 96:22 PM EDTEF0Hillsdale, MI0.670
April 95:40 PM CDTEF1Clinton, IA to IL12.575
April 96:02 PM CDTEF1Carroll, IL8.350
April 96:37 PM CDTEF0Boone, IL2.825
April 96:38 PM CDTEF2Cherokee, TX1.8340$300,000
April 96:39 PM CDTEF4Rochelle–Fairdale tornado, IL30.1700211$19 million
April 97:05 PM CDTEF0Ogle, IL1.9100
April 97:10 PM CDTEF1Gregg, TX1.3335$1.0 million
April 97:15 PM CDTEF1Boone, IL4.0100$80,000
April 97:20 PM CDTEF1Harrison, TX4.5760$300,000
April 97:24 PM CDTEF0Boone, IL0.430$20,000
April 97:25 PM CDTEF1Boone, IL3.950$150,000
April 97:47 PM CDTEF0Christian, IL0.110
April 99:08 PM CDTEF0Custer, OK0.230
April 99:16 PM CDTEF0Cape Girardeau, MO1.8150$6,000
April 99:31 PM CDTEF0Cape Girardeau, MO1.7130$60,000

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.