Tornado Watch 780

Issued

Sep 12, 2005, 7:45 PM CDT (00:45 UTC)

Expired

Sep 13, 2005, 2:00 AM CDT

In force

6 hr

Issued by

the Storm Prediction Center

The Sioux Falls radar (KFSD), 125 km from the middle of the area, began a volume at 00:45 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 2180Sep 12, 6:47 PM CDT
• Mesoscale Discussion 2182Sep 12, 9:36 PM CDT
• Mesoscale Discussion 2184Sep 13, 1:19 AM CDT

000 
WWUS20 KWNS 130048
SEL0  
SPC WW 130048
IAZ000-MNZ000-SDZ000-130700-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 780
NWS STORM PREDICTION CENTER NORMAN OK
745 PM CDT MON SEP 12 2005

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

       NORTHWEST IOWA
       SOUTHERN MINNESOTA
       SOUTHEAST SOUTH DAKOTA

EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 745 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 APPROXIMATELY ALONG AND 65 STATUTE MILES
NORTH AND SOUTH OF A LINE FROM 45 MILES WEST SOUTHWEST OF
BROOKINGS SOUTH DAKOTA TO 30 MILES SOUTHEAST OF MINNEAPOLIS
MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).

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...THIS TORNADO WATCH REPLACES TORNADO
WATCH NUMBER 778. WATCH NUMBER 778 WILL NOT BE IN EFFECT AFTER 745
PM CDT. CONTINUE...WW 779...

DISCUSSION...WIDESPREAD CONVECTION CONTINUES TO SPREAD ENEWD FROM SE
SD/SW MN INTO CENTRAL MN ALONG A SURFACE BAROCLINIC ZONE...WHILE A
SECONDARY BOUNDARY EXISTS NEAR THE IA/MN BORDER.  DESPITE THE
WIDESPREAD CONVECTION AND SOME DESTRUCTIVE STORM INTERFERENCE...RICH
MOISTURE AND SUFFICIENTLY STRONG VERTICAL SHEAR WILL MAINTAIN A
SUPERCELL/TORNADO THREAT FOR THE NEXT FEW HOURS IN MN. 
OTHERWISE...THE MODERATE INSTABILITY WILL SUPPORT A CONTINUED THREAT
FOR LARGE HAIL AND DAMAGING WINDS WITH THE MORE INTENSE STORMS INTO
THE OVERNIGHT HOURS.

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 26030.


...THOMPSON

445,0974 452,0924 433,0924 430,0974

Tornado Watches in Minnesota, 2005Tornado Watches in South Dakota, 2005Tornado Watches in Iowa, 2005Every tornado watch in 2005

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.