Alert archive / Wyoming / Severe Thunderstorm Warnings in 2002
Severe Thunderstorm Warning 121, NWS Billings, MT
NWS Billings, MT issued this severe thunderstorm warning at Aug 21, 2002, 6:51 PM MDT for Sheridan County, Wyoming. It was in force for 54 min. 2 reports 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
- Aug 21, 2002, 6:51 PM MDT (00:51 UTC)
- Expired
- Aug 21, 2002, 7:45 PM MDT
- In force
- 54 min
- Issued by
- NWS Billings, MT
- Area
- Whole counties
County Sheridan County, WY
The radar
The Billings radar (KBLX), 180 km from the middle of the area, began a volume at 00:54 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 |
|---|---|---|---|
| Aug 21, 6:54 PM MDT | Hail 0.88 | Wyarno, WY | Report also of 2.35 inches of rain |
| Aug 21, 7:18 PM MDT | Hail 0.75 | Clearmont, 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
Riverton, WY (KRIW), launched 00:00Z, 0.9 hours before the alert went out and 227 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
- 39 J/kg
- Mixed-layer CIN
- -4 J/kg
- Mixed-layer LCL
- 2959 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km storm-relative helicity
- 44 m²/s²
- 0-3 km storm-relative helicity
- 96 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 Billings, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 21, 2:33 PM MDT, 4 hours 18 minutes earlier.
Area forecast discussion, Aug 21, 2:33 PM MDT, 4 hours 18 minutes before
SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE BILLINGS MT
ISSUED BY GLASGOW MT NWS
156 PM MDT WED AUG 21 2002
.SHORT TERM...VALID FOR THU AND FRI..
SEVERE WEATHER THREAT WILL CONTINUE TO BE THE PRIMARY FOCUS OF THE SHORT
TERM. UPPER LEVEL LOW POSITIONED ALONG THE OREGON/IDAHO BORDER WILL
CONTINUE TO EJECT SHORT WAVES ACROSS THE CWA OVER THE NEXT 48 HOURS.
THE FIRST OF THESE WAVES IS PRODUCING THUNDERSTORMS OVER NORTHWEST
WYOMING. STRONG UPPER LEVEL DIVERGENCE ACROSS THE REGION WILL AID IN
STRONG THUNDERSTORM DEVELOPMENT. WHILE STRONGEST CAPE CONTINUES TO
BE FORECASTED ACROSS THE EASTERN HALF OF THE CWA...THE BEST DYNAMICS
SHOULD BE OVER THE SOUTH CENTRAL AND SOUTHWESTERN PORTIONS OF CWA.
UPPER LEVEL LOW REMAINS PARKED IN PLACE ON THURSDAY AND BEGINS TO
RETROGRADE A BIT ON THURSDAY NIGHT. MESO-ETA PRODUCING WIDESPREAD
QPF THROUGH THE PERIOD. SOUTHWEST FLOW REMAINS IN PLACE ACROSS THE
CWA INTO THE WEEKEND WITH WEAK WAVES BEING EJECTED FROM PACIFIC
NORTHWEST LOW. WILL CONTINUE SCATTERED POPS ACROSS THE REGION
TONIGHT. WITH BEST CHANCE OF DEVELOPMENT OVER THE WESTERN HALF OF
CWA...WILL DROP POPS OVER THE EAST A NOTCH. CURRENTLY FORECASTED
TEMPERATURES LINE UP WELL WITH MOS GUIDANCE AND SEE NO REASON TO
MAKE DRASTIC CHANGES.
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
UNSETTLED PATTERN WILL REMAIN IN PLACE FOR A LARGE PORTION OF THE
EXTENDED PERIOD. MRF CONTINUES TO KEEP AN ELONGATED TROUGH ACROSS
THE REGION WHILE THE ECMWF IS A BIT MORE PROGRESSIVE. WILL CONTINUE
CURRENT TREND TOWARD THE END OF THE PERIOD WITH TEMPERATURES
REMAINING NEAR NORMAL. POHL
THU FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 056/085 054/084 052/086 054/086 053/083 051/082 050/083
43/T 33/T 33/T 33/T 30/E 00/B 00/B
LVM 051/081 050/082 048/083 048/084 047/081 045/080 045/081
43/T 33/T 33/T 33/T 30/E 00/B 00/B
HDN 055/087 052/087 050/088 052/088 050/085 048/084 047/084
43/T 33/T 33/T 33/T 30/E 00/B 00/B
MLS 058/086 056/085 055/087 057/087 056/083 054/082 053/083
32/T 33/T 33/T 33/T 30/E 00/B 00/B
4BQ 056/085 055/084 054/086 056/086 055/082 053/081 053/081
32/T 33/T 33/T 33/T 30/E 00/B 00/B
BHK 055/083 053/083 052/084 053/084 053/080 051/079 050/079
32/T 33/T 33/T 33/T 30/E 00/B 00/B
SHR 053/084 051/084 051/085 050/084 049/080 047/079 046/079
43/T 33/T 33/T 33/T 30/E 00/B 00/B
.BYZ...
MT...NONE.
WY...NONE.In the hours before
Local storm report, Aug 21, 1:15 PM MDT, 5 hours 36 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS, MT
115 PM MDT WED AUG 21 2002
TIME(MDT) .....CITY LOCATION.....STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
1005 AM 3 N MILES CITY MT .75 INCH HAIL
08/21/02 CUSTER
JZThe office that day
Everything else NWS Billings, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 6:03 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 57 min |
| Aug 22, 3:56 PM MDT | Severe Thunderstorm Warning | BYZ | Sweet Grass, Wheatland | 64 min |
| Aug 22, 4:13 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 62 min |
| Aug 22, 5:10 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 65 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; radar from the NEXRAD Level II archive.