Alert archive / Wyoming / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 21, NWS Riverton, WY

September 1, 2012Fremont County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Sep 1, 2012, 6:59 PM MDT for Fremont County, Wyoming. It was in force for 46 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Sep 1, 2012, 6:59 PM MDT (00:59 UTC)
Expired: Sep 1, 2012, 7:45 PM MDT
In force: 46 min
Issued by: NWS Riverton, WY
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Fremont County, WY

The radar

The Riverton/Lander radar (KRIW), 17 km from the middle of the area, began a volume at 01:02 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, 1.0 hours before the alert went out and 23 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: 3465 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: -1 m²/s²
0-3 km storm-relative helicity: 24 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.

617 
WUUS55 KRIW 020059
SVRRIW
WYC013-020145-
/O.NEW.KRIW.SV.W.0021.120902T0059Z-120902T0145Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE RIVERTON WY
659 PM MDT SAT SEP 1 2012

THE NATIONAL WEATHER SERVICE IN RIVERTON HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL FREMONT COUNTY IN CENTRAL WYOMING...

* UNTIL 745 PM MDT

* AT 654 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN
  EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING
  FROM FORT WASHAKIE TO SINKS CANYON STATE PARK...AND MOVING EAST    
  AT 25 MPH.  THESE DAMAGING WIND GUSTS WILL OCCUR WELL OUT AHEAD OF 
  THE MAIN LINE OF STORMS.  

* SEVERE THUNDERSTORMS WILL BE NEAR...
  U.S. HWY 287 MILE MARKER 80...RED CANYON...MILFORD AND LANDER
  AROUND 705 PM MDT.
  U.S. HWY 287 MILE MARKER 70...HWY JCT 287 AND 28 AND HWY JCT 287
  AND 132 AROUND 710 PM MDT.
  ETHETE AROUND 720 PM MDT.
  U.S. HWY 287 MILE MARKER 60 AND HUDSON AROUND 730 PM MDT.
  KINNEAR AROUND 740 PM MDT.
  ARAPAHOE...OCEAN LAKE AND RIVERTON AROUND 745 PM MDT.

OTHER LOCATIONS IMPACTED BY THESE SEVERE THUNDERSTORMS INCLUDE STATE
HWY 132...ST. STEPHENS AND U.S. HWY 26 MILE MARKER 130.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR
YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

&&

REPORT SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN
RIVERTON AT 1-800-211-1448.

LAT...LON 4344 10867 4272 10815 4261 10877 4310 10916
TIME...MOT...LOC 0057Z 256DEG 20KT 4305 10898 4271 10871
WIND...HAIL 60MPH <.75IN

$$

MEUNIER

1 follow-up statement

672 
WWUS55 KRIW 020118
SVSRIW

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
718 PM MDT SAT SEP 1 2012

WYC013-020145-
/O.CON.KRIW.SV.W.0021.000000T0000Z-120902T0145Z/
FREMONT WY-
718 PM MDT SAT SEP 1 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR CENTRAL
FREMONT COUNTY UNTIL 745 PM MDT...

AT 715 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DESTRUCTIVE WINDS
IN EXCESS OF 70 MPH.  THESE STORMS WERE LOCATED ALONG A LINE
EXTENDING FROM 6 MILES NORTH OF PILOT BUTTE RESERVOIR TO 5 MILES EAST
OF HUDSON...MOVING NORTHEAST AT 45 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  STATE HWY 135 MILE MARKER 10 AND RIVERTON AROUND 725 PM MDT.

OTHER LOCATIONS IMPACTED BY SEVERE THUNDERSTORMS INCLUDE FREMONT
COUNTY FAIRGROUNDS...U.S. HWY 26 MILE MARKER 130 AND ST. STEPHENS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

WIND DAMAGE WITH THIS STORM WILL OCCUR WELL AHEAD OF ANY RAIN OR 
LIGHTNING. DO NOT WAIT FOR THE SOUND OF THUNDER BEFORE TAKING COVER. 
SEEK SHELTER IMMEDIATELY INSIDE A STURDY STRUCTURE AND STAY AWAY FROM
WINDOWS.

&&

REPORT SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN
RIVERTON AT 1-800-211-1448.

LAT...LON 4271 10858 4315 10905 4344 10867 4272 10815
TIME...MOT...LOC 0118Z 226DEG 40KT 4330 10875 4290 10845
WIND...HAIL 70MPH <.75IN

$$

MEUNIER

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 1, 6:13 PM MDT	Special Weather Statement	RIW		62 min
Sep 1, 6:26 PM MDT	Special Weather Statement	RIW	Fremont	49 min
Sep 1, 7:35 PM MDT	Severe Thunderstorm Warning	RIW	Fremont	39 min
Sep 1, 7:39 PM MDT	Special Weather Statement	RIW	Teton	66 min
Sep 2, 3:18 PM MDT	Fire Weather Watch	RIW	Fremont, Hot Springs, Johnson, Lincoln, Natrona, Park and 3 more	18 hr

Nearby

Severe Thunderstorm Warnings in Wyoming, 2012 Every severe thunderstorm warning in 2012

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.