Alert archive / Illinois / Flash Flood Warnings in 2011

Flash Flood Warning 20, NWS Chicago, IL

July 23, 2011Cook County, DuPage County, Illinois; Lake County, Indiana

NWS Chicago, IL issued this flash flood warning at Jul 23, 2011, 1:19 AM CDT for Cook County, DuPage County, Illinois; Lake County, Indiana. It was in force for 6 hr. 16 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 23, 2011, 1:19 AM CDT (06:19 UTC)
Expired: Jul 23, 2011, 7:30 AM CDT
In force: 6 hr
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Flood severity: None

Counties Cook County, IL, DuPage County, IL, Lake County, IN

The radar

The Chicago radar (KLOT), 46 km from the middle of the area, began a volume at 06:21 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.

What was reported inside it

Time	Report	Where	Remark
Jul 23, 1:51 AM CDT	HEAVY RAIN 2.34	Ohare Airport, IL	MEASURED RAINFALL OF 2.34 INCHES BETWEEN 1251 AM AND 151 AM OBSERVATIONS.
Jul 23, 2:00 AM CDT	HEAVY RAIN 1.84	2 Nw Melrose Park, IL	MEASURED RAINFALL OF 1.84 INCHES BETWEEN 1 AM AND 2 AM.
Jul 23, 2:20 AM CDT	FLASH FLOOD	1 N Chicago, IL	CARS STUCK ON CHICAGO AVENUE DUE TO FLOODING.
Jul 23, 2:20 AM CDT	FLASH FLOOD	2 N Chicago, IL	UNDERPASS FROM NORTHBOUND MICHIGAN AVENUE TO LAKE SHORE DRIVE FLOODED.
Jul 23, 2:20 AM CDT	FLASH FLOOD	2 Nw Chicago, IL	CITY OF CHICAGO OEMC REPORTS OHIO STREET RAMP TO I-94 KENNEDY EXPRESSWAY CLOSED DUE TO FLOODING.
Jul 23, 2:45 AM CDT	HEAVY RAIN 3.2	Sse Carol Stream, IL	2.36 INCHES IN THE PAST 40 MINUTES.
Jul 23, 2:51 AM CDT	HEAVY RAIN 5.53	Ohare Airport, IL	MEASURED RAINFALL OF 5.53 INCHES BETWEEN 1251 AM AND 251 AM OBSERVATIONS.
Jul 23, 2:52 AM CDT	HEAVY RAIN 5.53	Ohare Airport, IL	MEASURED RAINFALL OF 5.53 INCHES BETWEEN 1251 AM AND 252 AM OBSERVATIONS.
Jul 23, 3:10 AM CDT	FLASH FLOOD	Chicago, IL	MAJOR FLOODING FORCED CLOSURE OF ALL LANES OF I-94... THE DAN RYAN EXPRESSWAY...IN BOTH DIRECTIONS AT 87TH STREET AND NORTHBOUND AT 67TH STREET.
Jul 23, 3:23 AM CDT	HEAVY RAIN 2.84	Glen Ellyn, IL	1 HOUR OF RAIN BETWEEN 223 AM AND 323 AM CDT. NORTH GLEN ELLYN.
Jul 23, 6:09 AM CDT	HEAVY RAIN 0.75	Hammond, IN	RAINFALL OVERNIGHT.
Jul 23, 6:30 AM CDT	HEAVY RAIN 2.7	3 Sw Midway Airport, IL	24 HOUR TOTAL. 1.90 INCHES FELL SINCE MIDNIGHT.
Jul 23, 7:00 AM CDT	HEAVY RAIN 2.79	Westmont, IL	24-HOUR TOTAL. 2.29 INCHES FELL OVERNIGHT.
Jul 23, 7:00 AM CDT	HEAVY RAIN 8.2	Ohare Airport, IL	24-HOUR TOTAL. 6.91 INCHES BETWEEN 100 AM AND 700 AM.
Jul 23, 7:20 AM CDT	HEAVY RAIN 4.6	Melrose Park, IL	TOTAL SINCE MIDNIGHT MEASURED BY MELROSE PARK PUBLIC SAFETY.
Jul 23, 7:25 AM CDT	HEAVY RAIN 2.95	Lyons, IL	24-HOUR TOTAL. 2.3 INCHES OVERNIGHT.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched 4 storm reports to this flash flood warning; the first came 61 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 6.3 hours before the alert went out and 195 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 4513 J/kg
Mixed-layer CIN: -25 J/kg
Mixed-layer LCL: 1153 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 88 m²/s²
0-3 km storm-relative helicity: 102 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 5.7

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

622 
WGUS53 KLOT 230619
FFWLOT
ILC031-043-INC089-231230-
/O.NEW.KLOT.FF.W.0020.110723T0619Z-110723T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
119 AM CDT SAT JUL 23 2011

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  COOK COUNTY IN NORTHEAST ILLINOIS...
  NORTHEASTERN DUPAGE COUNTY IN NORTHEAST ILLINOIS...
  NORTHERN LAKE COUNTY IN NORTHWEST INDIANA...

* UNTIL 730 AM CDT

* AT 118 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  SLOW MOVING THUNDERSTORMS PRODUCING TORRENTIAL RAINFALL...MOVING 
  SOUTHEAST ACROSS EASTERN DUPAGE AND CENTRAL COOK COUNTIES. 
  RAINFALL RATES UP TO 3 INCHES PER HOUR ARE POSSIBLE FROM THESE     
  THUNDERSTORMS. THIS AMOUNT OF RAINFALL CAN QUICKLY CAUSE FLASH     
  FLOODING...ESPECIALLY IN URBAN AREAS.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. VISIBILITIES WILL ALSO BE REDUCED TO NEAR ZERO UNDER THE    
  HEAVIEST STORMS. ADDITIONAL THUNDERSTORMS WILL BE POSSIBLE DURING  
  THE EARLY MORNING HOURS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES
AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING SPOTS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. DO
NOT ENTER THE WATER. TURN AROUND AND MOVE UP TO HIGHER GROUND TO
ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS SUBJECT TO FLOODING WHEN
WATER BEGINS RISING.

&&

LAT...LON 4151 8723 4148 8757 4157 8779 4168 8798
      4199 8825 4202 8766 4191 8762 4190 8760
      4184 8760 4175 8753 4170 8751 4168 8745
      4169 8742 4167 8741 4165 8742 4163 8733
      4162 8722

$$

CMS

5 follow-up statements

682 
WGUS73 KLOT 230726
FFSLOT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
226 AM CDT SAT JUL 23 2011

ILC031-043-INC089-231230-
/O.CON.KLOT.FF.W.0020.000000T0000Z-110723T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DUPAGE IL-COOK IL-LAKE IN-
226 AM CDT SAT JUL 23 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHERN LAKE...COOK 
AND NORTHEASTERN DUPAGE COUNTIES UNTIL 730 AM CDT...

AT 226 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
SLOW MOVING THUNDERSTORMS PRODUCING TORRENTIAL RAINFALL...MOVING 
SOUTHEAST ACROSS DUPAGE AND COOK COUNTIES. RAINFALL RATES UP TO 3 
INCHES PER HOUR ARE POSSIBLE FROM THESE THUNDERSTORMS. THIS AMOUNT 
OF RAINFALL CAN QUICKLY CAUSE FLASH FLOODING...ESPECIALLY IN URBAN 
AREAS.

WIDESPREAD AND SIGNIFICANT FLOODING HAS BEEN REPORTED IN THE CITY 
OF CHICAGO WITH CARS STUCK IN FLOOD WATERS ON CHICAGO AVENUE AND 
THE OHIO STREET RAMP TO INTERSTATE 94 WAS CLOSED. CHICAGO OHARE 
AIRPORT MEASURED 2.34 INCHES OF RAIN BETWEEN 1251 AM AND 151 AM. 

AN ADDITIONAL 1 TO 3 INCHES OF RAIN IS POSSIBLE THROUGH 4 AM CDT. 
MORE AREAS AND ROADS WILL LIKELY BECOME FLOODED AND IMPASSIBLE. 

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. VISIBILITIES WILL ALSO BE REDUCED TO NEAR ZERO UNDER THE    
HEAVIEST STORMS. ADDITIONAL THUNDERSTORMS WILL BE POSSIBLE DURING  
THE EARLY MORNING HOURS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE ELEVATED LEVELS ON SMALL
CREEKS AND STREAMS...PONDING OF WATER ON ROADS...URBAN AREAS...
HIGHWAYS... UNDERPASSES AND LOW LYING AREAS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLOODING IS OBSERVED...ACT QUICKLY. DO NOT
ENTER THE WATER. TURN AROUND AND MOVE UP TO HIGHER GROUND. DO NOT
STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

&&

LAT...LON 4151 8723 4148 8757 4157 8779 4168 8798
      4199 8825 4202 8766 4191 8762 4190 8760
      4184 8760 4175 8753 4170 8751 4168 8745
      4169 8742 4167 8741 4165 8742 4163 8733
      4162 8722

$$

CMS

455 
WGUS73 KLOT 230829
FFSLOT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
329 AM CDT SAT JUL 23 2011

ILC031-043-INC089-231230-
/O.CON.KLOT.FF.W.0020.000000T0000Z-110723T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DUPAGE IL-COOK IL-LAKE IN-
329 AM CDT SAT JUL 23 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHERN LAKE...COOK 
AND NORTHEASTERN DUPAGE COUNTIES UNTIL 730 AM CDT...

AT 329 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
SLOW MOVING THUNDERSTORMS PRODUCING TORRENTIAL RAINFALL...MOVING 
SOUTHEAST ACROSS EASTERN DUPAGE AND COOK COUNTIES. RAINFALL RATES 
UP TO 2 INCHES PER HOUR ARE POSSIBLE FROM THESE THUNDERSTORMS. THIS 
AMOUNT OF RAINFALL CAN QUICKLY CAUSE FLASH FLOODING...ESPECIALLY IN 
URBAN AREAS.

WIDESPREAD AND SIGNIFICANT FLOODING HAS BEEN REPORTED IN THE CITY 
OF CHICAGO WITH CARS STUCK IN FLOOD WATERS ON CHICAGO AVENUE AND 
THE OHIO STREET RAMP TO INTERSTATE 94 WAS CLOSED. MANY VIADUCTS 
HAVE ALSO BEEN FLOODED. CHICAGO OHARE AIRPORT MEASURED 5.53 INCHES 
OF RAIN BETWEEN 1251 AM AND 251 AM.

AN ADDITIONAL 1 TO 2 INCHES OF RAIN IS POSSIBLE THROUGH 430 AM CDT. 
MORE AREAS AND ROADS WILL LIKELY BECOME FLOODED AND IMPASSIBLE. 

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. VISIBILITIES WILL ALSO BE REDUCED TO NEAR ZERO UNDER THE    
HEAVIEST STORMS. ADDITIONAL THUNDERSTORMS WILL BE POSSIBLE DURING  
THE EARLY MORNING HOURS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE ELEVATED LEVELS ON SMALL
CREEKS AND STREAMS...PONDING OF WATER ON ROADS...URBAN AREAS...
HIGHWAYS... UNDERPASSES AND LOW LYING AREAS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLOODING IS OBSERVED...ACT QUICKLY. DO NOT
ENTER THE WATER. TURN AROUND AND MOVE UP TO HIGHER GROUND. DO NOT
STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

&&

LAT...LON 4151 8723 4148 8757 4157 8779 4168 8798
      4199 8825 4202 8766 4191 8762 4190 8760
      4184 8760 4175 8753 4170 8751 4168 8745
      4169 8742 4167 8741 4165 8742 4163 8733
      4162 8722

$$

CMS

473 
WGUS73 KLOT 230943
FFSLOT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
443 AM CDT SAT JUL 23 2011

ILC031-043-INC089-231230-
/O.CON.KLOT.FF.W.0020.000000T0000Z-110723T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DUPAGE IL-COOK IL-LAKE IN-
443 AM CDT SAT JUL 23 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHERN LAKE...COOK 
AND NORTHEASTERN DUPAGE COUNTIES UNTIL 730 AM CDT...

AT 443 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
SHOWERS AND THUNDERSTORMS HAVE WEAKENED CONSIDERABLY ACROSS THE 
WARNED AREA. HOWEVER...ADDITIONAL THUNDERSTORMS OVER WESTERN 
ILLINOIS MAY MOVE ACROSS NORTHEAST ILLINOIS LATER THIS MORNING.

CHICAGO OHARE AIRPORT HAS MEASURED 6.78 INCHES OF RAIN BETWEEN 1251 
AM CDT AND 351 AM CDT.

RAPID RISES HAVE OCCURRED ON MANY RIVERS AND CREEKS IN THE WARNED 
AREA...AND MAY RISE ABOVE FLOOD STAGE AS RUNOFF FROM HEAVY RAIN 
CONTINUES TO DRAIN INTO THE WATERWAYS...INCLUDING THE NORTH BRANCH 
OF THE CHICAGO RIVER...THE DES PLAINES RIVER...THE SKOKIE RIVER AND 
WELLER CREEK.

WIDESPREAD AND SIGNIFICANT FLOODING HAS BEEN REPORTED IN THE CITY 
OF CHICAGO WITH CARS STUCK IN FLOOD WATERS ON CHICAGO AVENUE AND 
THE OHIO STREET RAMP TO INTERSTATE 94 WAS CLOSED. MANY VIADUCTS 
HAVE ALSO BEEN FLOODED.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE ELEVATED LEVELS ON SMALL
CREEKS AND STREAMS...PONDING OF WATER ON ROADS...URBAN AREAS...
HIGHWAYS... UNDERPASSES AND LOW LYING AREAS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLOODING IS OBSERVED...ACT QUICKLY. DO NOT
ENTER THE WATER. TURN AROUND AND MOVE UP TO HIGHER GROUND. DO NOT
STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

&&

LAT...LON 4151 8723 4148 8757 4157 8779 4168 8798
      4199 8825 4202 8766 4191 8762 4190 8760
      4184 8760 4175 8753 4170 8751 4168 8745
      4169 8742 4167 8741 4165 8742 4163 8733
      4162 8722

$$

CMS

924 
WGUS73 KLOT 231107
FFSLOT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
607 AM CDT SAT JUL 23 2011

ILC031-043-INC089-231230-
/O.CON.KLOT.FF.W.0020.000000T0000Z-110723T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DUPAGE IL-COOK IL-LAKE IN-
607 AM CDT SAT JUL 23 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHERN LAKE...COOK AND
NORTHEASTERN DUPAGE COUNTIES UNTIL 730 AM CDT...

AT 557 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
SHOWERS AND THUNDERSTORMS HAVE SINCE EXITED THE WARNED AREA. 
HOWEVER...ADDITIONAL THUNDERSTORMS OVER WESTERN AND NORTH CENTRAL
ILLINOIS MAY MOVE ACROSS NORTHEAST ILLINOIS LATER THIS MORNING 
PROVIDING ADDITIONAL RAINFALL TO AREAS WHICH HAVE RECEIVED BETWEEN 
FOUR AND SEVEN INCHES.

AS OF 6 AM CDT...CHICAGO OHARE AIRPORT HAS MEASURED 6.85 INCHES OF 
RAINFALL.

DUE TO THESE HIGH RAINFALL TOTALS...RAPID RISES HAVE OCCURRED ON 
MANY RIVERS AND CREEKS IN THE WARNED AREA...AND MAY RISE ABOVE FLOOD 
STAGE AS RUNOFF FROM HEAVY RAIN CONTINUES TO DRAIN INTO THE 
WATERWAYS...INCLUDING THE NORTH BRANCH OF THE CHICAGO RIVER...THE 
DES PLAINES RIVER...THE SKOKIE RIVER AND WELLER CREEK.

WIDESPREAD AND SIGNIFICANT FLOODING HAS BEEN REPORTED IN THE CITY 
OF CHICAGO WITH CARS STUCK IN FLOOD WATERS ON CHICAGO AVENUE AND 
THE OHIO STREET RAMP TO INTERSTATE 94 WAS CLOSED. MANY VIADUCTS 
HAVE ALSO BEEN FLOODED. ALSO..BOTH IN BOUNDS AND OUT BOUNDS OF 
INTERSTATE 190 INTO OHARE HAVE BEEN CLOSED DUE TO FLOODED WATERS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE ELEVATED LEVELS ON SMALL
CREEKS AND STREAMS...PONDING OF WATER ON ROADS...URBAN AREAS...
HIGHWAYS... UNDERPASSES AND LOW LYING AREAS.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

LAT...LON 4151 8723 4148 8757 4157 8779 4168 8798
      4199 8825 4202 8766 4191 8762 4190 8760
      4184 8760 4175 8753 4170 8751 4168 8745
      4169 8742 4167 8741 4165 8742 4163 8733
      4162 8722

$$

RODRIGUEZ

887 
WGUS73 KLOT 231233
FFSLOT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
733 AM CDT SAT JUL 23 2011

ILC031-043-INC089-231248-
/O.EXP.KLOT.FF.W.0020.000000T0000Z-110723T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DUPAGE IL-COOK IL-LAKE IN-
733 AM CDT SAT JUL 23 2011

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR NORTHERN LAKE...
COOK AND NORTHEASTERN DUPAGE COUNTIES HAS BEEN REPLACED WITH A NEW 
FLASH FLOOD WARNING THIS MORNING WITH FLOODING CONTINUING ACROSS 
MANY AREAS.

LAT...LON 4151 8723 4148 8757 4157 8779 4168 8798
      4199 8825 4202 8766 4191 8762 4190 8760
      4184 8760 4175 8753 4170 8751 4168 8745
      4169 8742 4167 8741 4165 8742 4163 8733
      4162 8722

$$

RODRIGUEZ

What forecasters said that day

The local office's own words before this flash flood 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 flash flood warning went out at Jul 23, 12:59 AM CDT, 20 minutes earlier.

Area forecast discussion, Jul 23, 12:59 AM CDT, 20 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1259 AM CDT SAT JUL 23 2011

.DISCUSSION...
354 PM CDT

HEAT AND THE PROSPECTS OF MORE HEAVY RAINFALL ARE THE MAIN FORECAST
CONCERNS OVER THE NEXT FEW DAYS.

AS FOR THE HEAT HEADLINES...I DECIDED TO CANCEL THE HEAT WATCH FOR
THE NORTHERN SECTIONS OF THE AREA...GENERALLY ALONG AND NORTH OF I-88
AS IT APPEARS UNLIKELY FOR THESE AREAS TO REACH THE DANGEROUS
CRITERIA.  IN SPITE OF THIS...THINGS SHOULD BEGIN WARMING BACK TO
NEAR 90 IN THESE AREAS...ESPECIALLY BY SUNDAY.  FARTHER
SOUTH...GENERALLY SOUTH OF I-80 I EXTENDED THE WARNING THROUGH 02
UTC ON MONDAY. IN THE MIDDLE I LEFT THE WATCH FROM 12 UTC SUNDAY TO
02 MONDAY. THIS IS FOR AREAS ALONG THE I-80 CORRIDOR.

A POTENT MID LEVEL SHORT WAVE WILL SHIFT EASTWARD ACROSS NORTH
DAKOTA TONIGHT INTO SATURDAY. IN RESPONSE TO THIS...A SURFACE LOW IS
EXPECTED SHIFT EASTWARD FROM THE NORTHERN HIGH PLAINS TO SOUTHERN MN
BY SATURDAY EVENING. THIS WILL CAUSE THE WARM FRONT...CURRENTLY
ACROSS THE AREA...TO MOVE NORTHWARD TO SOUTHERN WI TONIGHT. SEVERAL
MID LEVEL DISTURBANCES EJECTING OUT ACROSS CENTRAL PLAINS...WILL
CONTINUE TO DEVELOP CONVECTION ACROSS IOWA THIS EVENING. WITH TIME
TONIGHT GOOD MOIST ADVECTION WITHIN A WARM AIR ADVECTION REGIME
SHOULD ALLOW THIS ACTIVITY TO CONGEAL INTO ANOTHER MCS. IT APPEARS
THAT THIS MCS COULD HIT THE SAME AREAS AS THIS MORNINGS MCS.
ADDITIONALLY...GIVEN THAT THE ATMOSPHERIC PROFILE HAS CHANGED
LITTLE...IT CAN BE EXPECTED THAT THESE STORMS WILL ALSO BE EFFICIENT
RAINMAKERS. THIS ACTIVITY SHOULD CONTINUE ON SATURDAY MORNING ACROSS
THE AREA. IN ADDITION TO THE HEAVY RAIN...STRONG WINDS ARE AGAIN POSSIBLE
WITH THESE STORMS.

SIMILAR TO TODAY...IT APPEARS THERE WILL BE SOME DRY TIME IN THE
AFTERNOON. HOWEVER...ADDITIONAL CONVECTIVE DEVELOPMENT COULD OCCUR
AGAIN BY LATE AFTERNOON. HOWEVER...IF THE LOW LEVEL WIND FIELD IS
SIGNIFICANTLY DISRUPTED...AS IT WAS TODAY...IT MAY LIMIT THE
OVERALL THREAT ACROSS THE AREA...EXCEPT NEAR ANY BOUNDARIES THAT
BECOME ESTABLISHED.

A FINAL ROUND OF THUNDERSTORMS LOOKS TO BE IN THE WORKS BY SUNDAY
AFTERNOON AS THE COLD FRONT FINALLY PUSHES ACROSS THE AREA. THERE
COULD BE A SOME STRONG TO SEVERE STORMS DURING THIS PERIOD.
HOWEVER...THE MAIN STORY WITH THIS FRONT WILL BE THE PLEASANT AIR
MASS IT USHERS IN ACROSS THE REGION. SURFACE HIGH PRESSURE WILL
BUILD IN ACROSS THE WESTERN GREAT LAKES IN THE WAKE OF THIS FRONT ON
MONDAY AND TUESDAY. THIS WILL PRODUCE COOL AND DRY CONDITIONS FOR
MONDAY AND TUESDAY. UNFORTUNATELY...THIS WILL BE RELATIVELY SHORT
LIVED AS THE THE HEAT MAKES A RETURN BY WEDNESDAY AND THURSDAY AS
THE UPPER RIDGE BUILDS NORTHWARD AGAIN. THIS COULD PUT TEMPERATURES
BACK INTO THE MID 90S AREA WIDE BY THURSDAY

KJB

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* VCTS ARRIVES AROUND 7Z...THEN A LINE OF CONVECTION ARRIVING
  BETWEEN 7-8Z AND LINGERING TSRA THROUGH 10Z.
* SOUTHWEST WINDS LESS THAN 10 KT...WITH TSRA WINDS BECOME VRB FOR
  A FEW HOURS. GUSTS WITHIN TSRA COULD GO ABOVE 30KT FOR A PERIOD
  OF TIME ON LEADING EDGE.

BEACHLER

//DISCUSSION...UPDATED 06Z...

CONVECTION BUILDING AS I TYPE THIS DISCUSSION ACROSS ALL OF
NORTHEAST ILLINOIS AND A LINE OF THUNDERSTORMS SLIDING EAST ACROSS
NORTHWEST ILLINOIS. THUNDERSTORMS ARE EXPECTED TO CONTINUE TO BE
PERIDODIC THROUGHOUT THE TAF...AND GUIDANCE HAS NOT HANDLED THE
CURRENT CONVECTION WELL. OVERALL EXPECT TEMPO CONVECTION THROUGH
10Z...THEN IT APPEARS A BRIEF LULL IN THE CONVECTION AROUND
DAYBREAK. NEXT ROUND OF CONVECTION IS EXPECTED TO DEVELOP AFTER
16Z. PRECISE TIMING AND PLACEMENT OF CONVECTION REMAINS A LOW
CONFIDENCE.

THE MAIN WIND FLOW CONTINUES TO BE SOUTHERLY TO AT TIMES
SOUTHWESTERLY. THIS APPEARS TO BE THE ONLY ELEMENT WITH THE
HIGHEST CONFIDENCE THROUGHOUT THE TAF.

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* MEDIUM-HIGH CONFIDENCE ON TIMNIG AND COVERAGE OF TSRA BTWN
  07-10Z AT ORD/MDW.
* MEDIUM CONFIDENCE ON WIND DIR/SPEED.
* LOW-MEDIUM CONFIDENCE ON CIGS.
* LOW CONFIDENCE ON VSBYS IN AND AROUND TSRA.
* MEDIUM CONFIDENCE IN TAF AFTER 11Z.

BEACHLER

//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...

SUNDAY...CHC TSRA.

MONDAY...VFR.

TUESDAY...VFR.

WEDNESDAY...VFR.

THURSDAY...VFR. SLGT CHC TSRA.

RATZER

&&

.MARINE...
414 PM CDT

GENERALLY SOUTHERLY FLOW IN PLACE ACROSS THE LAKE LATE THIS
AFTERNOON...WITH RATHER LIGHT WINDS ALSO IN PLACE AS PRESSURE
GRADIENT REMAINS BAGGY. TROUGH OF LOW PRESSURE TO THE NORTH WILL
CONTINUE TO SHIFT EAST WITH TIME TONIGHT...WITH A RIDGE OF HIGH
PRESSURE BUILDING IN OVER THE LAKE FROM THE NORTH. WINDS WILL
CONTINUE TO REMAIN LIGHT WITH THE EXCEPTION FOR AREAS ACROSS THE
NORTHERN HALF WHERE THIS BUILDING HIGH PRESSURE WILL HELP TO
TIGHTEN THE PRESSURE GRADIENT AS WELL AS INCREASE THE WINDS. THEN
AS A TROUGH OF LOW PRESSURE WORKS ITS WAY NORTHEAST THROUGH THE
PLAINS AND UPPER MIDWEST INTO THE CENTRAL GREAT LAKES REGION
SATURDAY NIGHT INTO SUNDAY...WINDS WILL TURN TO THE SOUTH.
ALTHOUGH A RIDGE OF HIGH PRESSURE BUILDING IN FROM THE WEST WILL
HELP THE WINDS TURN MORE NORTHERLY WITH WINDS PICKING UP ONCE
AGAIN BEFORE THE RIDGE AXIS SHIFTS OVERHEAD.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...EXCESSIVE HEAT WARNING...ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 9 PM
     SUNDAY.

     EXCESSIVE HEAT WATCH...ILZ019-ILZ020-ILZ021-ILZ022...7 AM
     SATURDAY TO 9 PM SUNDAY.

IN...EXCESSIVE HEAT WATCH...INZ001-INZ002...7 AM SATURDAY TO 9 PM
     SUNDAY.

     EXCESSIVE HEAT WARNING...INZ010-INZ011-INZ019 UNTIL 9 PM SUNDAY.

LM...NONE.
&&

Hazardous weather outlook, Jul 22, 4:27 PM CDT, 8 hours 52 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
427 PM CDT FRI JUL 22 2011

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
232130-
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-
427 PM CDT FRI JUL 22 2011 /527 PM EDT FRI JUL 22 2011/

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

.DAY ONE...TONIGHT.

  WEATHER HAZARDS EXPECTED:

  OPPRESSIVE HEAT AND HUMIDITY.

  THUNDERSTORMS...SOME MAY PRODUCE:
    HEAVY RAINFALL WITH FLASH FLOODING.
    WINDS OVER 60 MPH.
    FREQUENT LIGHTNING.

  AREAS AFFECTED AND TIMING:

   THE DANGEROUS HEAT AND HUMIDITY WILL CONTINUE...ESPECIALLY
   SOUTH OF INTERSTATE 80.

   THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS IOWA THIS
   EVENING...BEFORE THEY TRACK EASTWARD ACROSS SOUTHERN WISCONSIN
   AND FAR NORTHERN ILLINOIS LATE TONIGHT INTO SATURDAY MORNING.
   AREAS NORTH OF INTERSTATE 80 WILL HAVE THE BEST CHANCE OF
   THUNDERSTORMS.

  DISCUSSION:

   HEAT INDEX VALUES WILL LIKELY ONLY DROP TO THE LOW 90S BY
   MIDNIGHT TONIGHT FOR AREAS SOUTH OF I-80. THIS WILL CONTINUE TO
   LEAD TO DANGEROUS HEAT CONDITIONS.

   VERY HEAVY RAINFALL MAY AGAIN ACCOMPANY THE THUNDERSTORMS LATE
   TONIGHT INTO SATURDAY MORNING. THIS RAIN COULD FALL ON THE SAME
   AREAS THAT EXPERIENCED HEAVY RAIN THIS MORNING. RUNOFF FROM
   THIS RAIN COULD CAUSE ADDITIONAL FLASH FLOODING IN SOME AREAS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

HEAT INDEX VALUES AROUND 100 DEGREES ARE EXPECTED ACROSS MUCH OF
NORTHERN ILLINOIS AND NORTHWEST INDIANA FOR THE WEEKEND. SOUTH OF
I-80 THE HEAT WILL BE MORE EXTREME...HEAT INDEX VALUES AROUND 110
DEGREES ARE EXPECTED.

THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS THROUGH SUNDAY
AND AGAIN BY THE MIDDLE OF NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATE TONIGHT INTO SATURDAY
MORNING.

&&

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

LMZ740>745-232130-
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-
427 PM CDT FRI JUL 22 2011

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

.DAY ONE...TONIGHT.

THERE IS A CHANCE OF STORMS LATE TONIGHT CAUSING WIND GUSTS IN
EXCESS OF 35 KNOTS AND FREQUENT LIGHTNING.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS THROUGH SUNDAY
AND AGAIN BY THE MIDDLE OF NEXT WEEK.

&&

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

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-232130-
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-
427 PM CDT FRI JUL 22 2011

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

.DAY ONE...TONIGHT.

THERE IS A CHANCE OF STORMS LATE TONIGHT CAUSING WIND GUSTS
IN EXCESS OF 35 KNOTS AND FREQUENT LIGHTNING.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE
THROUGH SUNDAY.

THERE ARE ADDITIONAL CHANCES FOR THUNDERSTORMS TUESDAY NIGHT
THROUGH THURSDAY...MAINLY FOR THE NORTHERN HALF OF THE LAKE.

&&

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

KJB

In the hours before

Local storm report, Jul 22, 8:08 PM CDT, 5 hours 11 minutes before

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
808 PM CDT FRI JUL 22 2011

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

0530 AM     HEAVY RAIN       7 W ROCKTON             42.45N 89.21W
07/22/2011  M0.92 INCH       WINNEBAGO          IL   CO-OP OBSERVER

            MEASURED BY SHIRLAND CO-OP OBSERVER.

0630 AM     HEAVY RAIN       1 W BEACH PARK          42.42N 87.88W
07/22/2011  M2.19 INCH       LAKE               IL   COCORAHS

            STORM TOTAL SO FAR. 0.70 INCHES MEASURED IN THE PAST 60
            MINUTES. STANDING WATER AND DITCHES FILLING UP.

0700 AM     HEAVY RAIN       2 W GURNEE              42.38N 87.98W
07/22/2011  M2.24 INCH       LAKE               IL   COCORAHS

0700 AM     HEAVY RAIN       HARVARD                 42.42N 88.62W
07/22/2011  M1.17 INCH       MCHENRY            IL   CO-OP OBSERVER

0700 AM     HEAVY RAIN       2 N SPRING GROVE        42.47N 88.24W
07/22/2011  M1.71 INCH       MCHENRY            IL   CO-OP OBSERVER

0700 AM     HEAVY RAIN       5 NW WOODSTOCK          42.36N 88.51W
07/22/2011  M1.48 INCH       MCHENRY            IL   CO-OP OBSERVER

0700 AM     HEAVY RAIN       2 N WAUKEGAN            42.40N 87.87W
07/22/2011  M2.10 INCH       LAKE               IL   COCORAHS

0700 AM     HEAVY RAIN       2 SE LAKEMOOR           42.32N 88.18W
07/22/2011  M1.69 INCH       LAKE               IL   COCORAHS

0700 AM     HEAVY RAIN       1 W BEACH PARK          42.42N 87.88W
07/22/2011  M1.49 INCH       LAKE               IL   COCORAHS

0700 AM     HEAVY RAIN       BEACH PARK              42.42N 87.86W
07/22/2011  M2.06 INCH       LAKE               IL   ASOS

            SINCE 100 AM AT WAUKEGAN REGIONAL AIRPORT.

0700 AM     HEAVY RAIN       2 NE GURNEE             42.40N 87.91W
07/22/2011  M2.38 INCH       LAKE               IL   COCORAHS

0725 AM     HEAVY RAIN       WADSWORTH               42.44N 87.92W
07/22/2011  M2.80 INCH       LAKE               IL   BROADCAST MEDIA

            0.50 INCHES BETWEEN 655 AM AND 715 AM.

0745 AM     FLOOD            BEACH PARK              42.42N 87.86W
07/22/2011                   LAKE               IL   EMERGENCY MNGR

            NORTH SHERIDAN ROAD SOUTH OF WEST WADSWORTH ROAD CLOSED
            FROM 745 AM TO 100 PM DUE TO 7-8 INCHES OF STANDING WATER
            ON ROAD SURFACE.

0750 AM     HEAVY RAIN       3 ENE MACHESNEY PARK    42.38N 88.98W
07/22/2011  M1.09 INCH       WINNEBAGO          IL   COCORAHS

0755 AM     HEAVY RAIN       GURNEE                  42.38N 87.94W
07/22/2011  M3.25 INCH       LAKE               IL   PUBLIC

            STORM TOTAL SO FAR.

0800 AM     HEAVY RAIN       WINTHROP HARBOR         42.48N 87.83W
07/22/2011  M1.28 INCH       LAKE               IL   COCORAHS

0842 AM     HEAVY RAIN       4 NW ROCKFORD           42.31N 89.12W
07/22/2011  M1.37 INCH       WINNEBAGO          IL   CO-OP OBSERVER

            STORM TOTAL SO FAR. 0.95 INCHES BETWEEN 715 AM AND TIME
            OF REPORT.

0900 AM     HEAVY RAIN       ARLINGTON HEIGHTS       42.09N 87.98W
07/22/2011  E0.00 INCH       COOK               IL   TRAINED SPOTTER

            ESTIMATED 1 TO 2 INCHES.

0920 AM     HEAVY RAIN       3 NNE ELBURN            41.93N 88.45W
07/22/2011  M0.63 INCH       KANE               IL   COCORAHS

            IN 15 MINUTES.

0933 AM     TSTM WND GST     DUPAGE AIRPORT          41.92N 88.25W
07/22/2011  M45.00 MPH       DUPAGE             IL   ASOS

0945 AM     TSTM WND GST     ELMHURST                41.90N 87.94W
07/22/2011  M56.50 MPH       DUPAGE             IL   TRAINED SPOTTER

            MEASURED WITH A CAR ANEMOMETER. BRYAN MIDDLE SCHOOL AT
            YORK ROAD.

0947 AM     TSTM WND GST     OHARE AIRPORT           41.98N 87.90W
07/22/2011  M43.00 MPH       COOK               IL   ASOS

0953 AM     HEAVY RAIN       ARLINGTON HEIGHTS       42.09N 87.98W
07/22/2011  M1.00 INCH       COOK               IL   TRAINED SPOTTER

            IN 15 MINUTES UP TO TIME OF REPORT.

0955 AM     HEAVY RAIN       OHARE AIRPORT           41.98N 87.90W
07/22/2011  M0.75 INCH       COOK               IL   ASOS

            MEASURED IN 8 MINUTES BETWEEN 947AM AND 955 AM. 0.55
            INCHES FELL BETWEEN 947 AM AND 951 AM.

0957 AM     HEAVY RAIN       1 NNE BLOOMINGDALE      41.96N 88.08W
07/22/2011  M0.87 INCH       DUPAGE             IL   COCORAHS

            MEASURED IN 25 MINUTES UP TO TIME OF REPORT.

1000 AM     HEAVY RAIN       3 ESE PLAINFIELD        41.60N 88.15W
07/22/2011  M0.76 INCH       WILL               IL   COCORAHS

            IN THE PAST 30 MINUTES.

1000 AM     HEAVY RAIN       GLEN ELLYN              41.87N 88.06W
07/22/2011  M1.16 INCH       DUPAGE             IL   COCORAHS

            RAINFALL IN ONE HOUR IN NORTH GLEN ELLYN.

1000 AM     HEAVY RAIN       1 W ROSELLE             41.98N 88.10W
07/22/2011  M0.91 INCH       DUPAGE             IL   COCORAHS

            BETWEEN 940 AM AND 1000 AM.

1006 AM     TSTM WND GST     MIDWAY AIRPORT          41.78N 87.75W
07/22/2011  M54.00 MPH       COOK               IL   ASOS

1013 AM     HEAVY RAIN       ARLINGTON HEIGHTS       42.09N 87.98W
07/22/2011  M0.85 INCH       COOK               IL   TRAINED SPOTTER

            IN 30 MINUTES UP TO TIME OF REPORT. INTERSECTION OF HINTZ
            RD AND WINDSOR.

1015 AM     MARINE TSTM WIND 4 NE CHICAGO            41.92N 87.57W
07/22/2011  M50.00 MPH       LMZ741             IL   C-MAN STATION

            43 KNOT GUST MEASURED AT HARRISON-DEVER CRIB. 35
            KNOT...OR 40 MPH...SUSTAINED WINDS. ANEMOMETER 85 FEET
            ABOVE LAKE SURFACE.

1026 AM     HEAVY RAIN       MARENGO                 42.25N 88.60W
07/22/2011  E1.80 INCH       MCHENRY            IL   PUBLIC

            MEASURED...BUT FIRST 10-15 MINUTES EXTREMELY HEAVY RAIN
            WAS BLOWING SIDEWAYS...SO TOTAL MAY BE SLIGHTLY UNDER
            WHAT ACTUALLY OCCURRED.

1030 AM     HEAVY RAIN       2 WSW ELK GROVE VILLAGE 41.99N 88.03W
07/22/2011  M1.72 INCH       DUPAGE             IL   COCORAHS

            1.13 INCHES FROM 930 AM TO 1030 AM. 1.72 INCHES IN LAST
            14 HOURS.

1030 AM     HEAVY RAIN       1 W BEACH PARK          42.42N 87.88W
07/22/2011  M3.80 INCH       LAKE               IL   COCORAHS

1053 AM     TSTM WND GST     GARY                    41.60N 87.34W
07/22/2011  M54.00 MPH       LAKE               IN   AWOS

            MEASURED AT GARY AIRPORT.

1054 AM     HEAVY RAIN       PEOTONE                 41.33N 87.80W
07/22/2011  M0.61 INCH       WILL               IL   TRAINED SPOTTER

            HEAVY RAIN FALL IN 16 MINUTES.

1058 AM     HEAVY RAIN       ENE COUNTRYSIDE         41.78N 87.88W
07/22/2011  M1.30 INCH       COOK               IL   COCORAHS

            IN THE PAST 60 MINUTES. AT 1030 AM AND 1035 AM RAIN RATE
            WAS 5 INCHES PER HOUR.

1100 AM     MARINE TSTM WIND 3 NNW BURNS HARBOR      41.65N 87.15W
07/22/2011  M44.00 MPH       LMZ745             IN   C-MAN STATION

            38 KNOT GUST MEASURED AT BURNS HARBOR GLOS WEATHER
            STATION. ANEMOMETER HEIGHT 33 FEET.

1100 AM     HEAVY RAIN       ELBURN                  41.89N 88.47W
07/22/2011  M1.32 INCH       KANE               IL   TRAINED SPOTTER

            RAINFALL TOTAL 1.32 INCHES FROM 1 AM THROUGH 10 AM.

1140 AM     HEAVY RAIN       BERWYN                  41.84N 87.79W
07/22/2011  M1.02 INCH       COOK               IL   TRAINED SPOTTER

0100 PM     HEAVY RAIN       BEACH PARK              42.42N 87.86W
07/22/2011  M3.42 INCH       LAKE               IL   ASOS

            STORM TOTAL SINCE 100 AM AT WAUKEGAN REGIONAL AIRPORT.
            1.36 INCHES BETWEEN 700 AM AND 100 PM.

0100 PM     HEAVY RAIN       OHARE AIRPORT           41.98N 87.90W
07/22/2011  M1.49 INCH       COOK               IL   ASOS

            STORM TOTAL SINCE 100 AM. 1.29 INCHES BETWEEN 700 AM AND
            100 PM.

0102 PM     HEAVY RAIN       REMINGTON               40.76N 87.15W
07/22/2011  M0.63 INCH       JASPER             IN   TRAINED SPOTTER

            MEASURED IN 40 MINUTES.

&&
THIS REPORT MAY BE REVISED IF ANY FURTHER REPORTS ARE RECEIVED.

BN

Local storm report, Jul 22, 11:55 PM CDT, 1 hour 24 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1155 PM CDT FRI JUL 22 2011

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

1145 PM     HAIL             5 E LOWELL              41.29N 87.32W
07/22/2011  E0.25 INCH       LAKE               IN   LAW ENFORCEMENT

            INTERSECTION OF INTERSTATE 65 AND ROUTE 2. FROM INDIANA
            STATE POLICE.

&&

RATZER

Special weather statement, Jul 23, 12:11 AM CDT, 1 hour 8 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1211 AM CDT SAT JUL 23 2011

ILZ003-008-010-230615-
LEE IL-OGLE IL-WINNEBAGO IL-
1211 AM CDT SAT JUL 23 2011

...SPECIAL WEATHER STATEMENT...

AT 1207 AM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED STRONG
THUNDERSTORMS ALONG A LINE EXTENDING FROM 11 MILES WEST OF LAKE
SUMMERSET TO FORRESTON TO POLO...MOVING EAST AT 30 MPH.

WINDS UP TO 50 MPH...FREQUENT CLOUD TO GROUND LIGHTNING...BRIEF HEAVY
DOWNPOURS...ARE POSSIBLE WITH THESE STORMS.

ADDITIONAL ISOLATED THUNDERSTORMS WERE DEVELOPING FARTHER EAST INTO
SOUTHERN MCHENRY AND LAKE COUNTIES.

LOCATIONS IMPACTED INCLUDE...
  POLO...               FORRESTON...          DURAND...
  LAKE SUMMERSET...     PECATONICA...         MOUNT MORRIS...
  WINNEBAGO...          STILLMAN VALLEY...    OREGON...
  BYRON...              ROSCOE...             ROCKTON...

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 CAN LEAD TO FLOODING OF LOW LYING AREAS SUCH AS
DITCHES...VIADUCTS...UNDERPASSES...CREEKS AND DRAINAGE AREAS. SEEK
SHELTER IN A STURDY STRUCTURE UNTIL THESE STORMS HAVE PASSED.

LAT...LON 4250 8896 4182 8896 4187 8964 4192 8963
      4193 8969 4220 8970 4221 8940 4250 8940

RATZER

Local storm report, Jul 23, 12:22 AM CDT, 57 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1222 AM CDT SAT JUL 23 2011

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

1221 AM     HAIL             FORRESTON               42.13N 89.58W
07/23/2011  E0.25 INCH       OGLE               IL   LAW ENFORCEMENT

            PEA HAIL AND 30 TO 40 MPH WINDS. FROM OGLE COUNTY
            SHERIFF.

&&

RATZER

Local storm report, Jul 23, 12:46 AM CDT, 33 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1246 AM CDT SAT JUL 23 2011

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

1242 AM     TSTM WND GST     MACHESNEY PARK          42.36N 89.04W
07/23/2011  E50 MPH          WINNEBAGO          IL   TRAINED SPOTTER

            SMALL BRANCHES DOWN.

&&

RATZER

Local storm report, Jul 23, 12:47 AM CDT, 32 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1247 AM CDT SAT JUL 23 2011

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

1243 AM     FLOOD            MACHESNEY PARK          42.36N 89.04W
07/23/2011                   WINNEBAGO          IL   TRAINED SPOTTER

            STREET FLOODING BEGINNING AT WINDSOR AND ROUTE 251.

&&

RATZER

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 23, 12:11 AM CDT	Special Weather Statement	LOT	Ogle, Winnebago	64 min
Jul 23, 12:36 AM CDT	Flash Flood Warning	LOT	Boone, Cook, DeKalb, Kane, Lake, McHenry and 2 more	6 hr
Jul 23, 12:41 AM CDT	Severe Thunderstorm Warning	LOT	Boone, DeKalb, Lee, McHenry, Ogle, Winnebago	64 min
Jul 23, 12:53 AM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage	54 min
Jul 23, 12:58 AM CDT	Special Marine Warning	LOT		2 hr
Jul 23, 1:50 AM CDT	Special Weather Statement	LOT	DuPage	55 min
Jul 23, 2:37 AM CDT	Flash Flood Warning	LOT	Cook, DuPage, Kane, Kendall, Will	5 hr
Jul 23, 3:00 AM CDT	Special Marine Warning	LOT		48 min
Jul 23, 3:40 AM CDT	Heat Advisory	LOT	DeKalb, Grundy, Kane, Kendall, LaSalle, Lee and 2 more	32 hr
Jul 23, 5:21 AM CDT	River Flood Warning	LOT	Cook	38 hr
Jul 23, 5:21 AM CDT	River Flood Warning	LOT	Cook	3 days
Jul 23, 6:14 AM CDT	River Flood Advisory	LOT	Will	9 hr
Jul 23, 6:30 AM CDT	Flash Flood Warning	LOT	Boone, Cook, DeKalb, Kane, Lake, Lee and 3 more	5 hr
Jul 23, 7:30 AM CDT	Flash Flood Warning	LOT	Cook, DuPage, Kane, Will	4 hr
Jul 23, 9:37 AM CDT	River Flood Warning	LOT	Kane, McHenry	11 hr
Jul 23, 9:37 AM CDT	River Flood Warning	LOT	Kane, Kendall	23 hr
Jul 23, 11:13 AM CDT	Areal Flood Warning	LOT	Cook, DuPage, Lake	19 hr
Jul 23, 2:46 PM CDT	River Flood Warning	LOT	Will	43 hr
Jul 23, 4:15 PM CDT	Flash Flood Watch	LOT	Boone, DeKalb, DuPage, Kane, Kendall, Lake and 4 more	18 hr
Jul 22, 10:20 PM CDT	Flash Flood Warning	LOT	Jasper, Lake, Newton, Porter	6 hr
Jul 23, 8:09 AM CDT	Rip Current Statement	LOT	Lake, Porter	6 hr
Jul 23, 5:27 PM CDT	Special Weather Statement	LOT	Jasper	33 min
Jul 23, 6:41 PM CDT	Areal Flood Advisory	LOT	Jasper, Newton	3 hr

Nearby

Flash Flood Warnings in Illinois, 2011 Flash Flood Warnings in Indiana, 2011 Every flash flood warning in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.