Scattered thunderstorms moved across northern Illinois producing sporadic severe wind and hail.
Every event with a place to put it. Tap one for its entry below.
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.
The episode as NWS LOT wrote it up.
Scattered thunderstorms moved across northern Illinois producing sporadic severe wind and hail.
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 Aug 17, 12:05 PM CST, 1 hour 35 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 105 PM CDT MON AUG 17 2015 .UPDATE...1208 PM CDT... NO REAL CHANGES TO THE FORECAST THEME FOR TODAY. CURRENT AMDAR SOUNDINGS OUT OF OHARE/MIDWAY DEPICT A FAIRLY DRY COLUMN WITH WEAK MID LEVEL LAPSE RATES AND A WARM LAYER AT 600-650 MB...BUT SPC MESOANLYSIS SHOWING AN INCREASE IN LOW LEVEL LAPSE RATES GIVEN GOOD SOLAR HEATING. WITH DEWPOINTS IN THE UPPER 60S/LOW 70S IS SUPPORTIVE OF SOME WEAK/MODERATE INSTABILITY. IN SPITE OF LIITLE ACTIVITY THUS FAR AND THESE NEGATIVE FACTORS...MOST HI-RES GUIDANCE CONTINUES TO SUGGEST ISOLATED TO SCATTERED THUNDERSTORM DEVELOPMENT THIS AFTERNOON IN SW FLOW AHEAD OF THE COLD FRONT WITH THE BOUNDARY LAYER DESTABILIZATION AND SOME MINOR COOLING ALOFT...AND THIS HAS INDEED BEGUN TO PLAY OUT. SCATTERED SHOWERS WITH ISOLATED THUNDERSTORMS WILL BE THE RULE INITIALLY AS THE CUMULUS FIELD IS NOT GROWING SUPER DEEP YET...BUT LIKELY WILL INCREASE IN COVERAGE A BIT MORE. LOWER AND HIGHER CLOUDS WILL LIMIT HOW MUCH DESTABILIZATION IS EXPECTED TODAY...BUT GOOD LOW LEVEL LAPSE RATES/DCAPE WILL SUPPORT SOME GUSTY WINDS WITH ANY STORMS THAT GET GOING. HIGHEST POPS IN THE NW CLOSER TO THE FRONT AND FAR SE CLOSER TO THE UPPER WAVE SEEM REASONABLE...WITH SMALLER THOUGH NON-ZERO CHANCES OVER NE ILLINOIS. KMD && .SHORT TERM... 258 AM CDT TODAY THROUGH WEDNESDAY... THUNDERSTORMS AND ASSOCIATED STRONG/SEVERE AND HEAVY RAIN THREATS ARE THE MAIN FOCUS OF THE FORECAST THIS MORNING. WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL LOW OVER THE LOWER OHIO RIVER VALLEY WHICH IS SLOWLY SPINNING NORTHWARD INTO SOUTHEAST IL/SOUTHWEST IN. A LARGE SCALE UPPER TROUGH IS SPREAD ACROSS MUCH OF CENTRAL CANADA AND THE FAR NORTH-CENTRAL U.S. A SERIES OF WAVES ARE EMBEDDED IN THIS TROUGH WITH THE MOST NOTABLE ONE DROPPING SOUTHWARD ACROSS SOUTHERN BRITISH COLUMBIA. AT THE SURFACE...HIGH PRESSURE IS SPREAD OVER THE FAR EASTERN U.S. A COLD FRONT TRAILS A LOW OVER NORTHERN QUEBEC AND STRETCHES SOUTHWESTWARD INTO WISCONSIN AND IOWA. THE INITIAL FOCUS WILL BE ON THE UPPER LOW SPINNING NORTHWARD OVER THE LOW OHIO VALLEY AS IT LIFTS NORTHWARD BUT STARTS TO WEAKEN. THERE MAY BE ENOUGH FORCING TO COMBINE WITH DAYTIME HEATING TO GENERATE SOME ISOLATED/SCATTERED SHOWERS AND STORMS THIS AFTERNOON. ACTIVITY COULD DEVELOP JUST ABOUT ANYWHERE IN THE FORECAST AREA BUT THE MOST FAVORED AREA MAY BE FROM THE CHICAGO METRO SOUTHWEST TO PONTIAC AND POINTS EAST. DEEP LAYER SHEAR IS ON THE WEAK SIDE BUT GIVEN DECENT INSTABILITY SOME STRONG UPDRAFTS COULD DEVELOP. PRECIPITABLE WATER VALUES INCREASE TO AROUND 1.6 INCHES AND STORM MOTION WILL BE ON THE SLOW SIDE SO ISOLATED AREAS OF HEAVY RAINFALL WOULD BE A PRIMARY CONCERN FOLLOWED BY STRONG GUSTY WINDS. HIGHS TODAY WILL RANGE FROM THE MID TO UPPER 80S WITH HIGHER LEVEL CLOUD COVER INCREASING THROUGH THE DAY AND BEING REINFORCED BY ANY CONVECTIVE ACTIVITY THIS AFTERNOON. SOUTHWEST WINDS WILL BE STRONG ENOUGH TO KEEP LAKEFRONT AREAS AS WARM AS INLAND AREAS. ATTENTION THEN TURNS TO THE COLD FRONT TO THE NORTHWEST WHICH WILL BE MAKING SLOW SOUTHEAST PROGRESS. LATEST TRENDS AND GUIDANCE SHOW A SLOWER PROGRESSION INTO THE AREA LATER TODAY. CURRENT CONVECTION ASSOCIATED WITH THE FRONT AND THE ASSOCIATED UPPER WAVES THAT ARE TRACKING EAST TO NORTHEAST ON THE PERIPHERY OF THE LARGER SCALE UPPER TROUGH BUILDING IN IS EXPECTED TO WEAKEN THIS MORNING. CONVECTION SHOULD BE RENEWED THIS AFTERNOON ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN AND WITH THE SLOWER TREND BEING EXHIBITED WOULD NOT MAKE IT INTO THE NORTHWEST CWA UNTIL AROUND OR AFTER 00Z. ISOLATED DEVELOPMENT COULD STILL OCCUR OUT AHEAD OF THE FRONT THANKS TO THE DEPARTING WAVE MENTIONED ABOVE AS WELL AS LARGER SCALE HEIGHT FALLS SPREADING IN FROM THE NORTHWEST. STORMS MAY REMAIN STRONG AS THEY WORK INTO THE NORTHWEST CWA BUT THE LATER ARRIVAL WOULD SUPPORT A LOWER THREAT...BUT WILL STILL NEED TO MONITOR THE CHANCE FOR STRONG WIND GUSTS AS WELL AS HEAVY RAINFALL. ACTIVITY WILL THEN GRADUALLY SPREAD SOUTHEASTWARD BUT MAY LOSE INTENSITY/COVERAGE AS IT DOES SO SO SOUTHEAST AREAS MAY SEE LITTLE ACTIVITY INTO THE OVERNIGHT. BY TUESDAY...THE BRITISH COLUMBIA WAVE WILL HAVE AMPLIFIED RESULTING IN A DEEPENING LONGWAVE TROUGH SWINGING INTO THE HIGH PLAINS. SURFACE LOW DEVELOPMENT WILL BE UNDERWAY ACROSS THE CENTRAL HIGH PLAINS BY TUESDAY MORNING. THE COOL FRONTAL BOUNDARY WHICH WILL MOVE INTO THE LOCAL AREA THIS EVENING WILL HAVE STALLED OUT AND MORPHED INTO A WARM FRONTAL BOUNDARY THANKS TO THE QUICKLY STRENGTHENING LOW DEVELOPMENT TO THE WEST. THIS WILL SET UP A MODEST WARM ADVECTION REGIME ALOFT OF THE AREA WHICH MAY FAVOR NEW SHOWER AND THUNDERSTORM DEVELOPMENT EARLY. THE SURFACE LOW WILL RAPIDLY DEEPEN AS IT MOVES NORTHEAST ACROSS NORTHWEST IOWA AND INTO THE UPPER MISSISSIPPI RIVER VALLEY TUESDAY EVENING...LIKELY FALLING BELOW 1000 MB BY LATE EVENING. TIMING OF ARRIVAL FOR THE BEST FORCING IS STILL IN QUESTION WITH LATEST GUIDANCE SUPPORTING A LATE AFTERNOON ARRIVAL IN THE FAR WEST WITH AN EASTWARD MOVEMENT ACROSS THE AREA THROUGH THE EVENING. DIURNALLY...THIS WOULD BE MORE FAVORABLE FOR STRONG/SEVERE THREAT BUT DEEP LAYER SHEAR IS STILL ON THE WEAK SIDE BUT DOES INTENSIFY THROUGH THE EVENING. WITH THE LOW LIFTING NORTHEAST THE FRONT WILL BE ORIENTED FAIRLY PARALLEL TO THE MID/UPPER LEVEL FLOW SO EASTWARD PROGRESSION OF STORM ACTIVITY WILL PROBABLY BE SLOW. COMBINE THIS WITH PRECIPITABLE WATER VALUES OF 1.8 TO 2 INCHES HEAVY RAIN BECOMES A CONCERN. CONFIDENCE IN THE OVERALL PATTERN PROGRESSION IS GOOD BUT THE DETAILS INCLUDING TIMING AND COVERAGE OF STORMS...AS WELL AS THE SEVERE POTENTIAL ARE LESS CERTAIN. WEDNESDAY...THE LOW WILL CONTINUE NORTHEAST WHILE DEEPENING A LITTLE FURTHER WEDNESDAY MORNING AS THE PRIMARY UPPER TROUGH AXIS SWINGS ACROSS THE AREA. IT APPEARS AS THOUGH CONVECTION WILL BE WORKING EAST ACROSS THE EASTERN CWA FIRST THING IN THE MORNING WITH A SECONDARY CHANCE LATER IN THE DAY AS THE UPPER TROUGH PASSES. COOLER MID LEVEL AIR WILL SPREAD IN SO HIGHS WILL BE NOTICEABLY COOLER WITH MID 70S NORTHWEST TO AROUND 80 SOUTHEAST. MDB && .LONG TERM... 258 AM CDT THURSDAY THROUGH SUNDAY... HIGH PRESSURE WILL BE ACROSS MUCH OF THE REGION THURSDAY AS THE UPPER FLOW PATTERN STARTS TO DE-AMPLIFY. HIGHS WILL PROBABLY BE HELD INTO THE 70S BUT A WARMING TREND WILL BE UNDERWAY FRIDAY. GULF MOISTURE BEGINS TO RETURN FRIDAY WITH A MORE ACTIVE SOUTHWESTERLY UPPER FLOW PATTERN SETTING UP SO SUBTLE WAVES COULD TRIGGER SOME ISOLATED CONVECTION SATURDAY. THERE IS GENERAL AGREEMENT IN ANOTHER UPPER TROUGH MOVING ACROSS THE NORTHERN PLAINS/UPPER GREAT LAKES SUNDAY BRINGING ANOTHER FRONT ACROSS THE AREA ALONG WITH CHANCES FOR SHOWERS AND THUNDERSTORMS. MDB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * TSRA POPPING A BIT FASTER THAN ANTICIPATED...BUT STILL WIDELY SCATTERED AS OF EARLY AFTERNOON. * TSRA COVERAGE FOR REMAINDER OF AFTERNOON...WITH A BREAK EXPECTED BY EVENING. * MORE TSRA WITH FRONTAL ZONE TONIGHT. * CIG/VSBYS TRENDS TONIGHT ALONG AND BEHIND FRONT. LENNING //DISCUSSION...UPDATED 18Z... A CHALLENGING FORECAST THIS AFTERNOON WITH WIDELY SCATTERED POCKETS OF TSRA AND NO SPECIFIC FOCUS TO HELP PIN DOWN TIMING AND LOCATIONS. COORDINATED WITH CWSU AND OPTED TO START WITH VCTS AND TEMPO TSRA EARLIER THAN PREVIOUS THINKING. SO FAR THE ARRIVALS AND DEPARTURES HAVE BEEN MORE OF A CONCERN THAN ACTIVITY AT TERMINALS. EXPECT THAT TSRA WILL BRIEFLY IMPACT TERMINALS FROM TIME TO TIME THIS AFTERNOON...BUT TRAFFIC RATES MAY BE LOW ENOUGH TO MITIGATE LONG DELAYS. THE DEMAND INCREASES AROUND 00 UTC BUT CONTRARY TO EARLIER THINKING...THIS MAY BE TOWARD THE END OF THE MORE WIDESPREAD CONVECTIVE PERIOD. ADDITIONAL TSRA IS POSSIBLE ALONG AN APPROACHING COLD FRONT TONIGHT...BUT TIMING MAY BE WELL AFTER THE PEAK TRAFFIC PERIOD FOR EITHER TERMINAL. LAST QUESTION PERTAINS TO CIG/VSBY TRENDS OVERNIGHT AFTER PERIODS OF RAINFALL. TOO LITTLE CONFIDENCE TO GET SPECIFIC AT THIS POINT...BUT THIS BEARS WATCHING. LENNING //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM TO HIGH CONFIDENCE ON SW WINDS TODAY EXCEPT NEAR TSRA. * LOW CONFIDENCE ON LOCATION OF AFTERNOON TSRA...AND MEDIUM CONFIDENCE ON TIMING. * MEDIUM CONFIDENCE ON TIMING AND COVERAGE OF TSRA TONIGHT. * LOW CONFIDENCE ON CIG/VSBY TRENDS OVERNIGHT. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...THUNDERSTORMS LIKELY. MVFR/IFR PSBL. SOUTH WINDS WEDNESDAY...CHC THUNDERSTORMS. MVFR PSBL. SOUTHWEST WINDS. THURSDAY...VFR. SOUTHWEST WINDS. FRIDAY...VFR. SOUTH WINDS. SATURDAY...VFR. SOUTH WINDS. SUNDAY...CHC THUNDERSTORMS. MVFR/IFR PSBL. SOUTHWEST WINDS. BMD && .MARINE... 315 AM CDT A SLOW MOVING COLD FRONT WILL GRADUALLY SAG SOUTH ACROSS LAKE MICHIGAN THROUGH THE DAY WITH SOUTH TO SOUTHWEST WINDS AHEAD OF THE FRONT AND NORTH TO NORTHEAST WINDS BEHIND. THE FRONT WILL BE THE FOCUS FOR THUNDERSTORM ACTIVITY THIS AFTERNOON AND EVENING. A DEEPENING LOW IS PROGGED TO LIFT FROM THE CENTRAL PLAINS INTO WISCONSIN BY TUESDAY NIGHT LIFTING THE FRONT BACK NORTH ACROSS THE LAKE WITH SOUTH TO SOUTHEAST WINDS OVERSPREADING THE LAKE. WINDS ARE EXPECTED TO VEER TO THE SOUTHWEST AND RAMP UP THROUGH THE DAY WEDNESDAY INTO WEDNESDAY NIGHT. THERE IS CONSIDERABLE SPREAD ON THE STRENGTH OF THE LOW BETWEEN DIFFERENT MODELS RESULTING IN UNCERTAINTY IN HOW STRONG THE WINDS WILL BECOME...SO STAY TUNED FOR UPDATES AS THE EVENT COMES INTO BETTER FOCUS...BUT FOR NOW ONLY BROUGHT WINDS UP TO 30KT WEDNESDAY NIGHT. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && 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 NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 1152 AM CDT MON AUG 17 2015 ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019- 181700- 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- 1152 AM CDT MON AUG 17 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL ILLINOIS... NORTHEAST ILLINOIS AND NORTHWEST INDIANA. .DAY ONE...TODAY AND TONIGHT. WEATHER HAZARDS EXPECTED: SCATTERED THUNDERSTORMS...THE STRONGEST OF WHICH MAY PRODUCE: WIND GUSTS OF 50-60 MPH FREQUENT LIGHTNING HEAVY DOWNPOURS AREAS AFFECTED AND TIMING: MUCH OF NORTHERN ILLINOIS AND NORTHWEST INDIANA THIS AFTERNOON AND EVENING. DISCUSSION: THE OUTLOOK AREA WILL BE POSITIONED BETWEEN AN UPPER LEVEL TROUGH MOVING NORTH-NORTHEAST FROM THE LOWER OHIO RIVER VALLEY AND A COLD FRONT SLOWLY APPROACHING FROM THE NORTHWEST. FORCING FROM THESE FEATURES WILL COMBINE WITH AN UNSTABLE AIRMASS TO GENERATE SCATTERED THUNDERSTORMS THIS AFTERNOON. A MORE CONCENTRATED AREA OF THUNDERSTORMS IS EXPECTED TO MOVE INTO NORTH- CENTRAL ILLINOIS LATE THIS AFTERNOON OR EARLY THIS EVENING AS THE COLD FRONT ARRIVES. THIS ACTIVITY WILL MOVE EASTWARD THROUGH THE EVENING BUT LIKELY DIMINISH IN COVERAGE AND INTENSITY WITH TIME. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY. THERE ARE PERIODIC CHANCES FOR THUNDERSTORMS TUESDAY THROUGH WEDNESDAY...AND AGAIN ON SATURDAY. A FEW OF THE THUNDERSTORMS TUESDAY AND WEDNESDAY COULD BECOME STRONG TO SEVERE AND PRODUCE HEAVY DOWNPOURS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT...HOWEVER ANY REPORTS OF SIGNIFICANT WIND...HAIL OR RAINFALL FROM ANY STRONG STORMS THIS AFTERNOON AND THIS EVENING ARE WELCOMED. && LMZ740>745-181700- 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- 1152 AM CDT MON AUG 17 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE ILLINOIS NEARSHORE WATERS OF LAKE MICHIGAN AND THE INDIANA NEARSHORE WATERS OF LAKE MICHIGAN. .DAY ONE...TODAY AND TONIGHT. ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE THROUGH TONIGHT. THE STRONGEST STORMS MAY PRODUCE GUSTY WINDS AND HEAVY DOWNPOURS. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY. THERE ARE PERIODIC CHANCES FOR THUNDERSTORMS TUESDAY AND WEDNESDAY AND AGAIN ON SATURDAY. && LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868- 870-872-874-876-878-181700- 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- 1152 AM CDT MON AUG 17 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE OPEN WATERS OF LAKE MICHIGAN. .DAY ONE...TODAY AND TONIGHT. ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE THROUGH TONIGHT. THE STRONGEST STORMS MAY PRODUCE GUSTY WINDS AND HEAVY DOWNPOURS ACROSS FAR SOUTHERN LAKE MICHIGAN. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY. THERE ARE PERIODIC CHANCES FOR THUNDERSTORMS TUESDAY AND WEDNESDAY AND AGAIN ON SATURDAY. && KMD 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
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 225 PM CDT MON AUG 17 2015 ILZ020>022-171945- WILL IL-KENDALL IL-GRUNDY IL- 225 PM CDT MON AUG 17 2015 ...SPECIAL WEATHER STATEMENT FOR WEST CENTRAL WILL...SOUTHEASTERN KENDALL AND NORTHEASTERN GRUNDY COUNTIES UNTIL 245 PM CDT... AT 223 PM CDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM OVER SHOREWOOD...OR NEAR MINOOKA...MOVING NORTHEAST AT 10 MPH. NICKEL SIZE HAIL AND OCCASIONALY NEAR QUARTER SIZE...AND WINDS IN EXCESS OF 30 MPH WILL BE POSSIBLE WITH THIS STORM...ALONG WITH VERY HEAVY RAIN. LOCATIONS IMPACTED INCLUDE... JOLIET... ROMEOVILLE... PLAINFIELD... NEW LENOX... CHANNAHON... MINOOKA... INGALLS PARK... SHOREWOOD... ELWOOD... ROCKDALE... CREST HILL... PRESTON HEIGHTS... CRYSTAL LAWNS... INCLUDING THE FOLLOWING INTERSTATES... I-55 BETWEEN MILE MARKERS 246 AND 260. I-80 BETWEEN MILE MARKERS 119 AND 135. THIS INCLUDES... UNIVERSITY OF ST. FRANCIS...CHANNAHON STATE PARK...CHICAGOLAND SPEEDWAY ROUTE 66 RACEWAY...JOLIET JUNIOR COLLEGE...AND JOLIET SLAMMERS BASEBALL. LAT...LON 4139 8826 4153 8841 4166 8821 4148 8799 TIME...MOT...LOC 1923Z 227DEG 7KT 4151 8824 LENNING
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
239 PM CDT MON AUG 17 2015
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0237 PM HAIL CEDAR LAKE 41.37N 87.44W
08/17/2015 M0.25 INCH LAKE IN TRAINED SPOTTER
HAIL LASTED 2 TO 3 MINUTES.
&&
ACSThe Chicago radar (KLOT), 16 km away, was scanning. The volume nearest the first event began at 19:41 UTC.
2 thunderstorm wind, 1 lightning, 1 flash flood. Local standard time, as filed.
A 14 to 16 inch diameter tree was snapped in the Wesmere Lakes subdivision. A large tree limb was blown down near Townsend Boulevard and Southworth Circle.
A four to six inch diameter tree branch was snapped off.
Multiple utility poles were down due to lightning.
All lanes and shoulders on east bound I-290 at Des Plaines Avenue were flooded and closed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2015Every state in 2015This day in weather historyWarnings in Illinois, August 2015
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: 597627, 597636, 597637, 597644.