Severe Thunderstorm Watch 340

Issued

Jun 2, 2012, 2:10 PM MDT (20:10 UTC)

Expired

Jun 2, 2012, 9:00 PM MDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

1.5 in

Strongest gust expected

60 kt

The Billings radar (KBLX), 100 km from the middle of the area, began a volume at 20:12 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

30%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

30%

One or more hailstones of 2 inches or more

20%

Six or more combined severe hail and wind reports

60%

• Mesoscale Discussion 1020Jun 2, 12:52 PM MDT
• Mesoscale Discussion 1023Jun 2, 6:08 PM MDT

641 
WWUS20 KWNS 022012
SEL0
SPC WW 022012
MTZ000-030300-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 340
NWS STORM PREDICTION CENTER NORMAN OK
210 PM MDT SAT JUN 2 2012

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

       SOUTH-CENTRAL AND EASTERN MONTANA

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 210 PM UNTIL
900 PM MDT.

HAIL TO 1.5 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 95
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 40 MILES NORTH
NORTHWEST OF BOZEMAN MONTANA TO 25 MILES NORTH OF BAKER MONTANA.
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.

DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN BOTH COVERAGE AND
INTENSITY ACROSS PARTS OF CNTRL...SRN AND ERN MT THROUGH THE LATE
AFTERNOON AND INTO THE EVENING. MID/UPPER LEVEL HEIGHT FALLS WILL
ACT TO SUPPRESS RIDGE AXIS ACROSS THE REGION WITH SUBSEQUENT LARGE
SCALE ASCENT ACTING ON A MOIST AND WEAKLY UNSTABLE AIRMASS
SUFFICIENT TO RESULT IN SCATTERED VIGOROUS CONVECTION. DEEP-LAYER
SHEAR SHOULD ALLOW FOR UPDRAFT PERSISTENCE AND SOME ORGANIZATION
WITH CELLS AND/OR SHORT LINE SEGMENTS POSING A THREAT FOR SEVERE
HAIL AND HIGH WINDS. STORMS MAY CONGEAL ACROSS PORTIONS OF ERN MT
DURING THE EVENING WITH WIND POTENTIAL POSSIBLY INCREASING OVER
THESE AREAS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 400. MEAN STORM
MOTION VECTOR 25025.


...CARBIN

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.