On July 9th, an upper level low tracked northeast across southwest Idaho aiding in thunderstorm development. With a dry boundary layer, and marginal precipitable water values, outflow winds were the primary hazard with burn scar flooding a secondary hazard.
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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.
On July 9th, an upper level low tracked northeast across southwest Idaho aiding in thunderstorm development. With a dry boundary layer, and marginal precipitable water values, outflow winds were the primary hazard with burn scar flooding a secondary hazard.
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 Jul 9, 2:58 AM MST, 2 hours 32 minutes earlier.
Area Forecast Discussion
National Weather Service Boise ID
358 AM MDT Wed Jul 9 2025
.SHORT TERM...Today through Friday night...Water vapor satellite
imagery showing an upper low centered over northern CA tonight.
Showers and thunderstorms will develop out ahead of the low
as it tracks through SE Oregon and SW Idaho this afternoon. The
higher thunderstorm probability will stretch from central
Harney and Malheur counties in Oregon into southwest Idaho from
the Boise mtns to the NV border. Outflow winds will be the main
threat from storms with gusts up to 60 mph possible from
Malheur County eastward through the Snake Plain and Boise mtns.
While not all locations will see winds this strong, a broad area
of 35 to 50 mph winds is looking more likely across northern
Malheur County, the Weiser Basin, Treasure Valley and
W-Central/Boise mtns. Blowing dust will accompany the winds as
well, especially at lower elevations. This system isn't
particularly wet (PW values in the 50-60 %tile) with majority of
high res models showing 0.25-0.50"/hr rainfall. While these
amounts aren't generally a flood concern, will need to keep an
eye on burn scars, especially the Wapiti, which carry lower
thresholds for flood/debris potential. The chance for
thunderstorms carries through sunset for most locations,
lingering through midnight in the Boise mtns. Biggest changes to
the forecast tonight were to increase thunderstorm chances to
30-40% in area where strong outflow winds are more likely (which
also matches up with SPC's area of Marginal Risk).
Thursday and Friday will see a return to dry weather under
weak troughing in NW flow. Temperatures both days will be at or
slightly below normal. Daytime mixing will bring breezy
conditions on Thursday with gusts of 25-35 mph in Snake Plain
east of Boise.
.LONG TERM...Saturday through Wednesday...A strong ridge of high
pressure is expected to slowly build into the area off the
California coast over the weekend, returning a warming and
drying trend from Saturday to early next week. Valley daytime
temperatures are expected to reach the mid to upper 90s Saturday
and Sunday, and close to 100 on Monday. Long-term guidances
generally project an upper trough sweeping across the northwest
region, but precipitation is not hinted by this system.
Wednesday will see a ridge build into the area on top of the
large high pressure system over the desert southwest, continuing
very warm and dry conditions.
&&
.AVIATION...Mainly VFR under few high clouds overnight and early
morning. Isolated to scattered showers and thunderstorms will
develop across the area Wednesday afternoon/early evening. Gusts
up to 50 kt and blowing dust reducing visibility will be
possible. Surface winds: W-NW 5-15 kt through morning and early
afternoon. Winds aloft at 10kft MSL: S-SW 5-15 kt.
KBOI...VFR through early morning. Surface winds: variable less
than 7 kt overnight and early morning. Winds NW 5-15 kt with
gusts to 20 kt Wednesday afternoon.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning from 3 PM this afternoon to midnight MDT
tonight IDZ400-420-423-424-426.
OR...Red Flag Warning from 3 PM MDT /2 PM PDT/ this afternoon to
midnight MDT /11 PM PDT/ tonight ORZ670-672>674.
&&
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SHORT TERM...DG
LONG TERM....JY
AVIATION.....JYThe Boise radar (KCBX), 38 km away, was scanning. The volume nearest the first event began at 12:31 UTC.
3 thunderstorm wind. Local standard time, as filed.
At 6:30pm MDT, Idaho Power mesonet station 032ID recorded a wind gust of 68 mph. Later, at 6:36pm MDT, a RAWs (LLCI1) recorded a gust of 59 mph. These gusts were associated with a outflow boundary from a thunderstorm southwest of both locations. No damages were reported.
Mesonet station IDARNG2_RG14 measured a wind gust of 63 mph as a thunderstorm outflow passed. This outflow continued into Elmore county. No damages were reported.
Continuation of outflow boundary originating from Ada County. Mesonet station IDARNG3_D2 measured a wind gust of 58 mph. No damages reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2025Every state in 2025This day in weather historyWarnings in Idaho, July 2025
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: 1281137, 1280941, 1280942.