Alert archive / Wyoming / Severe Thunderstorm Watches in 2002

Severe Thunderstorm Watch 367

June 1, 200213 counties in Wyoming

The Storm Prediction Center issued this severe thunderstorm watch at Jun 1, 2002, 4:30 PM MDT for 13 counties in Wyoming. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Jun 1, 2002, 4:30 PM MDT (22:30 UTC)
Expired: Jun 1, 2002, 9:00 PM MDT
In force: 5 hr
Issued by: the Storm Prediction Center

Counties Big Horn County, WY, Campbell County, WY, Converse County, WY, Fremont County, WY, Goshen County, WY, Hot Springs County, WY, Johnson County, WY, Natrona County, WY, Niobrara County, WY, Platte County, WY, Sheridan County, WY, Washakie County, WY, Weston County, WY

The radar

The Riverton/Lander radar (KRIW), 158 km from the middle of the area, began a volume at 22:33 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.

Warnings issued inside it

8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jun 1, 6:17 PM MDT	Severe Thunderstorm Warning	RIW	Big Horn	58 min
Jun 1, 6:42 PM MDT	Severe Thunderstorm Warning	RIW	Johnson, Natrona	48 min
Jun 1, 6:51 PM MDT	Severe Thunderstorm Warning	CYS	Goshen, Platte	39 min
Jun 1, 6:52 PM MDT	Severe Thunderstorm Warning	CYS	Goshen, Platte	38 min
Jun 1, 7:24 PM MDT	Severe Thunderstorm Warning	RIW	Fremont, Natrona	66 min
Jun 1, 7:41 PM MDT	Flash Flood Warning	RIW	Big Horn	4 hr
Jun 1, 7:49 PM MDT	Severe Thunderstorm Warning	UNR	Weston	56 min
Jun 1, 8:20 PM MDT	Severe Thunderstorm Warning	UNR	Campbell	40 min

The nearest sounding before it

Riverton, WY (KRIW), launched 12:00Z, 10.5 hours before the alert went out and 152 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 71 J/kg
Mixed-layer CIN: -503 J/kg
Mixed-layer LCL: 1994 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 144 m²/s²
0-3 km storm-relative helicity: 247 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000
WWUS20 KWNS 012211
SEL7  
SPC WW 012208
WYZ000-020300-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 367
STORM PREDICTION CENTER NORMAN OK
408 PM MDT SAT JUN 1 2002

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

   CENTRAL AND EASTERN WYOMING                            

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 430 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 ALONG AND 90 STATUTE MILES
NORTH AND SOUTH OF A LINE FROM 35 MILES WEST SOUTHWEST OF WORLAND
WYOMING TO 75 MILES EAST NORTHEAST OF DOUGLAS WYOMING.

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 366...

DISCUSSION...SCATTERED THUNDERSTORMS HAVE BEGUN TO INTENSIFY OVER
CENTRAL WY...IN REGION OF MOIST EASTERLY LOW LEVEL WINDS AND
MODERATE INSTABILITY.  ACTIVITY SHOULD CONTINUE TO INCREASE AS
UPPER TROUGH OVER UT ROTATES INTO REGION.  SUFFICIENT VERTICAL
SHEAR AND INSTABILITY IS PRESENT FOR SUPERCELLS PRODUCING LARGE
HAIL AND DAMAGING WINDS.

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.

...HART

450,1083 442,1040 415,1040 422,1083

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 1, 4:00 PM MDT	Severe Thunderstorm Watch	SPC	Lincoln, Park, Sublette, Teton	5 hr

Nearby

Severe Thunderstorm Watches in Wyoming, 2002 Every severe thunderstorm watch in 2002

Sources

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.