Alert archive / Wyoming / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 33, NWS Cheyenne, WY

June 12, 1999Laramie County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Jun 12, 1999, 2:43 PM MDT for Laramie County, Wyoming. It was in force for 47 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: Jun 12, 1999, 2:43 PM MDT (20:43 UTC)
Expired: Jun 12, 1999, 3:30 PM MDT
In force: 47 min
Issued by: NWS Cheyenne, WY
Area: Whole counties

County Laramie County, WY

The radar

The Cheyenne radar (KCYS), 20 km from the middle of the area, began a volume at 20:46 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.

What was reported inside it

Time	Report	Where	Remark
Jun 12, 3:00 PM MDT	Hail 1.5	Carpenter, WY	1 1/2 inch hail fell 10 miles west of Carpenter, WY

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 8.7 hours before the alert went out and 202 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: 112 J/kg
Mixed-layer CIN: -183 J/kg
Mixed-layer LCL: 1274 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: -29 m²/s²
0-3 km storm-relative helicity: -22 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 Cheyenne, WY wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 12, 2:25 PM MDT, 18 minutes earlier.

Area forecast discussion, Jun 12, 2:25 PM MDT, 18 minutes before

SOUTHEAST WYOMING/NEBRASKA PANHANDLE AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
225 PM MDT SAT JUN 12 1999

WEAK UPR FTR MOVG ACRS SE WY/N CNTRL CO...TRIGGERING SCT STG TSTMS.
INSTBLTYS SUPPORT CONTD DVLPMNT ACRS REST OF CWA THIS EVNG.  MDLS
SORT OF WASH OUT FTR HWVR AS THEY FOCUS MORE ON S/WV DRPG ESE OUT OF
SRN MT.  ETA WAS QUICKEST WITH THIS FTR AND ASSOCD NEW SURGE OF
COOLER AIR...IT MAY BE A BIT TOO FAST THO...SO HAVE OPTED TO GO WITH
NGM/ETA MIX IN SHRT RNG.  BOTH MDLS HAVE DVLPMNT ACRS NERN/E CNTRL
WY LTR THIS EVNG...AND DRAG IT ESE INTO CWA.  WILL LEAVE SOME PCPN
IN MANY AREAS ALL NGT.  SHLD BE SOME MRNG SHWRS ARND SUN...WITH LESS
ACTVTY ARND IN THE AFTN/EVNG HOURS ACCORDG TO MDLS AS MORE STBL AIR
MOVES INTO REGION BEHIND SFC/UPR FTRS.  IN LNGR TERM...AVN STILL
WANTS TO DROP A S/WV TROF ACRS STATE FROM NW TO SE ON MON AFTN INTO
TUE MRNG...SO WILL GO WITH COOLER MOST AREAS ON TUE.

.CYS...
WY...NONE.
NE...NONE.

JAD

In the hours before

Special weather statement, Jun 12, 10:15 AM MDT, 4 hours 28 minutes before

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Special weather statement, Jun 12, 10:15 AM MDT, 4 hours 28 minutes before

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 12, 4:48 PM MDT	Severe Thunderstorm Warning	CYS	Sioux	47 min
Jun 12, 5:07 PM MDT	Severe Thunderstorm Warning	CYS	Morrill, Scotts Bluff	33 min
Jun 12, 5:39 PM MDT	Severe Thunderstorm Warning	CYS	Morrill	31 min
Jun 12, 1:52 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	48 min
Jun 12, 3:32 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	48 min
Jun 12, 4:33 PM MDT	Tornado Warning	CYS	Converse	32 min
Jun 12, 5:05 PM MDT	Tornado Warning	CYS	Converse	30 min
Jun 12, 5:37 PM MDT	Tornado Warning	CYS	Converse	28 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 1999 Every severe thunderstorm warning in 1999

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.