Severe Thunderstorm Watch 821

Issued

Jul 31, 2003, 5:40 PM CDT (22:40 UTC)

Expired

Jul 31, 2003, 11:00 PM CDT

In force

5 hr

Issued by

the Storm Prediction Center

The La Crosse radar (KARX), 48 km from the middle of the area, began a volume at 22:40 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.

• Mesoscale Discussion 2033Jul 31, 2:38 PM CDT
• Mesoscale Discussion 2035Jul 31, 5:07 PM CDT
• Mesoscale Discussion 2040Jul 31, 8:19 PM CDT

000 
WWUS20 KWNS 312237
SEL1  
SPC WW 312240
IAZ000-ILZ000-MNZ000-WIZ000-010400-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 821 
NWS STORM PREDICTION CENTER NORMAN OK 
540 PM CDT THU JUL 31 2003

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 

       NORTHEAST IOWA
       NORTHERN ILLINOIS
       SOUTHEAST MINNESOTA
       SOUTHERN AND CENTRAL WISCONSIN

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 540 PM UNTIL
1100 PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 95 STATUTE MILES
NORTH AND SOUTH OF A LINE FROM 30 MILES NORTHWEST OF WATERLOO IOWA
TO 35 MILES SOUTHEAST OF OSHKOSH WISCONSIN.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA.
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE
TORNADOES.


OTHER WATCH INFORMATION...CONTINUE...WW 817...WW 818...WW 820...WW
819...


DISCUSSION...SCATTERED SEVERE STORMS WILL PERSIST FOR THE NEXT FEW
HOURS ACROSS THE WATCH AREA.  SMALL AREAS OF ERN WI HAVE BEEN
STABILIZED BY EARLIER STORMS...BUT A CONTINUED FEED OF MODERATE
INSTABILITY FROM THE SW...AND THE APPROACH OF A MID LEVEL SHORTWAVE
TROUGH FROM MN...WILL SUPPORT A CONTINUED THREAT OF LARGE HAIL AND
DAMAGING WINDS.  ADDITIONALLY...DEEP LAYER SHEAR WILL BECOME
SUFFICIENT FOR SUPERCELLS INVOF NE IA/SW WI/NE IA...WHERE THE THREAT
FOR LARGE HAIL WILL BE ENHANCED.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 28020.


...THOMPSON

441,0924 450,0880 421,0880 412,0924 

WWUS20 KWNS 312237
SEL1  
SPC WW 312240
IAZ000-ILZ000-MNZ000-WIZ000-010400-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 821 
NWS STORM PREDICTION CENTER NORMAN OK 
540 PM CDT THU JUL 31 2003

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 

       NORTHEAST IOWA
       NORTHERN ILLINOIS
       SOUTHEAST MINNESOTA
       SOUTHERN AND CENTRAL WISCONSIN

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 540 PM UNTIL
1100 PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 95 STATUTE MILES
NORTH AND SOUTH OF A LINE FROM 30 MILES NORTHWEST OF WATERLOO IOWA
TO 35 MILES SOUTHEAST OF OSHKOSH WISCONSIN.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA.
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE
TORNADOES.


OTHER WATCH INFORMATION...CONTINUE...WW 817...WW 818...WW 820...WW
819...


DISCUSSION...SCATTERED SEVERE STORMS WILL PERSIST FOR THE NEXT FEW
HOURS ACROSS THE WATCH AREA.  SMALL AREAS OF ERN WI HAVE BEEN
STABILIZED BY EARLIER STORMS...BUT A CONTINUED FEED OF MODERATE
INSTABILITY FROM THE SW...AND THE APPROACH OF A MID LEVEL SHORTWAVE
TROUGH FROM MN...WILL SUPPORT A CONTINUED THREAT OF LARGE HAIL AND
DAMAGING WINDS.  ADDITIONALLY...DEEP LAYER SHEAR WILL BECOME
SUFFICIENT FOR SUPERCELLS INVOF NE IA/SW WI/NE IA...WHERE THE THREAT
FOR LARGE HAIL WILL BE ENHANCED.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 28020.


...THOMPSON

441,0924 450,0880 421,0880 412,0924

Severe Thunderstorm Watches in Wisconsin, 2003Severe Thunderstorm Watches in Iowa, 2003Severe Thunderstorm Watches in Illinois, 2003Every severe thunderstorm watch in 2003

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.