Alert archive / Wyoming / Severe Thunderstorm Warnings in 1987
Severe Thunderstorm Warning 2, NWS Cheyenne, WY
NWS Cheyenne, WY issued this severe thunderstorm warning at May 17, 1987, 12:54 PM MDT for Laramie County, Wyoming. It was in force for 66 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 17, 1987, 12:54 PM MDT (18:54 UTC)
- Expired
- May 17, 1987, 2:00 PM MDT
- In force
- 66 min
- Issued by
- NWS Cheyenne, WY
- Area
- Whole counties
County Laramie County, WY
The radar
The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 17, 1:39 PM MDT | Hail 0.75 | Laramie, 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. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.
The nearest sounding before it
Denver, CO (KDEN), launched 12:00Z, 6.9 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.
- Mixed-layer CAPE
- 160 J/kg
- Mixed-layer CIN
- -127 J/kg
- Mixed-layer LCL
- 1490 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- -34 m²/s²
- 0-3 km storm-relative helicity
- -2 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KCYS 171854 SVRCYS WYC021-172000- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE CHEYENNE WY 1254 PM MDT SUN MAY 17 1987 THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 200 PM MDT FOR PEOPLE IN THE FOLLOWING COUNTY OF SOUTHEAST WYOMING...LARAMIE COUNTY RADAR INDICATED A SEVERE THUNDERSTORM 5 MILES WEST OF CHEYENNE. THE SEVERE THUNDERSTORM WAS MOVING TO THE NORTHEAST AT 10 MPH. SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS IN EXCESS OF 60 MPH... 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. WEILAND
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 17, 9:56 AM MDT, 2 hours 58 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 950 AM MDT SUN MAY 17 1987 LIGHT RAIN...SHOWERS AND THUNDERSTORMS WILL BE LIKELY OVER WYOMING THIS AFTERNOON AND TONIGHT. SOME OF THE THUNDERSTORMS...ESPECIALLY IN THE SOUTH AND CENTRAL MAY PRODUCE LOCALLY HEAVY RAIN AND SMALL HAIL THROUGH THE EVENING HOURS. WITH THE RAIN RECEIVED SATURDAY AND THE POTENTIAL FOR ADDITIONAL HEAVY RAIN THIS AFTERNOON AND EVENING IN THE SOUTH...THERE WILL BE A THREAT FOR URBAN AND SMALL STREAM FLOODING. PERSONS OUTDOORS IN SOUTHERN WYOMING THIS AFTERNOON AND EVENING SHOULD BE CAUTIOUS IN AN AREA OF HEAVY RAINFALL AND SEEK HIGHER GROUND IF NECESSARY. THE THREAT ONCE AGAIN OF HEAVY RAIN OVER THE SOUTH IS BEING CAUSED BY A COMBINATION OF CONSIDERABLE MOISTURE IN THE ATMOSPHERE AND A SURFACE COLD FRONT ALONG THE WYOMING AND COLORADO BORDER. A FEW THUNDERSTORMS HAVE ALREADY DEVELOPED OVER THE SOUTHWEST...WITH ADDITIONAL STORMS8 EXPECTED BY EARLY AFTERNOON OVER THE ENTIRE SOUTH. THE THUNDERSTORMS WILL CONTINUE THROUGH THE EVENING HOURS. WEILAND
Special weather statement, May 17, 10:48 AM MDT, 2 hours 6 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 1045 AM MDT SUN MAY 17 1987 THUNDERSTORMS HAVE DEVELOPED SINCE 1030 AM MDT OVER THE SNOWY RANGE AND THE LARAMIE MOUNTAINS...IN SOUTHEAST AND SOUTH CENTRAL WYOMING. AT 1035 AM MDT HEAVY RAIN AND PEA SIZE HAIL WERE REPORTED 25 MILES WEST OF CHEYENNE. OTHER SHOWERS AND THUNDERSTORMS WERE WIDELY SCATTERED OVER THAT PORTION OF WYOMING. THE HEAVIEST THUNDERSTORM WAS LOCATED ABOUT O25 MILES WEST OF CHEYENNE..ALONG THE EAST SLOPES OF THE LARAMIE RANGE. MORE SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...WITH THE POSSIBLITY OF BRIEF HEAVY RAIN AND SMALL HAIL. WEILAND
Special weather statement, May 17, 12:09 PM MDT, 45 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 1205 PM MDT SUN MAY 17 1987 SCATTERED THUNDERSTORMS CONTINUE TO DEVELOP OVER SOUTH CENTRAL AND SOUTHEAST WYOMING...WITH THE STORMS PRODUCING HEAVY RAIN OVER THE LARAMIE AND SNOWY MOUNTAIN RANGES. HEAVY RAIN...PEA SIZE HAIL AND FREQUENT LIGHTNING WAS REPORTED WITH THE THUNDERSTORMS OVER THE LARAMIE RANGE...BETWEEN LARAMIE AND CHEYENNE. INTENSE THUNDERSTORMS PRODUCING HEAVY RAIN WERE LOCATED ABOUT 8 MILES WEST OF CHEYENNE AND 10 MILES NORTHWEST OF CHEYENNE. THE THUNDERSTORMS WERE MOVING TO THE NORTHEAST AT 10 TO 15 MPH. THUNDERSTORMS WILL CONTINUE TO DEVELOP OVER SOUTH CENTRAL AND SOUTHEAST WYOMING THIS AFTERNOON...WITH BRIEF HEAVY RAIN...SMALL HAIL AND DANGEROUS LIGHTNING LIKELY. PEOPLE IN THAT PART OF THE STATE SHOULD BE AWARE OF THE POSSIBILITY OF THUNDERSTORMS...AND IF HEAVY RAIN IS EXPERIENCED...MOVE TO HIGHER GROUND. WEILAND
The office that day
Everything else NWS Cheyenne, WY issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 17, 1:53 PM MDT | Severe Thunderstorm Warning | CYS | Laramie | 67 min |
| May 17, 2:58 PM MDT | Severe Thunderstorm Warning | CYS | Laramie | 62 min |
| May 17, 4:00 PM MDT | Severe Thunderstorm Warning | CYS | Laramie | 45 min |
Nearby
Severe Thunderstorm Warnings in Wyoming, 1987Every severe thunderstorm warning in 1987
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.