Alert archive / Wyoming / Severe Thunderstorm Warnings in 1999
Severe Thunderstorm Warning 9, NWS Cheyenne, WY
NWS Cheyenne, WY issued this severe thunderstorm warning at May 21, 1999, 3:48 PM MDT for Goshen 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
- May 21, 1999, 3:48 PM MDT (21:48 UTC)
- Expired
- May 21, 1999, 4:35 PM MDT
- In force
- 47 min
- Issued by
- NWS Cheyenne, WY
- Area
- Whole counties
County Goshen County, WY
The radar
The Cheyenne radar (KCYS), 111 km from the middle of the area, began a volume at 21:52 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 |
|---|---|---|---|
| May 21, 4:15 PM MDT | Hail 0.75 | Lingle, WY | 3/4 inch hail reported 12 miles north of Lingle, 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 watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| May 21, 2:00 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
The nearest sounding before it
Rapid City, SD (KUNR), launched 12:00Z, 9.8 hours before the alert went out and 251 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1886 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- -39 m²/s²
- 0-3 km storm-relative helicity
- 21 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
999 WUUS1 KCYS 212149 RRA SVRCYS WYC015-212235- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE CHEYENNE WY 348 PM MDT FRI MAY 21 1999 THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... CENTRAL GOSHEN COUNTY IN SOUTHEASTERN WYOMING * UNTIL 435 PM MDT * AT 344 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 14 MILES NORTHWEST OF TORRINGTON OR 6 MILES NORTHWEST OF LINGLE... MOVING SOUTHEAST AT 15 MPH. * THE SEVERE THUNDERSTORM WILL BE NEAR... EXPECTED TO MOVE THROUGH THE TOWN OF LINGLE AT 405 PM MDT DAMAGING WINDS AND LARGE HAIL ARE LIKELY. GO INSIDE A STURDY BUILDING AND STAY AWAY FROM WINDOWS WCJIN-WYSE DAUGHERTY
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.
In the hours before
Special weather statement, May 21, 10:04 AM MDT, 5 hours 44 minutes before
NEZ001>003-019>021-054-055-WYZ059>070-212200- SEVERE WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 1004 AM MDT FRI MAY 21 1999 THE SEVERE WEATHER POTENTIAL IN THE NWS CHEYENNE WARNING AREA IS LOW TODAY. A COLD FRONT WILL SLOWLY TRACK SOUTHEAST ACROSS WYOMING TODAY AND TONIGHT. A MOIST AND SLIGHTLY UNSTABLE AIRMASS AHEAD OF THE FRONT IS CONDUCIVE TO THE DEVELOPMENT OF ISOLATED TO SCATTERED THUNDERSTORMS THIS AFTERNOON. HOWEVER...THE LACK OF STRONG DYNAMICS AND CONVERGENCE SHOULD PRELUDE THE DEVELOPMENT OF SEVERE THUNDERSTORMS. STRONGER THUNDERSTORMS MAINLY IN A BAND FROM DOUGLAS TO CHADRON LATE THIS AFTERNOON CAN PRODUCE SMALL HAIL...GUSTY WINDS TO 45 MPH...AND DANGEROUS LIGHTNING. SPOTTER ACTIVATION WILL NOT BE NECESSARY THIS AFTERNOON AND EVENING IN FAR SOUTHEAST WYOMING AND THE WESTERN NEBRASKA PANHANDLE. WCJIN-WYSE-WYNE COPLEY
Special weather statement, May 21, 10:04 AM MDT, 5 hours 44 minutes before
NEZ001>003-019>021-054-055-WYZ059>070-212200- SEVERE WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 1004 AM MDT FRI MAY 21 1999 THE SEVERE WEATHER POTENTIAL IN THE NWS CHEYENNE WARNING AREA IS LOW TODAY. A COLD FRONT WILL SLOWLY TRACK SOUTHEAST ACROSS WYOMING TODAY AND TONIGHT. A MOIST AND SLIGHTLY UNSTABLE AIRMASS AHEAD OF THE FRONT IS CONDUCIVE TO THE DEVELOPMENT OF ISOLATED TO SCATTERED THUNDERSTORMS THIS AFTERNOON. HOWEVER...THE LACK OF STRONG DYNAMICS AND CONVERGENCE SHOULD PRELUDE THE DEVELOPMENT OF SEVERE THUNDERSTORMS. STRONGER THUNDERSTORMS MAINLY IN A BAND FROM DOUGLAS TO CHADRON LATE THIS AFTERNOON CAN PRODUCE SMALL HAIL...GUSTY WINDS TO 45 MPH...AND DANGEROUS LIGHTNING. SPOTTER ACTIVATION WILL NOT BE NECESSARY THIS AFTERNOON AND EVENING IN FAR SOUTHEAST WYOMING AND THE WESTERN NEBRASKA PANHANDLE. WCJIN-WYSE-WYNE COPLEY
Nearby
Severe Thunderstorm Warnings in Wyoming, 1999Every 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.