Alert archive / Illinois / Severe Thunderstorm Warnings in 2005
Severe Thunderstorm Warning 79, NWS Chicago, IL
NWS Chicago, IL issued this severe thunderstorm warning at Jul 20, 2005, 7:30 PM CDT for Iroquois County, Kankakee County, Illinois. It was in force for 45 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Jul 20, 2005, 7:30 PM CDT (00:30 UTC)
- Expired
- Jul 20, 2005, 8:15 PM CDT
- In force
- 45 min
- Issued by
- NWS Chicago, IL
- Area
- Counties, with a storm outline in the text
Counties Iroquois County, IL, Kankakee County, IL
The radar
The Chicago radar (KLOT), 76 km from the middle of the area, began a volume at 00:32 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Lincoln, IL (KILX), launched 00:00Z, 0.5 hours before the alert went out and 109 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.
- Mixed-layer CAPE
- 3584 J/kg
- Mixed-layer CIN
- -13 J/kg
- Mixed-layer LCL
- 1174 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 152 m²/s²
- 0-3 km storm-relative helicity
- 245 m²/s²
- Significant tornado parameter
- 2.2
- Supercell composite
- 17.1
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Chicago, IL wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 20, 2:43 PM CDT, 4 hours 47 minutes earlier.
Area forecast discussion, Jul 20, 2:43 PM CDT, 4 hours 47 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 230 PM CDT WED JUL 202005 .DISCUSSION FOR AFTERNOON ZONES/GRIDS... FINALLY SOME WELCOME RAIN WITH PASSING MCS MOVING THROUGH NRN IL/SRN WI. ISOLATED CELLS AHEAD OF THE MAIN LINE PASSING THROUGH NWRN IN AND THE MAIN LINE SHOULD HOLD TOGETHER LONG ENOUGH TO BRING A LITTLE MORE RAIN TO PORTIONS OF NERN IL AND NWRN IN. THIS LEADS IN TO THE IMMEDIATE PROBLEM OF MORE CNVTV ACTIVITY OVERNIGHT. STRONG MOIST, WARM ADVECTION AHEAD OF THE COLD FRONT HAS ALLOWED SIGNIFICANTLY HIGHER DEWPOINTS TO STREAM NORTHWARD...REACHING INTO THE LOW 70S. SO WITH MORE MOISTURE IN PLACE...AN INCREASING LOW-LEVEL JET...MODEST INSTABILITY AND ADEQUATE FORCING...ALL INGREDIENTS POINTING TOWARDS THE CHANCE FOR MORE RAIN OVERNIGHT. THE NAM DEVELOPS SERIOUS FEEDBACK PROBLEMS TONIGHT. THE GFS SEEMS TO BE THE BETTER WAY TO GO FOR THE SFC PATTERN...WITH A SECOND ROUND OF PCPN OVERNIGHT AND PUSHING INTO THE SOUTHERN COUNTIES. BY TOMORROW MORNING...HIGH PRESSURE BUILDING OVER THE NORTHERN GREAT LAKES WILL FORCE THE COLD FRONT SOUTH OF THE CWA...STALLING OUT OVER CENTRAL IL/IN. FOLLOWING THE GFS SFC PATTERN...A DEVELOPING LOW OVER THE NRN PLAINS SHOULD HELP THE FRONT RETURN A LITTLE TO THE NORTH...INCREASING THE CHANCES FOR PCPN OVER THE SOUTHERN PORTIONS OF THE CWA...GENERALLY SOUTH OF I-80 AND THE KANKAKEE RIVER. THE OTHER PROBLEM REMAINS THE HEAT SITUATION FOR SUNDAY AND MONDAY. WILL KEEP WITH THE TRENDS OF PREVIOUS SHIFTS. THE GUIDANCE IS CONSISTENT WITH BUILDING THE UPPER RIDGE OVER THE CENTRAL PLAINS AND SHIFTING OVER THE UPPER MIDWEST. TEMPERATURES SHOULD HAVE NO TROUBLE REACHING INTO THE MIDDLE TO UPPER 90S WITH DEWPOINTS REACHING INTO THE LOW 70S. THIS COMBINATION WOULD GIVE A HEAT INDEX OF 100-105 IN THE CHICAGO METRO AREA AND 105 TO 109 IN LOCATIONS SOUTH OF I-80. KREIN && .AVIATION DISCUSSION REGARDING 12Z TAFS: PERPLEXING QUESTION THIS MRNG IS HOW TO DEAL WITH LINEAR/BOW MCS THAT HAS EVOLVED OVR MN-NRN IA. 06Z ETA12 AND EXPERIMENTAL WRF MODELS BRING THIS INTO RFD AREA ARND 18Z THEN THRU CHI BY 20Z. CURRENT WATER VAPOR SATLT LOOPS SHOW DECENT AREA OF DOWNWARD MOMENTUM BHD THIS TSTM COMPLEX SUGGESTING IT WILL CONTINUE TO BOW ESEWD AS PROGGED. HOWEVER...IR IMAGERY PAST HR HAS SHOWN SOME WARMING IN ANVIL CANOPY...SUGGESTING A WEAKENING TREND...AND A CORRESPONDING DCRS IN LIGHTNING OUTPUT RATE HAS BEEN NOTED. SKIES VFR WITH ONLY A FEW PATCHES OF MID LVL CLOUDINESS AHD OF THIS SYS SO THERE WILL BE PLENTY OF DIURNAL HEATING OVR AREA WITH TEMPS RISING INTO LOWER-MID 90S. IN ADDN...SFC DEWPOINTS IN UPR 60S AND LWR 70S HAVE BEEN ADVECTING NWD AND ARE EXPECTED TO REACH NRN IL-NWRN IND BY ERLY AFTN. AMS FCST TO BECOME VERY UNSTABLE WITH CAPES ABV 4000 AND LIFTED INDEX ARND -8. THINKING IS THAT ALTHO LN IS WEAKENING ATTM...THERE/S ENUF FORCING AS IT WILL BE MOVING INTO UNSTABLE AMS ERLY-MID AFTN TO WARRANT TEMPO MENTION OF THUNDER WITH BRIEF IFR-MVFR CONDS AND WINDSHFT TO WNW. WILL BRING CHC THUNDER IN AGAIN DURG OVERNIGHT HRS AS INDICATIONS ARE THAT STRENGTHENING LLVL JET AND STG ISENTROPIC LIFT WILL PROMOTE NOCTURNAL TSTM DVLPMT. MERZLOCK && .WATCHES/WARNINGS/ADVISORIES... .IL...NONE .IN...NONE .LK MI...NONE
Hazardous weather outlook, Jul 20, 4:00 PM CDT, 3 hours 30 minutes before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 400 PM CDT WED JUL 20 2005 ILZ003>006-008-010>014-019>022-023-032-033-039-INZ001-002-010-011- 019-211100- WINNEBAGO-BOONE-MCHENRY-LAKE IL-OGLE-LEE-DE KALB-KANE-DU PAGE-COOK- LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-IROQUOIS-FORD- LAKE IN-PORTER-NEWTON-JASPER-BENTON- 400 PM CDT WED JUL 20 2005 THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND NORTHEAST ILLINOIS...AND NORTHWEST INDIANA. .DAY ONE... TONIGHT THERE IS A CHANCE FOR SEVERE THUNDERSTORMS PRODUCING STRONG... DAMAGING WINDS OVER MUCH OF NORTHERN ILLINOIS AND NORTHWESTERN INDIANA THROUGH MIDNIGHT TONIGHT. THE MAIN THREAT OF SEVERE THUNDERSTORMS IS CONCENTRATED SOUTH OF I-90 AND ROUTE 20 IN ILLINOIS AND ALL OF NORTHWESTERN INDIANA. SPOTTER ACTIVATION MAY BE REQUIRED THROUGH MIDNIGHT TONIGHT. .DAYS TWO THROUGH SEVEN... THURSDAY THROUGH TUESDAY ON SUNDAY...HEAT INDICES WILL REACH 100 TO 105 ACROSS NORTHERN ILLINOIS NORTH OF I-80. HEAT INDICES WILL REACH 105 TO 110 SOUTH OF I-80...FROM THE KANKAKEE AND ILLINOIS RIVER VALLEYS SOUTHWARD. THESE LEVELS MAY POSE A HAZARD WITH PROLONGED EXPOSURE OR EXTENDED PHYSICAL ACTIVITY....ESPECIALLY TO THOSE WITH SENSITIVITY TO HEAT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE REQUIRED THROUGH MIDNIGHT TONIGHT. && COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO WEBPAGE: WEATHER.GOV/CHICAGO (LOWER CASE) LMZ740>745-766-211100- WINTHROP HARBOR IL TO MICHIGAN CITY IN- LAKE MICHIGAN- 400 PM CDT WED JUL 20 2005 THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR THE ILLINOIS AND INDIANA WATERS OF LAKE MICHIGAN. .DAY ONE... TONIGHT THERE IS A CHANCE FOR SEVERE THUNDERSTORMS THROUGH MIDNIGHT TONIGHT. THESE STORMS HAVE THE POTENTIAL TO PRODUCE STRONG...DAMAGING WINDS OVER THE NEARSHORE WATERS OF LAKE MICHIGAN FROM NORTHERLY ISLAND ILLINOIS TO MICHIGAN CITY INDIANA. THESE STORMS WILL HAVE THE POTENTIAL TO PRODUCE WIND GUSTS TO 50 KNOTS. .DAYS TWO THROUGH SEVEN... THURSDAY THROUGH TUESDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. && COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO WEBPAGE: WEATHER.GOV/CHICAGO (LOWER CASE)
In the hours before
Special weather statement, Jul 20, 2:04 PM CDT, 5 hours 26 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 204 PM CDT WED JUL 20 2005 ILZ006-012>013-019>021-202015- DUPAGE-GRUNDY-KANE-KENDALL-LAKE-LASALLE- 204 PM CDT WED JUL 20 2005 ...THE NATIONAL WEATHER SERVICE HAS CANCELED SEVERE THUNDERSTORM WATCH 651 FOR THE FOLLOWING AREA... IN ILLINOIS THIS CANCELS 6 COUNTIES IN NORTH CENTRAL ILLINOIS LA SALLE... IN NORTHEAST ILLINOIS DUPAGE... GRUNDY... KANE... KENDALL... LAKE... THIS INCLUDES THE CITIES OF...AURORA...MORRIS...OSWEGO... OTTAWA AND WAUKEGAN. ILZ014-022>023-032>033-039-INZ001>002-010>011-019-202300- COOK-FORD-IROQUOIS-KANKAKEE-LIVINGSTON-WILL-BENTON-JASPER-LAKE- NEWTON-PORTER- 204 PM CDT WED JUL 20 2005 ...SEVERE THUNDERSTORM WATCH NUMBER 651 REMAINS VALID UNTIL 6 PM CDT... IN ILLINOIS THIS WATCH INCLUDES 6 COUNTIES IN CENTRAL ILLINOIS LIVINGSTON... IN EAST CENTRAL ILLINOIS FORD... IROQUOIS... IN NORTHEAST ILLINOIS COOK... KANKAKEE... WILL... IN INDIANA THIS WATCH INCLUDES 5 COUNTIES IN NORTHWEST INDIANA BENTON... JASPER... LAKE INDIANA... NEWTON... PORTER... THIS INCLUDES THE CITIES OF...CHICAGO...FOWLER...GARY...JOLIET... KANKAKEE...MOROCCO...PIPER CITY...PONTIAC...RENSSELAER... VALPARAISO AND WATSEKA.
Special weather statement, Jul 20, 3:09 PM CDT, 4 hours 21 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 309 PM CDT WED JUL 20 2005 ILZ014-022>023-032-INZ001>002-202115- COOK-KANKAKEE-LIVINGSTON-WILL-LAKE-PORTER- 309 PM CDT WED JUL 20 2005 ...THE NATIONAL WEATHER SERVICE HAS CANCELED SEVERE THUNDERSTORM WATCH 651 FOR THE FOLLOWING AREA... IN ILLINOIS THIS CANCELS 4 COUNTIES IN CENTRAL ILLINOIS LIVINGSTON... IN NORTHEAST ILLINOIS COOK... KANKAKEE... WILL... IN INDIANA THIS CANCELS 2 COUNTIES IN NORTHWEST INDIANA LAKE... PORTER... THIS INCLUDES THE CITIES OF...CHICAGO...GARY...JOLIET... KANKAKEE...PONTIAC AND VALPARAISO. ILZ033-039-INZ010>011-019-202300- FORD-IROQUOIS-BENTON-JASPER-NEWTON- 309 PM CDT WED JUL 20 2005 ...SEVERE THUNDERSTORM WATCH NUMBER 651 REMAINS VALID UNTIL 6 PM CDT... IN ILLINOIS THIS WATCH INCLUDES 2 COUNTIES IN EAST CENTRAL ILLINOIS FORD... IROQUOIS... IN INDIANA THIS WATCH INCLUDES 3 COUNTIES IN NORTHWEST INDIANA BENTON... JASPER... NEWTON... THIS INCLUDES THE CITIES OF...FOWLER...MOROCCO...PIPER CITY... RENSSELAER AND WATSEKA.
Local storm report, Jul 20, 3:21 PM CDT, 4 hours 9 minutes before
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</html>Special weather statement, Jul 20, 5:48 PM CDT, 1 hour 42 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 548 PM CDT WED JUL 20 2005 ILZ033-039-INZ010>011-019-210000- FORD-IROQUOIS-BENTON-JASPER-NEWTON- 548 PM CDT WED JUL 20 2005 ...THE NATIONAL WEATHER SERVICE HAS CANCELED SEVERE THUNDERSTORM WATCH 651 FOR THE FOLLOWING AREA... IN ILLINOIS THIS CANCELS 2 COUNTIES IN EAST CENTRAL ILLINOIS FORD... IROQUOIS... IN INDIANA THIS CANCELS 3 COUNTIES IN NORTHWEST INDIANA BENTON... JASPER... NEWTON... THIS INCLUDES THE CITIES OF...FOWLER...MOROCCO...PIPER CITY... RENSSELAER AND WATSEKA.
The office that day
Everything else NWS Chicago, IL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 20, 7:13 PM CDT | Severe Thunderstorm Warning | LOT | Grundy, Livingston | 31 min |
| Jul 20, 8:13 PM CDT | Severe Thunderstorm Warning | LOT | Iroquois | 47 min |
| Jul 20, 9:51 PM CDT | Severe Thunderstorm Warning | LOT | Grundy, Kankakee | 30 min |
| Jul 20, 11:57 PM CDT | Severe Thunderstorm Warning | LOT | Ford, Iroquois | 48 min |
| Jul 21, 9:40 AM CDT | Special Marine Warning | LOT | 95 min | |
| Jul 21, 6:54 PM CDT | Severe Thunderstorm Warning | LOT | Ford, Iroquois, Livingston | 51 min |
| Jul 21, 2:46 PM CDT | Severe Thunderstorm Warning | LOT | Porter | 44 min |
Nearby
Severe Thunderstorm Warnings in Illinois, 2005Every severe thunderstorm warning in 2005
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.