Alert archive / Wyoming / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 34, NWS Riverton, WY

August 28, 2002Fremont County, Natrona County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Aug 28, 2002, 7:51 PM MDT for Fremont County, Natrona County, Wyoming. It was in force for 24 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: Aug 28, 2002, 7:51 PM MDT (01:51 UTC)
Expired: Aug 28, 2002, 8:15 PM MDT
In force: 24 min
Issued by: NWS Riverton, WY
Area: Whole counties

Counties Fremont County, WY, Natrona County, WY

The radar

The Riverton/Lander radar (KRIW), 62 km from the middle of the area, began a volume at 01:50 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 nearest sounding before it

Riverton, WY (KRIW), launched 00:00Z, 1.9 hours before the alert went out and 56 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: 970 J/kg
Mixed-layer CIN: -57 J/kg
Mixed-layer LCL: 1454 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 2 m²/s²
0-3 km storm-relative helicity: 94 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.3

Open this sounding in Storm Lab

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 Aug 28, 2:55 PM MDT, 4 hours 56 minutes earlier.

Area forecast discussion, Aug 28, 2:55 PM MDT, 4 hours 56 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
255 PM MDT WED AUG 28 2002

FIRST PERIOD FORECAST MORE COMPLICATED TODAY THAN IN RECENT DAYS
WITH DYNAMICS MORE SUBTLE.  VERTICAL MODEL CROSS SECTIONS INDICATE
ONLY WEAK UPWARD MOTION OVERNIGHT...HINTING AT MINIMAL ACTIVITY.
HOWEVER...AFTERNOON CONVECTION OVER WEST AND NORTHWEST MOUNTAINS
WERE PROGGED BY ALL MODELS...WITH MESOETA SHOWING BEST PLACEMENT.
SPEED MAX SHOWING UP ON WATER VAPOR IMAGERY EXTRAPOLATES TO CENTRAL
AND NORTHEAST WY BY MID EVENING...SUPPORTING MESOETA SOLUTION OF
THUNDERSTORMS ZEROING IN ON OWL CREEKS AND SOUTHERN BIG HORNS.  WITH
SURFACE UPSLOPE FLOW WEAK BUT PERSISITENT...COULD GET A FEW STORMS
THAT BACKBUILD ALONG SOME OF THE MOUNTAINS AND DUMP VERY HEAVY
RAIN...HOPEFULLY NOT IN SOUTHERN JOHNSON COUNTY WHERE THEY ARE STILL
CLEANING UP FROM FLASH FLOOD TUESDAY MORNING.  THIS WILL NEED TO BE
CLOSELY WATCHED BY EVENING/MID SHIFTS.

FARTHER OUT...BETTER OVERALL DYNAMICS FOR MORE WIDESPREAD CONVECTION
TOMORROW AFTERNOON AND EVENING BEFORE TROF TO WEST FILLS IN AND WE
DRY OUT FOR FRIDAY.

.RIW...NONE.

JBS

In the hours before

Local storm report, Aug 28, 7:16 PM MDT, 35 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RIVERTON, WY
716 PM MDT WED AUG 28 2002

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

0446 PM    18 NW PINEDALE            WY   1.00 INCH HAIL
08/28/02   SUBLETTE                       REPORTED BY SPOTTERS

0505 PM    15 N CORA                 WY   .75 INCH HAIL
08/28/02   SUBLETTE                       REPORTED BY SPOTTERS

DAL

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 29, 12:48 PM MDT	Severe Thunderstorm Warning	RIW	Lincoln, Sublette	42 min
Aug 29, 1:19 PM MDT	Severe Thunderstorm Warning	RIW	Lincoln, Sublette	11 min
Aug 29, 2:51 PM MDT	Flash Flood Warning	RIW	Johnson	3 hr
Aug 29, 2:52 PM MDT	Severe Thunderstorm Warning	RIW	Park	38 min
Aug 29, 2:54 PM MDT	Severe Thunderstorm Warning	RIW	Park	51 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.