Hail and Heavy Rain in Wyoming, August 21, 2002

Name: Hail and Heavy Rain in Wyoming, August 21, 2002
Start: 2002-08-21T16:45
End: 2002-08-21T18:18
Location: Wyoming

August 21, 2002 · NWS BYZ · 5 events in 1 county or zone

4 hail, 1 heavy rain, as filed by the National Weather Service.

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 5

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What forecasters said that day

The local office's own words before the first event, 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 the first event at Aug 21, 1:33 PM MST, 3 hours 12 minutes earlier.

Area forecast discussion, Aug 21, 1:33 PM MST, 3 hours 12 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, 12:15 PM MST, 4 hours 30 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

JZ

The radar

The Billings radar (KBLX), 153 km away, was scanning. The volume nearest the first event began at 23:46 UTC.

Open the radar archive at this moment

Event by event

4 hail, 1 heavy rain. Local standard time, as filed.

Hail, Sheridan

When: August 21, 4:45 PM MST
Where: Sheridan County, Ranchester
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 44.917, -107.167

Hail, Sheridan

When: August 21, 5:04 PM MST
Where: Sheridan County, Sheridan
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 44.800, -106.950

Ground whitened by hail

Hail, Sheridan

When: August 21, 5:54 PM MST
Where: Sheridan County, 4 mi W of Wyarno
Measured: 0.88 in hail
Reported by: TRAINED SPOTTER
Coordinates: 44.817, -106.850

Report also of 2.35 inches of rain

Heavy Rain, Sheridan

When: August 21, 5:55 PM MST
Where: Sheridan County, Sheridan
Reported by: LAW ENFORCEMENT
Coordinates: 44.790, -106.879 (the zone’s center; the record gives no point)

1.50 inches of rain in 45 minutes. Some street flooding briefly occurred but receded quickly.

Hail, Sheridan

When: August 21, 6:18 PM MST
Where: Sheridan County, 1 mi W of Clearmont
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 44.633, -106.400

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Heavy Rain: Rainfall totals unusual for the place and season that did not produce a flood.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Wyoming in 2002 Every state in 2002 This day in weather history Warnings in Wyoming, August 2002

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5314976, 5314977, 5314978, 5314979, 5314980.