Tornado Watch 613

Issued

Aug 17, 2007, 4:21 PM MDT (22:21 UTC)

Expired

Aug 18, 2007, 12:00 AM MDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

3 in

Strongest gust expected

60 kt

The Rapid City radar (KUDX), 54 km from the middle of the area, began a volume at 22:21 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

50%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 1782Aug 17, 3:47 PM MDT
• Mesoscale Discussion 1788Aug 17, 8:39 PM MDT

000
WWUS20 KWNS 172223
SEL3  
SPC WW 172223
MTZ000-SDZ000-WYZ000-180600-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 613
NWS STORM PREDICTION CENTER NORMAN OK
520 PM CDT FRI AUG 17 2007

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

       FAR SOUTHEAST MONTANA
       WESTERN AND SOUTH CENTRAL SOUTH DAKOTA
       NORTHEAST WYOMING

EFFECTIVE THIS FRIDAY AFTERNOON AND SATURDAY MORNING FROM 520 PM
UNTIL 100 AM CDT.

TORNADOES...HAIL TO 3 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 105 STATUTE
MILES EAST AND WEST OF A LINE FROM 105 MILES NORTH OF RAPID CITY
SOUTH DAKOTA TO 75 MILES SOUTH SOUTHWEST OF PHILIP SOUTH DAKOTA. 
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU3).

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 612...

DISCUSSION...TSTMS/SUPERCELLS EXPECTED TO POSE A THREAT FOR LARGE
HAIL/HIGH WIND AND POSSIBLE TORNADOES IN WRN SD AND POSSIBLY
ADJACENT AREAS OF WY FAR SE MT THIS EVENING AS HEATING AND LOW LVL
MOISTURE INFLOW CONTINUE AHEAD OF APPROACHING UPR IMPULSE.  MODERATE
ESELY LOW LVL FLOW /INVOF WEAK FRONT EXTENDING SE ALONG THE MID MO
VLY/ BENEATH 25-30 KT WSWLY 500 MB WINDS SUGGESTS POTENTIAL FOR A
FEW SUSTAINED SUPERCELLS WITH LOW LVL ROTATION.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 28015.


...CORFIDI

Tornado Watches in South Dakota, 2007Tornado Watches in Wyoming, 2007Tornado Watches in Montana, 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.