Tornado Watch 401

Issued

Jun 16, 2007, 4:10 PM MDT (22:10 UTC)

Expired

Jun 17, 2007, 1:00 AM MDT

In force

9 hr

Issued by

the Storm Prediction Center

Largest hail expected

2.5 in

Strongest gust expected

60 kt

The Billings radar (KBLX), 181 km from the middle of the area, began a volume at 22:10 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

50%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

40%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

60%

One or more hailstones of 2 inches or more

50%

Six or more combined severe hail and wind reports

90%

• Mesoscale Discussion 1166Jun 16, 2:53 PM MDT
• Mesoscale Discussion 1168Jun 16, 6:59 PM MDT
• Mesoscale Discussion 1169Jun 16, 8:06 PM MDT
• Mesoscale Discussion 1171Jun 16, 10:23 PM MDT
• Mesoscale Discussion 1172Jun 17, 12:32 AM MDT

000
WWUS20 KWNS 162214
SEL1  
SPC WW 162214
MTZ000-WYZ000-170700-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 401
NWS STORM PREDICTION CENTER NORMAN OK
410 PM MDT SAT JUN 16 2007

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

       EASTERN MONTANA
       NORTHEAST WYOMING

EFFECTIVE THIS SATURDAY AFTERNOON AND SUNDAY MORNING FROM 410 PM
UNTIL 100 AM MDT.

TORNADOES...HAIL TO 2.5 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 85 STATUTE
MILES EAST AND WEST OF A LINE FROM 25 MILES NORTH OF GLASGOW
MONTANA TO 65 MILES SOUTH SOUTHWEST OF MOORCROFT WYOMING.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU1).

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...CONTINUE...WW 400...

DISCUSSION...A STRONG MID LEVEL TROUGH AND ASSOCIATED SURFACE LOW
WILL MOVE EWD TO ERN MT BY TONIGHT...WITH CONVECTION LIKELY TO
INCREASE IN COVERAGE/INTENSITY WHILE SPREADING EWD FROM CENTRAL INTO
ERN MT LATE THIS EVENING INTO TONIGHT.  THE PRIMARY CONVECTIVE
CLUSTER WILL BE PRECEDED BY THE ISOLATED SUPERCELL MOVING ALONG THE
WARM FRONT IN NE MT...AND THE POTENTIAL FOR SUPERCELL DEVELOPMENT
NEAR AND IMMEDIATELY E OF THE BIGHORNS IN WY.  A GRADUAL INCREASE IN
LOW-LEVEL MOISTURE BENEATH STEEP MID LEVEL LAPSE RATES...AND STRONG
DEEP LAYER SHEAR...WILL SUPPORT SUPERCELLS CAPABLE OF PRODUCING
LARGE HAIL AND A FEW TORNADOES.  THE THREAT FOR DAMAGING WINDS MAY
INCREASE TONIGHT IN CONJUNCTION WITH STORM MERGERS AND THE
POSSIBILITY OF BOW ECHO FORMATION.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 27025.


...THOMPSON

Tornado Watches in Montana, 2007Tornado Watches in Wyoming, 2007Every tornado watch in 2007

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.