Seiche in Illinois, May 21, 2004

Name: Seiche in Illinois, May 21, 2004
Start: 2004-05-21T10:50
End: 2004-05-21T11:10
Location: Illinois

May 21, 2004 · NWS LOT · 1 event in 1 county or zone

1 seiche, as filed by the National Weather Service.

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 1

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

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Chicago, IL wrote its last area forecast discussion before the first event at May 21, 5:15 AM CST, 5 hours 35 minutes earlier.

Area forecast discussion, May 21, 5:15 AM CST, 5 hours 35 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO IL
615 AM CDT FRI MAY 21 2004

.DISCUSSION FOR MORNING ZONES/GRIDS:

HAVE DECIDED TO DROP FLOOD WATCH.  AREA IS NOW BETWEEN TWO LARGE
CONVECTIVE COMPLEXES...WITH MID/UPR LVL RIDGING IN BETWEEN.  OF
CONCERN IS THE GROWING MCS OVR NRN IA/SRN MN.  THE SPC SWODY1
DISCUSSION AS WELL AS ETA/MESOETA FCSTS ALL SUGGEST THIS COMPLEX
WILL MOVE ENEWD AND STAY MNLY IN WI.  WITH AREA NOW VOID OF ANY
TSTMS...AND FOCUS OF BEST THETA E CONVERGENCE EXPECTED TO BE N OF
SFC BOUNDARY WHICH WILL BE LIFTING NWD LATER THIS MORNING.  BASED ON
THESE REASONS...DECISED TO DROP THE WATCH.  HOWEVER...THIS DOESNT
MEAN WERE OUT OF THE WOODS.  MESO BOUNDARIES WILL SURELY BE
PRODUCED BY MCS EVEN IF IT DOES STAY JUST N OF FA.  AS FRONT
RETREATS NWD THIS MRNG AND LIFTS N OF FA ERLY THIS AFTN...AMS IS
AGAIN FCST TO BECOME VERY UNSTABLE WITH SB CAPES AOA 3000.  ANY
INTERACTION WITH RESIDUAL BOUNDARIES WILL LIKELY INITIATE NEW
CONVECTION.  THIS APPEARS MOST LIKELY TO OCCUR OVR NRN PORTION OF
FA.  IN ADDITION...HAVE DECIDED TO KEEP CHC POPS GOING OVR MUCH OF
RGN THRU TNGT DESPITE BEING S OF BEST LARGE SCALE FORCING AS ETA IS
PROGGING VORT TAIL...ASSD WITH SHORT WAVE NOW TRIGGING STMS TO NW OF
IL...TO MOVE INTO NWRN IL BY 00Z.   DONT WANT TO KEEP ISSUING FLOOD
WATCHES AD NAUSEAM DUE TO UNCERTAINTY ON DEGREE OF AREAL COVG WITH
TSTMS TDY AND TNGT.

TSTM CLUSTERS APPEAR MORE LIKELY LATE SAT AND SAT NGT AS AREA IS
FCST TO BE UNDER IMPRESSIVE LLJ AXIS WITH H85 WINDS FCST TO BE NR 50
KT AND DEWPOINTS EXPECTED AROUND 14 C.  AT THIS TIME...THIS LOOKS
LIKE MOST FVRBL PERIOD FOR MORE FLOOD POTL.

MORE SIG SYS TO MOVE THRU UPR MIDWEST LATE SUN/SUN NGT...AND THIS
SHUD BRING STRONGER PUSH OF COOLER...MORE STABLE AIR ACROSS FA.

BY SUN...GFS AND ETA GET QUITE DIVERGENT IN THEIR HANDLING OF SYS
LIFTING OUT OF PLAINS STAS.  WILL CONTINUE BASING FCST ON BETTER
INITIALIZED ETA...BUT WILL SLOW DOWN MOVEMENT OF THIS SYS WITH TIME
TO BLEND A BIT WITH GFS.

MERZLOCK

&&

.AVIATION...
FOR 12Z TAFS...SHALLOW WEDGE OF COOLER DRIER AIR SPREADING SE ACROSS
TERMINALS AS SFC HI BUILDS ESE INTO NRN GRTLKS FORMING ST AS MOIST
AIRMASS ALOFT IS CHILLED. CONT ADVECTION OF LOER DWPTS INTO AREA
WILL LIFT CIGS HIER INTO MVFR RANGE DURG FIRST PART OF
MORNING...THEN CIGS SHUD BREAKOUT BTWN SFC HEATING AND FRONTAL BNDRY
LIFTING BACK NWRD AROUND MIDDAY. SCT -SHRA RECENTLY DVLPG DVN-PIA
BUT RPDLY WEAKENING AND DO NOT EXPECT ANY SIG DVLPMNT DURG MORNING.
BEST CHC FOR TSRA MLATER AFTERNOON THRU ERLY EVE AS VORT CURRENTLY
MOVG NE ACROSS ERN KS AND NEB MOVS INTO NRN IL.

&&

.LOT...WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LK MI...NONE.

Hazardous weather outlook, May 21, 9:45 AM CST, 1 hour 5 minutes before

HAZARDOUS WEATHER OUTLOOK...CORRECTED FOR MARINE PORTION
NATIONAL WEATHER SERVICE CHICAGO IL
1045 AM CDT FRI MAY 21 2004

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-
019-221100-
BENTON-BOONE-COOK-DE KALB-DU PAGE-FORD-GRUNDY-IROQUOIS-JASPER-
KANE-KANKAKEE-KENDALL-LA SALLE-LAKE-LAKE IN-LEE-LIVINGSTON-
MCHENRY-NEWTON-OGLE-PORTER-WILL-WINNEBAGO-
1045 AM CDT FRI MAY 21 2004

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

.DAY ONE...TODAY AND TONIGHT

THROUGH EARLY AFTERNOON...SEVERE WEATHER IS NOT ANTICIPATED AS A
LINE OF THUNDERSTORMS HAS MOVED THROUGH MOST OF THE AREA...WHICH HAS
TEMPORARILY STABILIZED THE ATMOSPHERE. HOWEVER...NUMEROUS SEVERE
THUNDERSTORMS ARE ANTICIPATED TO REDEVELOP IN AREAS WEST OF
INTERSTATE 39 AFTER 2 PM...AND FOR AREAS EAST OF INTERSTATE 39 AFTER
4 PM.  THE SEVERE THREAT WILL CONTINUE UNTIL AT LEAST MIDNIGHT
TONIGHT.

THE MAIN THREATS WILL BE STRAIGHT LINE WIND GUSTS ABOVE 60
MPH...HAIL THAT IS NICKEL SIZE OR LARGER...AND VERY HEAVY RAIN
PRODUCING FLASH FLOODING IN A VERY SHORT TIME FRAME. IN ADDITION...
THERE IS A RISK OF A FEW TORNADOES.

AS A RESULT...A MODERATE RISK OF SEVERE THUNDERSTORMS IS IN EFFECT
FOR MOST OF THE AREA.

A FRONTAL BOUNDARY FROM NEAR DAVENPORT IOWA TO PONTIAC ILLINOIS TO
VALPARAISO INDIANA...WILL RETURN NORTHWARD AS A WARM FRONT THIS
AFTERNOON. THIS FRONT WILL SEPARATE RELATIVELY COOL AIR TO THE NORTH
FROM WARM AND HUMID AIR TO THE SOUTH. THE MAIN FOCUS FOR
THUNDERSTORM DEVELOPMENT WILL BE NEAR AND SOUTH OF THE FRONT. IN
ADDITION...THE GREATEST POTENTIAL FOR TORNADIC THUNDERSTORMS WILL BE
NEAR THE FRONTAL BOUNDARY.

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

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS AGAIN SATURDAY AND
SATURDAY NIGHT.  IN ADDITION...A HEAVY RAINFALL POTENTIAL ALSO
EXISTS FOR SATURDAY AFTERNOON AND SATURDAY NIGHT.

THUNDERSTORMS MAY CONTINUE THROUGH SUNDAY...BEFORE A COLD FRONT
PUSHES TROUGH THE MIDWEST AND TEMPORARILY ENDS THE STORM THREAT.

THUNDERSTORMS ARE POSSIBLE AGAIN LATE MONDAY NIGHT AND TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BECOME NECESSARY TONIGHT.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE
NWS CHICAGO WEBPAGE: WWW.CRH.NOAA.GOV/LOT (LOWER CASE)

LMZ740>746-766-221100-
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-MICHIGAN CITY
TO NEW BUFFALO-LAKE MICHIGAN-
1045 AM CDT FRI MAY 21 2004

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

.DAY ONE...TODAY AND TONIGHT

A LINE OF SEVERE THUNDERSTORMS HAVE MOVED ACROSS THE WESTERN HALF OF
LAKE MICHIGAN...AND WILL AFFECT THE EASTERN HALF OF THE LAKE THROUGH
1 PM.  NUMEROUS SEVERE THUNDERSTORMS WILL REDEVELOP ACROSS IOWA AND
ILLINOIS AFTER 4 PM...AND AFFECT LAKE MICHIGAN PRIMARILY BETWEEN 4
PM AND MIDNIGHT.  THE MAIN THREATS WILL BE WINDS OVER 50
KNOTS...LARGE HAIL...HIGH WAVES AND FREQUENT CLOUD TO GROUND
LIGHTNING. THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER THE
ENTIRE AREA.

A FRONTAL BOUNDARY EXTENDING FROM CENTRAL IOWA TO NORTHERN INDIANA
WILL RETURN NORTHWARD AS A WARM FRONT TODAY.  THIS FRONT WILL
SEPARATE RELATIVELY COOL AIR TO THE NORTH FROM WARM AND STICKY AIR
TO THE SOUTH.  THE MAIN FOCUS FOR THUNDERSTORM DEVELOPMENT WILL BE
TO THE NORTH OF THIS FRONT.  HOWEVER...NUMEROUS THUNDERSTORMS WILL
LIKELY DEVELOP LATE THIS AFTERNOON AND TONIGHT...IN THE UNSTABLE AIR
ALONG AND JUST SOUTH OF THIS BOUNDARY AS WELL.

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

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS AGAIN SATURDAY AND
SATURDAY NIGHT.  IN ADDITION...A HEAVY RAINFALL POTENTIAL ALSO
EXISTS FOR SATURDAY AFTERNOON AND SATURDAY NIGHT.

THUNDERSTORMS MAY CONTINUE THROUGH SUNDAY...BEFORE A COLD FRONT
PUSHES TROUGH THE MIDWEST AND TEMPORARILY ENDS THE STORM THREAT.

THUNDERSTORMS ARE POSSIBLE AGAIN LATE MONDAY NIGHT AND TUESDAY.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE
NWS CHICAGO WEBPAGE: WWW.CRH.NOAA.GOV/LOT (LOWER CASE)

STEFKOVICH/PIETRYCHA

In the hours before

Local storm report, May 21, 10:15 AM CST, 35 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
1115 AM CDT FRI MAY 21 2004

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

1009 AM     TSTM WND DMG     MELROSE PARK            41.90N 87.86W
05/21/2004                   COOK               IL   EMERGENCY MNGR

            8 TO 10 INCH DIAMETER TREE LIMBS DOWN. STADIUM LIGHTS
            DAMAGED AT CIVIC CENTER. MOST OF DAMAGE ALONG CHICAGO
            AVENUE.

&&

SMITTY

Local storm report, May 21, 10:33 AM CST, 17 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
1133 AM CDT FRI MAY 21 2004

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

1040 AM     MARINE TSTM WIND MICHIGAN CITY           41.71N 86.88W
05/21/2004  47 MPH           LA PORTE           IN   OFFICIAL NWS OBS

            MEASURED AT MICHIGAN CITY CRIB

&&

ACS

Local storm report, May 21, 10:35 AM CST, 15 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
1135 AM CDT FRI MAY 21 2004

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

1005 AM     MARINE TSTM WIND CHICAGO                 41.88N 87.63W
05/21/2004  52 MPH           COOK               IL   OFFICIAL NWS OBS

            MEASURED AT CHICAGO CRIB

&&

ACS

Local storm report, May 21, 10:38 AM CST, 12 minutes before

PRELIMINARY LOCAL STORM REPORT ... CORRECTION
NATIONAL WEATHER SERVICE CHICAGO IL
1138 AM CDT FRI MAY 21 2004

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

0950 AM     TSTM WND DMG     5 SE LAKE ZURICH        42.14N 88.02W
05/21/2004                   COOK               IL   TRAINED SPOTTER

            TREE AND LARGE BRANCHES DOWN.

&&

ACS

Local storm report, May 21, 10:42 AM CST, 8 minutes before

PRELIMINARY LOCAL STORM REPORT ... SUMMARY
NATIONAL WEATHER SERVICE CHICAGO IL
1142 AM CDT FRI MAY 21 2004

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

1040 AM     MARINE TSTM WIND MICHIGAN CITY           41.71N 86.88W
05/21/2004  47 MPH           LA PORTE           IN   OFFICIAL NWS OBS

            MEASURED AT MICHIGAN CITY CRIB

1025 AM     TSTM WND DMG     HINSDALE                41.80N 87.93W
05/21/2004                   DUPAGE             IL   PUBLIC

            LARGE TREE LIMBS DOWN.

1015 AM     TSTM WND DMG     EVANSTON                42.05N 87.69W
05/21/2004                   COOK               IL   TRAINED SPOTTER

            TREE BRANCHES DOWN AT CORNER OF SHERMAN AND MAIN.

1015 AM     TSTM WND DMG     WEST CHICAGO            41.89N 88.22W
05/21/2004                   DUPAGE             IL   EMERGENCY MNGR

            WIDESPREAD LARGE TREES AND POWER LINES DOWN ACROSS MUCH
            OF DONWTOWN AREA.

1009 AM     TSTM WND DMG     MELROSE PARK            41.90N 87.86W
05/21/2004                   COOK               IL   EMERGENCY MNGR

            8 TO 10 INCH DIAMETER TREE LIMBS DOWN. STADIUM LIGHTS
            DAMAGED AT CIVIC CENTER. MOST OF DAMAGE ALONG CHICAGO
            AVENUE.

1005 AM     MARINE TSTM WIND CHICAGO                 41.88N 87.63W
05/21/2004  52 MPH           COOK               IL   OFFICIAL NWS OBS

            MEASURED AT CHICAGO CRIB

1005 AM     HAIL             DES PLAINES             42.03N 87.90W
05/21/2004  0.75 INCH        COOK               IL   TRAINED SPOTTER

1005 AM     MARINE TSTM WIND CHICAGO                 41.88N 87.63W
05/21/2004  52 MPH           COOK               IL   OFFICIAL NWS OBS

            MEASURED AT CHICAGO CRIB

0958 AM     HAIL             SCHAUMBURG              42.03N 88.08W
05/21/2004  0.75 INCH        COOK               IL   PUBLIC

0955 AM     TSTM WND GST     DES PLAINES             42.03N 87.90W
05/21/2004  60 MPH           COOK               IL   AMATEUR RADIO

0955 AM     TSTM WND DMG     HAWTHORN WOODS          42.22N 88.06W
05/21/2004                   LAKE               IL   AMATEUR RADIO

            TREES AND POWER LINES DOWN.

0950 AM     TSTM WND DMG     5 SE LAKE ZURICH        42.14N 88.02W
05/21/2004                   COOK               IL   TRAINED SPOTTER

            TREE AND LARGE BRANCHES DOWN.

0944 AM     TSTM WND DMG     CARPENTERSVILLE         42.12N 88.27W
05/21/2004                   KANE               IL   TRAINED SPOTTER

            TREE BRANCHES DOWN.

0944 AM     HAIL             CARPENTERSVILLE         42.12N 88.27W
05/21/2004  0.75 INCH        KANE               IL   TRAINED SPOTTER

0940 AM     TSTM WND DMG     HAMPSHIRE               42.10N 88.52W
05/21/2004                   KANE               IL   EMERGENCY MNGR

            SOME TREES AND POWER LINES DOWN WITH REPORTS OF TWO SEMI
            TRACTOR TRAILERS BLOWN OFF ROAD IN PORTIONS OF NORTHERN
            KANE COUNTY.

0935 AM     TSTM WND DMG     ANTIOCH                 42.47N 88.08W
05/21/2004                   LAKE               IL   TRAINED SPOTTER

            TREES AND POWER LINES DOWN.

0910 AM     TSTM WND GST     BELVIDERE               42.25N 88.85W
05/21/2004  60 MPH           BOONE              IL   AMATEUR RADIO

            GTREE BRANCHES DOWN.

&&

ACS

Local storm report, May 21, 10:50 AM CST, 0 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
1150 AM CDT FRI MAY 21 2004

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

0900 AM     TSTM WND DMG     LOVES PARK              42.34N 89.01W
05/21/2004                   WINNEBAGO          IL   LAW ENFORCEMENT

            7 INCH DIAMETER TREE LIMBS DOWN BETWEEN HARLEM AND WINDSO
            ROADS.

&&

ACS

Event by event

1 seiche. Local standard time, as filed.

Seiche, Cook

When: May 21, 10:50 AM CST to 11:10 AM CST
Where: Cook forecast zone
Reported by: BROADCAST MEDIA

Belmont Harbor and Calumet Harbor reported a 3 to 4 foot seiche.

What these are

Seiche: A standing wave in a lake or bay, pushed by wind or pressure, that flooded the shore.

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

The same day elsewhere

Every storm in Illinois in 2004 Every state in 2004 This day in weather history Warnings in Illinois, May 2004

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5397374.