Severe Thunderstorm Watch 451

Issued

Jul 1, 2012, 5:04 PM MDT (23:04 UTC)

Expired

Jul 1, 2012, 11:00 PM MDT

In force

6 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Great Falls radar (KTFX), 99 km from the middle of the area, began a volume at 23:04 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

10%

One or more EF2 to EF5 tornadoes

5%

Ten or more severe wind reports

30%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

20%

One or more hailstones of 2 inches or more

20%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 1346Jul 1, 4:34 PM MDT
• Mesoscale Discussion 1356Jul 1, 7:10 PM MDT

517 
WWUS20 KWNS 012305
SEL1
SPC WW 012305
MTZ000-020500-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 451
NWS STORM PREDICTION CENTER NORMAN OK
455 PM MDT SUN JUL 1 2012

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

       WESTERN AND CENTRAL MONTANA

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 455 PM UNTIL
1100 PM MDT.

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 100
STATUTE MILES EAST AND WEST OF A LINE FROM 55 MILES SOUTH OF
BOZEMAN MONTANA TO 40 MILES NORTHWEST OF HAVRE MONTANA.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU1).

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 442...WW 443...WW
444...WW 445...WW 446...WW 447...WW 448...WW 449...WW 450...

DISCUSSION...SVR THREAT INCREASING OVER WW AREA THROUGH REMAINDER
AFTERNOON...AS ACTIVITY MOVES NEWD OUT OF PERSISTENT E-CENTRAL
ID/SWRN MT CONVECTIVE GENESIS REGION...AND ADDITIONAL TSTMS DEVELOP
ALONG AND E OF EWD-MOVING BOUNDARY OVER W-CENTRAL MT.  WITH AT LEAST
MRGLLY FAVORABLE MOISTURE/BUOYANCY AND PLENTY OF DEEP-LAYER SHEAR
FOR SUPERCELLS...SMALL BOWS AND SVR MULTICELLS ALL ARE POSSIBLE WITH
LARGE HAIL AND DAMAGING GUSTS.

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 500. MEAN STORM
MOTION VECTOR 23035.


...EDWARDS

Severe Thunderstorm Watches in Montana, 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.