Alert archive / Wyoming / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 20, NWS Riverton, WY

July 1, 1998Big Horn County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Jul 1, 1998, 3:28 PM MDT for Big Horn County, Wyoming. It was in force for 32 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: Jul 1, 1998, 3:28 PM MDT (21:28 UTC)
Expired: Jul 1, 1998, 4:00 PM MDT
In force: 32 min
Issued by: NWS Riverton, WY
Area: Whole counties

County Big Horn County, WY

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 9.5 hours before the alert went out and 383 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: 333 J/kg
Mixed-layer CIN: -109 J/kg
Mixed-layer LCL: 1215 m above ground
0-6 km bulk shear: 2 kt
0-1 km storm-relative helicity: -25 m²/s²
0-3 km storm-relative helicity: -10 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 Jul 1, 1:00 PM MDT, 2 hours 28 minutes earlier.

Area forecast discussion, Jul 1, 1:00 PM MDT, 2 hours 28 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
100 PM MDT WED JUL 1 1998

MOIST/UNSTBL AMS ACRS MUCH OF CWFA ERLY THIS AFTN...WITH LTST ADAP
SHWG LI'S < -4 FM NW TO SE WY...AND SFC DEW POINTS RANGING FROM THE
MID 40S TO MID 50S. RADAR/SATL IMAGERY/LTG DETECTION SHWS TSTMS
ALREADY UNDERWAY OVR NW WY...AND THESE SHUD CONT...INTENSIFY...AND
SPREAD E/SE ACRS NRN/CNTRL PTNS RIW CWFA THIS AFTN/EVE. WILL MNTN SCT
TSTMS NRN/CNTRL ZNS THRU EVE HRS WITH PSBL HAIL/STG WNDS. WATR VPR
IMAGERY SHWS VRY DRY AIR INTO SW WY THIS AFTN...SO NIL POPS THERE
TNGT. MOS MINS APPR RSNBL.    DN

In the hours before

Special weather statement, Jul 1, 9:58 AM MDT, 5 hours 30 minutes before

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Special weather statement, Jul 1, 9:58 AM MDT, 5 hours 30 minutes before

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Special weather statement, Jul 1, 1:21 PM MDT, 2 hours 7 minutes before

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Special weather statement, Jul 1, 1:21 PM MDT, 2 hours 7 minutes before

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    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
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The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 30, 6:04 PM MDT	Severe Thunderstorm Warning	RIW	Hot Springs	31 min
Jul 1, 2:34 PM MDT	Severe Thunderstorm Warning	RIW	Park	31 min
Jul 1, 3:00 PM MDT	Severe Thunderstorm Warning	RIW	Park	30 min
Jul 1, 3:54 PM MDT	Severe Thunderstorm Warning	RIW	Washakie	41 min
Jul 1, 4:03 PM MDT	Severe Thunderstorm Warning	RIW	Big Horn	47 min
Jul 1, 4:17 PM MDT	Tornado Warning	RIW	Big Horn	33 min
Jul 1, 4:43 PM MDT	Severe Thunderstorm Warning	RIW	Washakie	27 min
Jul 1, 5:16 PM MDT	Severe Thunderstorm Warning	RIW	Washakie	44 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 1998 Every severe thunderstorm warning in 1998

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.