Hot and dry conditions were ideal for thunderstorm microburst outflow propagation across Southeast Oregon and Southwest Idaho. Severe gusts were reported with reports of damage throughout the area.
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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.
The episode as NWS BOI wrote it up.
Hot and dry conditions were ideal for thunderstorm microburst outflow propagation across Southeast Oregon and Southwest Idaho. Severe gusts were reported with reports of damage throughout the area.
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 Boise, ID wrote its last area forecast discussion before the first event at Jun 22, 1:49 PM MST, 5 hours 1 minute earlier.
Area Forecast Discussion
National Weather Service Boise ID
249 PM MDT Tue Jun 22 2021
.SHORT TERM...Tonight through Thursday night...A vigorous
shortwave over NW NV and southcentral OR will move into SW Idaho
this evening. Showers and storms have been going all morning in
south central OR and will slowly move northeastward over the day.
A cold pool has developed over east-central Oregon near Burns with
temperatures currently in the 70s. This cold pool combined with
the hot conditions in extreme eastern OR and southwest Idaho will
enhance a pressure gradient over the region this afternoon and
evening. There is enough CAPE and shear to support thunderstorms
this afternoon and evening. The stronger storms in Oregon will
produce hail but the lower atmospheric levels will be so warm that
large hail is unlikely to reach the ground. Where temperatures
have reached into the 90s this afternoon, inverted-V soundings and
DCAPE values of 1500-2000j/kg have developed, which will be
favorable for wind gusts up to 60 mph with showers and storms that
do form. A high wind watch remains in effect from 5pm to 10pm
MDT to highlight the wind gust potential this afternoon and
evening. Blowing dust, wind gusts up to 60 mph possible across
much of southwest Idaho and extreme eastern OR this evening. Things
quiet down after midnight tonight. More showers and thunderstorms
expected on Wednesday and again on Thursday, mainly along the NV
border to the Owyhee Mountains with gusty winds possible during
the afternoons.
.LONG TERM...Friday through Tuesday...Hot and dry. A large and very
warm upper level high pressure ridge centered over the B.C. coast on
Friday will remain over southwest Canada and the northwest U.S.
through Tuesday. Many locations will see near-record to record heat
over the weekend and into early next week, with highs around 20
degrees above normal.
&&
.AVIATION...VFR. scattered showers and thunderstorms in eastern
Oregon spreading into southwest Idaho and the central Idaho
mountains by 00z/Wed, ending after 06z/Wed. Gusty outflow winds 40-
50 kts and blowing dust possible near thunderstorms. Surface winds:
northwest 20-35 kts eastern Oregon spreading across southwest
Idaho after 00z/Wed, decreasing to 5-15 kts after 06z/Wed. Winds
aloft at 10k ft MSL: south to southwest 10-20 kts, becoming west
20-30 kts after 06z/Wed. Hot temperatures this week will lead to
increased density altitude.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...High Wind Watch until 10 PM MDT this evening
IDZ011>016-028>030-033.
Fire Weather Watch from Wednesday afternoon through Wednesday
evening IDZ423-426.
OR...High Wind Watch until 10 PM MDT /9 PM PDT/ this evening
ORZ062>064.
Fire Weather Watch from Wednesday afternoon through Wednesday
evening ORZ637.
Red Flag Warning until midnight MDT /11 PM PDT/ tonight
ORZ636-637-646.
&&
www.weather.gov/Boise
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SHORT TERM...KA
LONG TERM....JT
AVIATION.....JTPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BOISE ID
727 PM MDT TUE JUN 22 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0710 PM DUST STORM GREENLEAF 43.67N 116.82W
06/22/2021 CANYON ID TRAINED SPOTTER
REPORTS FROM A TRAINED SPOTTER OF DOWNED TREES, BROKEN
BRANCHES, AND REDUCED VISIBILITIES DUE TO BLOWING DUST -
LESS THAN 1 MILE - ASSOCIATED WITH A STRONG OUTFLOW
BOUNDARY RAPIDLY PUSHING THROUGH THE AREA.
&&
WASYL.HEWKOPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BOISE ID
735 PM MDT TUE JUN 22 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0730 PM DUST STORM 4 SSW OREANA 43.00N 116.38W
06/22/2021 OWYHEE ID TRAINED SPOTTER
A TRAINED SPOTTER REPORTS GUSTY WINDS ESTIMATED AT 35 MPH
WITH BLOWING DUST REDUCING VISIBILITY AS LOW AS 1/2 MILE.
&&
WASYL.HEWKOThe Boise radar (KCBX), 86 km away, was scanning. The volume nearest the first event began at 01:47 UTC.
1 thunderstorm wind. Local standard time, as filed.
The ASOS at Ontario reported a 62 MPH thunderstorm wind gust.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2021Every state in 2021This day in weather historyWarnings in Oregon, June 2021
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: 974825.