Severe Thunderstorm Watch 359

Issued

Jun 5, 2012, 1:37 PM MDT (19:37 UTC)

Expired

Jun 5, 2012, 8:57 PM MDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

Counties Broadwater County, MT, Carbon County, MT, Gallatin County, MT, Golden Valley County, MT, Jefferson County, MT, Madison County, MT, Meagher County, MT, Park County, MT, Stillwater County, MT, Sweet Grass County, MT, Wheatland County, MT

The Billings radar (KBLX), 194 km from the middle of the area, began a volume at 19:42 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

70%

• Mesoscale Discussion 1071Jun 5, 12:54 PM MDT
• Mesoscale Discussion 1076Jun 5, 4:21 PM MDT
• Mesoscale Discussion 1077Jun 5, 4:48 PM MDT
• Mesoscale Discussion 1080Jun 5, 7:39 PM MDT

464 
WWUS20 KWNS 051941
SEL9
SPC WW 051941
MTZ000-060300-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 359
NWS STORM PREDICTION CENTER NORMAN OK
140 PM MDT TUE JUN 5 2012

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

       SOUTHWEST AND CENTRAL MONTANA

EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 140 PM UNTIL
900 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 85
STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES SOUTH OF
LIVINGSTON MONTANA TO 55 MILES NORTH OF BOZEMAN MONTANA.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU9).

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 358...

DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND
INTENSITY THIS AFTERNOON ALONG THE HIGH TERRAIN AS LARGE-SCALE
FORCING FOR ASCENT STRENGTHENS FROM THE SW.  AMBIENT AIR MASS IS
CHARACTERIZED BY STEEP LAPSE RATES AND DEWPOINTS IN THE MID 40S-LOW
50S WITH RESULTING SBCAPE OF 500-1000 J/KG.  VERTICAL SHEAR IS ALSO
FORECAST TO STRENGTHEN MARKEDLY LATE THIS AFTERNOON INTO EVENING IN
CONJUNCTION WITH ARRIVAL OF NEGATIVELY TILTED MIDLEVEL TROUGH.  AS
SUCH...THE THREAT FOR ORGANIZED STORM MODES...INCLUDING SUPERCELLS
WILL INCREASE WITH A RISK FOR DAMAGING WINDS AND LARGE HAIL.

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 450. MEAN STORM
MOTION VECTOR 17035.


...MEAD

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.