Severe Thunderstorm Watch 604

Issued

Sep 1, 2012, 12:59 PM MDT (18:59 UTC)

Expired

Sep 1, 2012, 9:00 PM MDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

1.5 in

Strongest gust expected

65 kt

The Salt Lake City radar (KMTX), 84 km from the middle of the area, began a volume at 19:00 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

20%

One or more hailstones of 2 inches or more

20%

Six or more combined severe hail and wind reports

80%

• Mesoscale Discussion 1850Sep 1, 12:31 PM MDT
• Mesoscale Discussion 1853Sep 1, 3:02 PM MDT
• Mesoscale Discussion 1855Sep 1, 5:49 PM MDT
• Mesoscale Discussion 1858Sep 1, 8:02 PM MDT

697 
WWUS20 KWNS 011906
SEL4
SPC WW 011906
UTZ000-WYZ000-020300-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 604
NWS STORM PREDICTION CENTER NORMAN OK
100 PM MDT SAT SEP 1 2012

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

       CENTRAL AND NORTHERN UTAH
       SOUTHWEST WYOMING

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 100 PM UNTIL
900 PM MDT.

HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 75
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 75
STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES NORTH
NORTHWEST OF EVANSTON WYOMING TO 25 MILES EAST OF MILFORD UTAH.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU4).

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 602...WW 603...

DISCUSSION...TSTMS EXPECTED TO INCREASE OVER FAR ERN NV AND
CNTRL/NRN UT WITH CONTINUED SFC HEATING AHEAD OF ERN NV UPR IMPULSE.
SYSTEM IS EMBEDDED IN SEASONABLY STRONG...UNIDIRECTIONAL SWLY
MID/UPR-LVL FLOW /WITH 700-500 MB SPEEDS OF 35-40 KTS/. AMPLE
MOISTURE/SHEAR APPEAR PRESENT FOR SUSTAINED STORMS...INCLUDING
SUPERCELLS/BOWING SEGMENTS WITH DMGG WIND AND HAIL. STORMS MAY
EVOLVE INTO A LOOSELY-ORGANIZED CLUSTER GIVEN PRESENCE OF SW-NE
OUTFLOW BOUNDARIES OVER CNTRL/NRN UT LEFT BY EARLIER STORMS. A
TORNADO CANNOT BE RULED OUT...ESPECIALLY NEAR THESE BOUNDARIES.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 23035.


...CORFIDI

Severe Thunderstorm Watches in Utah, 2012Severe Thunderstorm Watches in Wyoming, 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.