Tornado Watch 479

Issued

Jul 3, 2007, 3:59 PM CDT (20:59 UTC)

Expired

Jul 4, 2007, 12:00 AM CDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

2.5 in

Strongest gust expected

60 kt

The Sioux Falls radar (KFSD), 107 km from the middle of the area, began a volume at 21:00 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.

Two or more tornadoes

40%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

50%

One or more gusts of 65 knots or more

20%

Ten or more severe hail reports

60%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 1369Jul 3, 3:36 PM CDT
• Mesoscale Discussion 1372Jul 3, 6:55 PM CDT
• Mesoscale Discussion 1375Jul 3, 10:24 PM CDT

000
WWUS20 KWNS 032100
SEL9  
SPC WW 032100
IAZ000-MNZ000-NEZ000-SDZ000-040500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 479
NWS STORM PREDICTION CENTER NORMAN OK
400 PM CDT TUE JUL 3 2007

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

       NORTHWEST AND NORTH CENTRAL IOWA
       SOUTHWEST MINNESOTA
       NORTHEAST NEBRASKA
       SOUTHEAST SOUTH DAKOTA

EFFECTIVE THIS TUESDAY AFTERNOON FROM 400 PM UNTIL MIDNIGHT CDT.

TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 45 MILES WEST OF NORFOLK
NEBRASKA TO 20 MILES NORTHEAST OF MASON CITY IOWA.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU9).

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 477...WW 478...

DISCUSSION...TSTMS/POSSIBLE SUPERCELLS EXPECTED TO DEVELOP IN THE
NEXT 1-2 HRS AS HEATING CONTINUES INVOF SE-MOVING FRONT.  RICH
MOISTURE INFLOW AND STEEP MID LEVEL LAPSE RATES ARE CONTRIBUTING TO
SUBSTANTIAL CAPE AND POTENTIALLY LOW CLOUD BASES.  THIS MAY SUPPORT
A THREAT FOR A COUPLE TORNADOES...DESPITE MODEST LOW LVL
SHEAR...BEFORE ACTIVITY EVOLVES INTO A CLUSTER WITH A CONTINUING
THREAT FOR LARGE HAIL/WIND.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 29025.


...CORFIDI

Tornado Watches in Iowa, 2007Tornado Watches in Nebraska, 2007Tornado Watches in South Dakota, 2007Every tornado watch in 2007

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.