Alert archive / Wyoming / Severe Thunderstorm Warnings in 2002
Severe Thunderstorm Warning 89, NWS Rapid City, SD
NWS Rapid City, SD issued this severe thunderstorm warning at Jul 27, 2002, 7:06 PM MDT for Campbell County, Wyoming. It was in force for 39 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
- Jul 27, 2002, 7:06 PM MDT (01:06 UTC)
- Expired
- Jul 27, 2002, 7:45 PM MDT
- In force
- 39 min
- Issued by
- NWS Rapid City, SD
- Area
- Counties, with a storm outline in the text
County Campbell County, WY
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 27, 7:10 PM MDT | Thunderstorm Wind 60 M | Echeta, 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
Rapid City, SD (KUNR), launched 00:00Z, 1.1 hours before the alert went out and 214 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
- 220 J/kg
- Mixed-layer CIN
- -16 J/kg
- Mixed-layer LCL
- 2793 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km storm-relative helicity
- 28 m²/s²
- 0-3 km storm-relative helicity
- 95 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
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 Rapid City, SD wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 27, 1:15 PM MDT, 5 hours 51 minutes earlier.
Area forecast discussion, Jul 27, 1:15 PM MDT, 5 hours 51 minutes before
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 115 PM MDT SAT JUL 27 2002 THE MAIN WEATHER OF INTEREST IS THE RELATIVELY STRONG TROUGH THAT WILL PASS THROUGH THE CWFA TONIGHT AND SUNDAY...BRINGING A DECENT CHANCE OF PRECIPITATION TO MUCH OF THE AREA. THE MAIN PART OF THIS WAVE WAS MOVING THROUGH ID EARLY THIS AFTERNOON...WITH THUNDERSTORMS EVIDENT OVER CENTRAL MT. IN ADVANCE OF THIS FEATURE...NORTHWEST WINDS HAVE BROUGHT SOME DRIER BOUNDARY-LAYER AIR INTO THE CWFA... BUT SURFACE PRESSURE FALLS HAVE RECENTLY DEVELOPED IN WY...SO IT IS EXPECTED THAT THE FLOW WILL BEGIN TO TURN MORE NORTH-NORTHEAST IN THE LATE AFTERNOON/EARLY EVENING TIME-FRAME. THIS SHOULD ADVECT A LITTLE MORE BOUNDARY-LAYER MOISTURE BACK INTO THE CWFA...SETTING THE STAGE FOR SHOWERS AND THUNDERSTORMS OVERNIGHT. THE SHEAR WILL BE MORE THAN SUFFICIENT FOR SUPERCELLS OVER THE NORTHERN CWFA...BUT DRY LOW-LEVELS AND WEAK INSTABILITY MAY PREVENT SUSTAINED UPDRAFTS FROM DEVELOPING. AT ANY RATE...THE COVERAGE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO BE 40-60 PERCENT TONIGHT GIVEN THE STRONG UPPER-LEVEL FORCING...LOW-LEVEL FRONTOGENESIS...AND INCREASING MOISTURE. THE BEST CHANCE FOR PRECIPITATION WILL BE ACROSS THE NORTH. THE TROUGH WILL FINISH MOVING THROUGH THE CWFA ON SUNDAY. A COLD POCKET OF AIR AT 500 MB SHOULD RESULT IN ENOUGH INSTABILITY FOR A FEW SHOWERS ACROSS THE CWFA...WITH A LITTLE BETTER CHANCE FARTHER EAST CLOSER TO THE STRONG FORCING. A FEW SHOWERS MAY LINGER IN SOUTH-CENTRAL SD SUNDAY EVENING...BUT THEN QUIET WEATHER WILL RETURN SUNDAY NIGHT THROUGH MONDAY. A WEAK UPPER-LEVEL WAVE AND SURFACE FRONT ARE ADVERTISED TO MOVE ACROSS THE CWFA TUESDAY NIGHT AND WEDNESDAY MORNING...BUT AT THIS TIME IT DOESNT APPEAR THAT THERE WILL BE ENOUGH LOW-LEVEL MOISTURE TO MENTION ANY PRECIPITATION. THE NEXT CHANCE OF THUNDERSTORMS WILL BE WEDNESDAY NIGHT AND THURSDAY AS A SERIES OF WAVES MOVE ACROSS THE CWFA IN A ZONAL FLOW. THE EXTENDED MODELS AGREE ON A FLAT RIDGE DEVELOPING OVER THE CENTRAL UNITED STATES ON FRIDAY AND SATURDAY...WITH SOUTHWEST FLOW OVER MOST OF THE CWFA. THIS PATTERN LOOKS CONDUCIVE TO SOME THUNDERSTORMS OVER THE NORTH...BUT THE SOUTH IS EXPECTED TO BE CAPPED. .UNR...NONE BUNKERS
The office that day
Everything else NWS Rapid City, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 27, 8:31 PM MDT | Severe Thunderstorm Warning | UNR | Butte | 74 min |
| Jul 27, 9:25 PM MDT | Severe Thunderstorm Warning | UNR | Harding | 35 min |
| Jul 27, 9:32 PM MDT | Severe Thunderstorm Warning | UNR | Perkins | 73 min |
| Jul 27, 9:40 PM MDT | Severe Thunderstorm Warning | UNR | Butte | 35 min |
| Jul 27, 7:20 PM MDT | Severe Thunderstorm Warning | UNR | Crook | 55 min |
| Jul 27, 8:14 PM MDT | Severe Thunderstorm Warning | UNR | Crook | 61 min |
Nearby
Severe Thunderstorm Warnings in Wyoming, 2002Every severe thunderstorm warning in 2002
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.