Severe Thunderstorm Watch 460

Issued

Jul 4, 2012, 12:34 PM CDT (17:34 UTC)

Expired

Jul 4, 2012, 7:40 PM CDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

Counties Aitkin County, MN, Carlton County, MN, Cass County, MN, Cook County, MN, Crow Wing County, MN, Itasca County, MN, Koochiching County, MN, Lake County, MN, Pine County, MN, Saint Louis County, MN, Ashland County, WI, Bayfield County, WI, Burnett County, WI, Douglas County, WI, Sawyer County, WI, Washburn County, WI

The Duluth radar (KDLH), 111 km from the middle of the area, began a volume at 17:38 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

20%

One or more EF2 to EF5 tornadoes

5%

Ten or more severe wind reports

50%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

50%

One or more hailstones of 2 inches or more

40%

Six or more combined severe hail and wind reports

90%

• Mesoscale Discussion 1387Jul 4, 12:25 PM CDT
• Mesoscale Discussion 1392Jul 4, 3:57 PM CDT

336 
WWUS20 KWNS 041735
SEL0  
SPC WW 041735
MNZ000-WIZ000-LSZ000-050100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 460
NWS STORM PREDICTION CENTER NORMAN OK
1235 PM CDT WED JUL 4 2012

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

       NORTHEAST MINNESOTA
       EXTREME NORTHWEST WISCONSIN
       LAKE SUPERIOR

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 1235 PM UNTIL
800 PM CDT.

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

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 65
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 80 MILES WEST
NORTHWEST OF HIBBING MINNESOTA TO 30 MILES EAST SOUTHEAST OF
SILVER BAY MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE
THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 459...

DISCUSSION...THUNDERSTORM CLUSTER ACROSS N CENTRAL MN WILL LIKELY
PERSIST AND MOVE/DEVELOP SEWD ALONG THE SURFACE WARM FRONT THROUGH
THE AFTERNOON.  STRONG INSTABILITY IS PRESENT ALONG AND S OF THE
BOUNDARY...WHERE SURFACE HEATING IS ERODING CONVECTIVE INHIBITION. 
THUS...ADDITIONAL STORM DEVELOPMENT WILL ALSO BE POSSIBLE SWD ALONG
THE GUST FRONT TRAILING FROM THE ONGOING STORMS.  GIVEN THE STRONG
INSTABILITY AND MODERATE VERTICAL SHEAR ALONG/N OF THE FRONT...A MIX
OF MULTICELL/SUPERCELL STRUCTURES CAN BE EXPECTED EARLY IN THE STORM
FORMATION...WITH SOME POTENTIAL FOR UPSCALE GROWTH INTO A LARGER
BOWING SEGMENT LATER THIS AFTERNOON.  DAMAGING WINDS AND LARGE HAIL
WILL BE THE MAIN SEVERE THREATS.

AVIATION...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 600. MEAN STORM
MOTION VECTOR 29030.


...THOMPSON

Severe Thunderstorm Watches in Minnesota, 2012Severe Thunderstorm Watches in Wisconsin, 2012Every severe thunderstorm watch in 2012

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.