Tornado Watch 778

Issued

Jul 20, 2003, 8:30 PM CDT (01:30 UTC)

Expired

Jul 21, 2003, 2:00 AM CDT

In force

6 hr

Issued by

the Storm Prediction Center

The Des Moines radar (KDMX), 136 km from the middle of the area, began a volume at 01:31 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 1918Jul 20, 5:29 PM CDT
• Mesoscale Discussion 1924Jul 20, 8:08 PM CDT
• Mesoscale Discussion 1929Jul 20, 11:14 PM CDT

000 
WWUS20 KWNS 210131
SEL8  
SPC WW 210130
IAZ000-ILZ000-WIZ000-210700-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 778 
NWS STORM PREDICTION CENTER NORMAN OK 
830 PM CDT SUN JUL 20 2003

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

       EASTERN IOWA
       NORTHWEST ILLINOIS
       SOUTHWEST WISCONSIN

EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 830 PM UNTIL
200 AM CDT.

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

THE TORNADO WATCH AREA IS ALONG AND 85 STATUTE MILES NORTH AND
SOUTH OF A LINE FROM 15 MILES NORTHWEST OF DES MOINES IOWA TO 50
MILES EAST OF DUBUQUE IOWA.

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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.


OTHER WATCH INFORMATION...CONTINUE...WW 772...WW 773...WW 775...WW
776...WW 777...


DISCUSSION...THUNDERSTORMS ARE RAPIDLY INTENSIFYING ALONG SURFACE
BOUNDARY OVER NORTHEAST IA.  THIS ACTIVITY IS EXPECTED TO BECOME
SEVERE AND TRACK EASTWARD INTO SOUTHWEST WI AND NORTHWEST IL. 
SUPERCELLS ARE POSSIBLE...WITH SOME THREAT OF TORNADOES IN THE NEXT
FEW HOURS.  PRIMARY THREAT IS EXPECTED TO BE LARGE HAIL AND DAMAGING
WINDS.

AVIATION...TORNADOES AND 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 30035.


...HART

425,0935 433,0894 410,0894 402,0935

Tornado Watches in Iowa, 2003Tornado Watches in Illinois, 2003Tornado Watches in Wisconsin, 2003Every tornado 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.