Alert archive / Wyoming / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 5, NWS Riverton, WY

June 1, 2002Johnson County, Natrona County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Jun 1, 2002, 6:42 PM MDT for Johnson County, Natrona County, Wyoming. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jun 1, 2002, 6:42 PM MDT (00:42 UTC)
Expired: Jun 1, 2002, 7:30 PM MDT
In force: 48 min
Issued by: NWS Riverton, WY
Area: Whole counties

Counties Johnson County, WY, Natrona County, WY

The radar

The Riverton/Lander radar (KRIW), 152 km from the middle of the area, began a volume at 00:45 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jun 1, 4:30 PM MDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Riverton, WY (KRIW), launched 00:00Z, 0.7 hours before the alert went out and 146 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2798 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: -41 m²/s²
0-3 km storm-relative helicity: 151 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.

463 
WUUS55 KRIW 020042
SVRRIW
WYC019-025-020130-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE RIVERTON WY
640 PM MDT SAT JUN 1 2002

THE NATIONAL WEATHER SERVICE IN RIVERTON HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHEASTERN NATRONA COUNTY IN CENTRAL WYOMING
  SOUTHEAST JOHNSON COUNTY IN NORTH CENTRAL WYOMING

* UNTIL 730 PM MDT

* AT 640 PM MDT...A TRAINED WEATHER SPOTTER REPORTED A SEVERE   
THUNDERSTORM PRODUCING UP TO QUARTER SIZE HAIL IN EDGERTON...OR 
ABOUT 35 MILES NORTH OF CASPER.  DOPPLER RADAR INDICATED THE STORM 
MOVING EAST AT 30 MPH.

THE SEVERE THUNDERSTORM IS CAPABLE OF PRODUCING...
 DAMAGING HAIL UP TO THE SIZE OF GOLFBALLS.
 DAMAGING WINDS GREATER THAN 60 MILES AN HOUR.
 VERY HEAVY RAINFALL WHICH MAY CAUSE LOCALIZED FLOODING.
 FREQUENT CLOUD-TO-GROUND LIGHTNING.

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH YOU SHOULD PREPARE
FOR DAMAGING WINDS IN EXCESS OF 55 MPH...LARGE HAIL...AND DEADLY
LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY
INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY
WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST
OFFICE IN RIVERTON.

$$
LAT...LON 4385 10672 4314 10657 4314 10614 4380 10611

SKRBAC

WCJIN-WYNE

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Riverton, WY wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 1, 3:08 PM MDT, 3 hours 34 minutes earlier.

Area forecast discussion, Jun 1, 3:08 PM MDT, 3 hours 34 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
308 PM MDT SAT JUN 1 2002

RIDGING STILL VERY APPARENT OVER THE REGION AS SHOWERS AND STORMS
CONTINUE TO ROTATE AROUND PERIPHERY JUST NORTH OF WYOMING.  DECENT
LITTLE COMPLEX JUST SKIRTING THE NORTHWEST CORNER OF YELLOWSTONE...
BUT MOST OF ITS EFFECTS SHOULD MISS YELLOWSTONE.  AN AREA OF MAINLY
MID AND HIGH CLOUDS ROTATING INTO SOUTHWEST WYOMING HAVING A TUFF
TIME HOLDING TOGETHER AS THEY ENTER THE HIGHER PRESSURE.  TROF
SWOOPING RATHER QUICKLY INTO THE WEST COAST AS THINGS GET SORT OF
BUNCHED UP IN THE INTERMOUNTAIN REGION FOR A SPELL.  NOT MUCH IN THE
WAY OF MECHANICAL FORCING TODAY IN THE ANTICIPATED ABSENCE OF ANY
SHORTWAVE ACTIVITY.  HOWEVER...A DAY FOR THERMODYNAMICS AS
ATMOSPHERE EXPECTED TO BECOME MODERATELY UNSTABLE ACROSS THE NORTH
AND NORTHEAST.  COINCIDENT WITH THE INSTABILITY IS GOOD LOW LEVEL
CONVERGENCE/UPPER LEVEL DIVERGENCE AND THETA-E RIDGING.  MODEL
SOUNDINGS IN THIS AREA INDICATES GOOD POTENTIAL FOR STRONG WIND AND
LARGE HAIL...THO WET BULB IS A LITTLE ON THE HIGH SIDE.  SURFACE LOW
CROSSING WYOMING TODAY SHOULD BE MOVING INTO THE PLAINS
TONIGHT...BRINGING GOOD VEERING OF LOWER LEVEL WIND ACROSS THE
NORTHEAST AND EAST PARTS OF THE CWA.  SUNDAY THE TROF MOVES CLOSER
WITH WYOMING IN GOOD SOUTHWEST FLOW EARLY...THEN A COLD FRONT MOVES
INTO THE NORTH BY LATE AFTERNOON...PROVIDING A GOOD FOCUSING
MECHANISM FOR ENHANCED CONVECTION AS THE ATMOSPHERE ONCE AGAIN
EXPECTED TO BE QUITE UNSTABLE WITH GOOD LOW LEVEL CONVERGENCE/UPPER
LEVEL DIVERGENCE ACROSS THE NORTH AND EAST ONCE AGAIN.  FRONT THEN
MOVES SOUTH ACROSS THE REGION SUNDAY NIGHT PROVIDING NORTHEAST FLOW
FOR MOST INTO OR THRU MONDAY.  TROFINESS HANGS AROUND FOR MUCH OF
THE EARLY PART OF NEXT WEEK...MAKING FOR UNSETTLED AND COOLER
CONDITIONS.  OVERALL FORECAST TREND UNCHANGED...ONLY MINOR CHANGES
MADE.

FIRE WEATHER...RED FLAG WARNING TODAY FOR SOUTHWEST WYOMING FIRE
ZONES AS WINDY...DRY...AND WARM CONDITIONS PERSIST WITH VERY LOW RH
VALUES AND POSSIBILITY OF DRY THUNDERSTORMS.

.RIW...RED FLAG WARNING TODAY WYOMING FIRE WEATHER ZONES 277 AND 279.

In the hours before

Local storm report, Jun 1, 5:44 PM MDT, 58 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RIVERTON, WY
544 PM MDT SAT JUN 1 2002

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0525 PM    23 S GREEN RIVER          WY   62 MPH TSTM WIND GUST
06/01/02   SWEETWATER                     OBSERVER REPORTED 62 MPH
                                          WIND SUSTAINED FOR ONE
                                          HOUR.REPORTED BY CO-OP
                                          OBSERVERS AT THE BUCKBOARD
                                          MARINA, NEAR FLAMING GORGE
                                          RESERVOIR.

Local storm report, Jun 1, 6:29 PM MDT, 13 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RIVERTON, WY
629 PM MDT SAT JUN 1 2002

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0525 PM    GRANGER                   WY   WIND DAMAGE
06/01/02   SWEETWATER                     METAL SHED BLEW INTO A
                                          POLICE OFFICERS HOUSE.
                                          REPORTED BY LAW ENFORCEMENT

Local storm report, Jun 1, 6:32 PM MDT, 10 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RIVERTON, WY
632 PM MDT SAT JUN 1 2002

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0550 PM    KEMMERER                  WY   80 MPH NON TSTM WIND GUST
06/01/02   LINCOLN                        WINDS BLOWING TRUCKS OFF
                                          U.S. HIGHWAY 30.REPORTED BY
                                          LAW ENFORCEMENT

Local storm report, Jun 1, 6:42 PM MDT, 0 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RIVERTON, WY
642 PM MDT SAT JUN 1 2002

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0610 PM    N ROCK SPRINGS            WY   WIND DAMAGE
06/01/02   SWEETWATER                     10 CARS BLOWN OFF U.S.
                                          HIGHWAY 191 NORTH OF ROCK
                                          SPRINGS. ONE CAR SEVERELY
                                          DAMAGED. ONE STOCK TRUCK
                                          BLOWN OVER.REPORTED BY LAW
                                          ENFORCEMENT

The office that day

Everything else NWS Riverton, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 1, 6:17 PM MDT	Severe Thunderstorm Warning	RIW	Big Horn	58 min
Jun 1, 6:36 PM MDT	Severe Thunderstorm Warning	RIW	Sublette, Sweetwater	54 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 2, 12:36 PM MDT	Severe Thunderstorm Warning	RIW	Big Horn, Washakie	54 min
Jun 2, 1:33 PM MDT	Severe Thunderstorm Warning	RIW	Johnson, Washakie	57 min
Jun 2, 2:28 PM MDT	Severe Thunderstorm Warning	RIW	Johnson	62 min
Jun 2, 3:33 PM MDT	Severe Thunderstorm Warning	RIW	Johnson	27 min
Jun 2, 5:53 PM MDT	Severe Thunderstorm Warning	RIW	Johnson, Natrona	22 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2002 Every severe thunderstorm warning 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.