Tornado Watch 698

Issued

Sep 30, 2007, 1:02 PM CDT (18:02 UTC)

Expired

Sep 30, 2007, 8:00 PM CDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

1.5 in

Strongest gust expected

70 kt

The Omaha radar (KOAX), 18 km from the middle of the area, began a volume at 18:03 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

50%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

60%

One or more gusts of 65 knots or more

60%

Ten or more severe hail reports

40%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

80%

• Mesoscale Discussion 2040Sep 30, 10:13 AM CDT
• Mesoscale Discussion 2041Sep 30, 11:01 AM CDT
• Mesoscale Discussion 2042Sep 30, 12:10 PM CDT
• Mesoscale Discussion 2044Sep 30, 2:26 PM CDT
• Mesoscale Discussion 2045Sep 30, 3:36 PM CDT
• Mesoscale Discussion 2046Sep 30, 5:45 PM CDT

000
WWUS20 KWNS 301807
SEL8  
SPC WW 301807
IAZ000-NEZ000-SDZ000-010100-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 698
NWS STORM PREDICTION CENTER NORMAN OK
105 PM CDT SUN SEP 30 2007

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

       WESTERN IOWA
       EASTERN NEBRASKA
       EXTREME SOUTHEAST SOUTH DAKOTA

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 105 PM UNTIL 800
PM CDT.

TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 90 STATUTE
MILES EAST AND WEST OF A LINE FROM 15 MILES SOUTH SOUTHWEST OF
BEATRICE NEBRASKA TO 20 MILES NORTH OF SPENCER IOWA.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU8).

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 697...

DISCUSSION...POTENT MID-LEVEL DISTURBANCE AND ASSOCIATED DEVELOPING
SURFACE LOW OVER NEBRASKA WILL DEVELOP ENEWD ACROSS THE MISSOURI
RIVER VALLEY TO NWRN/CNTRL IA THROUGH THE AFTERNOON/EARLY EVENING.
DESPITE ONLY WEAK DESTABILIZATION...INCREASINGLY STRONG DYNAMIC
FORCING FOR ASCENT AND INTENSE WIND FIELDS AND SHEAR ARE EXPECTED TO
SUPPORT THE DEVELOPMENT OF STRONG TO SEVERE STORMS/SUPERCELLS. GIVEN
STRENGTH OF EFFECTIVE SHEAR AND LOW LEVEL HODOGRAPH TURNING WITHIN
AND NEAR THE DEVELOPING LOW...A FEW TORNADOES ARE
POSSIBLE...ESPECIALLY EARLY IN THE DEVELOPMENT CYCLE. FAST
TRANSLATION TO THE ENTIRE LAGER-SCALE SYSTEM SHOULD PROMOTE
BAND/LINES OF STORMS WITH TIME. THIS ACTIVITY WILL RACE EWD WITH
DAMAGING WINDS AND ISOLATED TORNADO POTENTIAL SPREADING INTO CNTRL
IA BY EARLY EVENING.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
450. MEAN STORM MOTION VECTOR 23045.


...CARBIN

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.