Alert archive / Wyoming / Severe Thunderstorm Warnings in 1991
Severe Thunderstorm Warning 9, NWS Cheyenne, WY
NWS Cheyenne, WY issued this severe thunderstorm warning at May 10, 1991, 6:29 PM MDT for Goshen County, Platte County, Wyoming. It was in force for 31 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 10, 1991, 6:29 PM MDT (00:29 UTC)
- Expired
- May 10, 1991, 7:00 PM MDT
- In force
- 31 min
- Issued by
- NWS Cheyenne, WY
- Area
- Whole counties
Counties Goshen County, WY, Platte County, WY
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 10, 7:04 PM MDT | Hail 1.75 | Platte, 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
Rapid City, SD (KRAP), launched 00:00Z, 0.5 hours before the alert went out and 261 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
- 2978 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 294 m²/s²
- 0-3 km storm-relative helicity
- 325 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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.
In the hours before
Special weather statement, May 10, 2:50 PM MDT, 3 hours 39 minutes before
WYZ012-017-110050- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 250 PM MDT FRI MAY 10 1991 ...A TORNADO WATCH HAS BEEN ISSUED FOR EXTREME EASTERN WYOMING UNTIL 9 PM THIS FRIDAY EVENING... VERY STRONG THUNDERSTORM ARE EXPECT TO DEVELOP OVER PORTIONS OF EASTERN WYOMING THE REST OF THE AFTERNOON AND EVENING. A FEW OF THESE STORMS COULD PRODUCE BRIEF HEAVY RAIN AND HAIL. A TORNADO IS POSSIBLE WITH ONE OF THESE STORMS. THE MOST LIKELYHOOD OF SEVERE WEATHER IS IN NIOBRARA...GOSHEN...LARAMIE OR EASTERN PLATTE COUNTY. A TORNADO WATCH HAS BEEN POSTED FOR THE EASTERN COUNTIES AND INCLUDE THE FOLLOWING CITIES IN THE WATCH AREA...TORRINGTON...LUSK...CHEYENNE AND PINE BLUFFS. NEAR 245 PM A STRONG THUNDERSTORM WAS NOTED ON RADAR IN SOUTHWESTERN GOSHEN COUNTY MOVING TO THE NORTH AT NEARLY 30 MILES AN HOUR. SGS
Special weather statement, May 10, 3:28 PM MDT, 3 hours 1 minute before
WYZ012-017-110035- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 325 PM MDT FRI MAY 10 1991 ...A TORNADO WATCH HAS BEEN ISSUED FOR EXTREME EASTERN WYOMING UNTIL 9 PM THIS FRIDAY EVENING... A LINE OF THUNDERSTORMS WAS LOCATED BY WEATHER RADAR IN NORTHERN LARAMIE COUNTY AND IN SOUTHWEST GOSHEN COUNTY FRIDAY AFTERNOON. HAILSTONES UP TO ONE HALF INCH WERE REPORTED FROM ONE OF THESE STORMS AROUND 3 PM. THE LOCATION OF THE SMALL HAIL WAS 28 MILES NORTHEAST OF CHEYENNE. RADAR CONTINUED TO NOTED SCATTERED SHOWERS AND THUNDERSTORMS IN SOUTHEAST WYOMING MOVING TO THE NORTH AT NEARLY 30 MILES AN HOUR. SGS
Special weather statement, May 10, 5:41 PM MDT, 48 minutes before
WYZ012-017-110100- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 440 PM MDT FRI MAY 10 1991 ...A TORNADO WATCH CONTINUES IN EFFECT FOR EXTREME EASTERN WYOMING UNTIL 9 PM THIS EVENING... THUNDERSTORMS CONTINUED OVER THE SOUTHEAST CORNER OF WYOMING LATE THIS AFTERNOON. THE STRONGEST STORMS WERE ALONG INTERSTATE 25 HEADING NORTH FROM CHEYENNE. A PILOT OBSERVED A POSSIBLE FUNNEL CLOUD ABOUT 30 TO 35 MILES NORTH OF CHEYENNE. RADAR INDICATED THESE STORMS WERE LIKELY PRODUCING SMALL HAIL AS WELL. THE THUNDERSTORMS THAT PRODUCED GOLF-BALL SIZE HAIL IN THE TORRINGTON AREA EARLIER HAD MOVED NORTHEAST INTO NEBRASKA. STRONG THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE OVER SOUTHEAST WYOMING THIS EVENING. A TORNADO WATCH FOR THE EXTREME EAST WILL CONTINUE UNTIL 9 PM TONIGHT. PEOPLE IN SOUTHEAST WYOMING SHOULD BE ALERT FOR THUNDERSTORM ACTIVITY THIS EVENING AND TAKE SHELTER IF THUNDERSTORMS APPROACH. LISTEN TO NOAA WEATHER RADIO OR THE LOCAL MEDIA FOR ADDITIONAL INFORMATION ON THE STORMS. SCOTT
Special weather statement, May 10, 5:42 PM MDT, 47 minutes before
WYZ012-017-110100- SPECIAL WEATHER STATEMENT...CORRECTED FOR TIME NATIONAL WEATHER SERVICE CHEYENNE WY 540 PM MDT FRI MAY 10 1991 ...A TORNADO WATCH CONTINUES IN EFFECT FOR EXTREME EASTERN WYOMING UNTIL 9 PM THIS EVENING... THUNDERSTORMS CONTINUED OVER THE SOUTHEAST CORNER OF WYOMING LATE THIS AFTERNOON. THE STRONGEST STORMS WERE ALONG INTERSTATE 25 HEADING NORTH FROM CHEYENNE. A PILOT OBSERVED A POSSIBLE FUNNEL CLOUD ABOUT 30 TO 35 MILES NORTH OF CHEYENNE. RADAR INDICATED THESE STORMS WERE LIKELY PRODUCING SMALL HAIL AS WELL. THE THUNDERSTORMS THAT PRODUCED GOLF-BALL SIZE HAIL IN THE TORRINGTON AREA EARLIER HAD MOVED NORTHEAST INTO NEBRASKA. STRONG THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE OVER SOUTHEAST WYOMING THIS EVENING. A TORNADO WATCH FOR THE EXTREME EAST WILL CONTINUE UNTIL 9 PM TONIGHT. PEOPLE IN SOUTHEAST WYOMING SHOULD BE ALERT FOR THUNDERSTORM ACTIVITY THIS EVENING AND TAKE SHELTER IF THUNDERSTORMS APPROACH. LISTEN TO NOAA WEATHER RADIO OR THE LOCAL MEDIA FOR ADDITIONAL INFORMATION ON THE STORMS. SCOTT
The office that day
Everything else NWS Cheyenne, WY issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 10, 6:03 PM MDT | Flash Flood Warning | CYS | Dawes, Sioux | 4 hr |
| May 10, 6:33 PM MDT | Severe Thunderstorm Warning | CYS | Dawes, Sioux | 57 min |
| May 10, 7:34 PM MDT | Severe Thunderstorm Warning | CYS | Sioux | 56 min |
| May 10, 8:33 PM MDT | Severe Thunderstorm Warning | CYS | Sioux | 57 min |
| May 10, 9:35 PM MDT | Severe Thunderstorm Warning | CYS | Dawes, Sioux | 55 min |
| May 10, 9:58 PM MDT | Flash Flood Warning | CYS | Dawes, Sioux | 4 hr |
| May 11, 3:46 PM MDT | Severe Thunderstorm Warning | CYS | Sioux | 59 min |
| May 11, 4:48 PM MDT | Severe Thunderstorm Warning | CYS | Sioux | 27 min |
| May 11, 5:41 PM MDT | Severe Thunderstorm Warning | CYS | Sioux | 34 min |
| May 11, 5:56 PM MDT | Severe Thunderstorm Warning | CYS | Banner, Morrill | 64 min |
| May 10, 7:00 PM MDT | Severe Thunderstorm Warning | CYS | Goshen, Platte | 45 min |
Nearby
Severe Thunderstorm Warnings in Wyoming, 1991Every severe thunderstorm warning in 1991
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.