On May 28th, an upper low was over the Great Basin. A shortwave propagating around this low helped prime the atmosphere for thunderstorm development.
Every event with a place to put it. Tap one for its entry below.
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 May 28th, an upper low was over the Great Basin. A shortwave propagating around this low helped prime the atmosphere for thunderstorm development. A dry, well-mixed boundary layer was present over far southwest Idaho leading to a severe wind threat. Further north into the west central Idaho mountains, effective shear was to 30-40 knots. This increased the hail threat north, in addition to the wind.
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 May 28, 2:09 PM MST, 19 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Boise ID 309 PM MDT Thu May 28 2026 .KEY MESSAGES... - Strong to severe thunderstorms today capable of wind gusts to 70 mph, blowing dust, hail, and heavy rain, with the highest potential across southeast Oregon and the west-central Idaho mountains. - Breezy south winds this afternoon with gusts 50 mph in southern Twin Falls County. - Showers and weaker thunderstorms persist on Friday, then decrease on Saturday with mostly dry conditions returning next week. - Temperatures cool to slightly below normal on Saturday, then warm to 10-15 degrees above normal by the middle of next week. && .SHORT TERM /Through Saturday Night/... Impressive severe weather setup over the region this afternoon, with large hail and strong winds possible. A trough remains over western NV today with a shortwave moving north along the NV border this afternoon. Favorable dynamics aloft for severe weather today across eastern OR and southwest ID along the OR border. A severe thunderstorm watch has been issued for large hail up to 2 inches in diameter, mainly across eastern OR and strong to severe outflow winds across southwest Idaho. At the time of this writing, a storm east of Burns OR was producing radar estimated 2-3 inch hail. Wind gusts up to 60-80 mph possible with the stronger storms in eastern OR and southwest ID from the Owyhees north through the Treasure Valley and Weiser Basin this evening. The storms and associated gust front should move through Boise metro around 4 to 6pm MDT and move north and west toward 5 to 7pm PDT in Baker. Storm threat will quickly dissipate from south to north after this wave moves through and diminishes after sunset. Quieter conditions expected on Friday with showers and thunderstorms lingering over the west central ID mountains. Saturday will be the coolest day of the period as the trough slowly moves east into Montana, with showers lingering over the west central ID mountains. && .LONG TERM /Sunday through Thursday/... Come Sunday, there is greater long-range guidance agreement on the upper low merged with a Pacific longwave trough steering northeast of our area over Montana. This pattern shift will begin a warming and drying trend Sunday through the end of the extended period. Temperatures on Sunday will sit right around normal, warming to 10-15 degrees above normal by Wednesday. Long-range projections hint at a weak and mostly dry shortwave trough digging over over our area late Wednesday into Thursday. For now, Thursday will most likely see dry conditions and above normal temperatures. && .AVIATION /18Z Thursday through Friday/... Issued 1109 AM MDT THU MAY 28 2026 Generally VFR. Scattered showers and thunderstorms developing early this afternoon, with the strongest storms in eastern OR and southwest ID. Storms will be capable of strong outflows of 50-60 kt, hail, blowing dust, and brief heavy rain. Showers and thunder tapering off in the evening around sunset. Surface winds outside of storms: SW- SE 10-20 kt with gusts to 20-35 kt this afternoon. Winds aloft at 10kft MSL: E-SE 15-30 kt. KBOI...VFR. A 15-20% chance of thunder at the terminal this afternoon 21z-Fri/00z. Thunder capable of brief heavy rain, small hail, and outflows up to 50-60 kt. Strong outflows may travel from distant storms further south. Surface winds outside of storms: S-SE 10-15 kt with gusts to 25 kt this afternoon. Weekend Outlook...Generally VFR. Scattered rain showers and isolated thunderstorms Friday. Showers and thunderstorms mainly over the central ID mountains on Saturday. Then generally dry Sunday. Gusty erratic winds and brief heavy rain in storms. Surface winds: W-NW 5-15 kt each day with afternoon gusts to 20-25 kt, except W-NW 10-20 kt with afternoon gusts to 30-35 kt near KMUO/KTWF/KJER. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Wind Advisory until 7 PM MDT this evening for IDZ030. OR...None. && www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise SHORT TERM...KA LONG TERM....JY AVIATION.....JY
Special Weather Statement
National Weather Service Boise ID
1207 PM PDT Thu May 28 2026
ORZ063-282000-
Malheur County OR-
1207 PM PDT Thu May 28 2026
...A STRONG THUNDERSTORM WILL IMPACT WEST CENTRAL MALHEUR COUNTY
THROUGH 100 PM PDT...
At 1207 PM PDT, Doppler radar was tracking a strong thunderstorm near
Scott Reservoir, or 8 miles south of Rome, moving west at 30 mph.
HAZARD...Wind gusts of 50 to 55 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Areas of blowing dust reducing
visibility. Minor damage to outdoor objects is possible.
This strong thunderstorm will be near...
Scott Reservoir around 110 PM MDT.
Burns Junction around 130 PM MDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4277 11736 4261 11759 4270 11818 4302 11790
TIME...MOT...LOC 1907Z 107DEG 26KT 4271 11759
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH
KASpecial Weather Statement
National Weather Service Boise ID
1245 PM PDT Thu May 28 2026
ORZ061-282030-
Harney County OR-
1245 PM PDT Thu May 28 2026
...A STRONG THUNDERSTORM WILL IMPACT WEST CENTRAL HARNEY COUNTY
THROUGH 130 PM PDT...
At 1245 PM PDT, Doppler radar was tracking a strong thunderstorm over
Stinking Lake, or 22 miles southwest of Burns, moving west at 10 mph.
HAZARD...Wind gusts of 50 to 55 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Areas of blowing dust reducing
visibility. Minor damage to outdoor objects is possible.
This strong thunderstorm will be near...
Stinking Lake around 1250 PM PDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 4343 11921 4325 11922 4319 11962 4349 11963
TIME...MOT...LOC 1945Z 089DEG 11KT 4333 11932
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH
NFSpecial Weather Statement
National Weather Service Boise ID
1248 PM PDT Thu May 28 2026
ORZ061-063-282030-
Malheur County OR-Harney County OR-
1248 PM PDT Thu May 28 2026
...STRONG THUNDERSTORMS WILL IMPACT EAST CENTRAL HARNEY AND WEST
CENTRAL MALHEUR COUNTIES THROUGH 130 PM PDT...
At 1247 PM PDT, Doppler radar was tracking strong thunderstorms along
a line extending from 7 miles northwest of Owyhee Butte to near Flat
Top Mountain. Movement was west at 35 mph.
HAZARD...Wind gusts of 50 to 55 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Areas of blowing dust reducing
visibility. Minor damage to outdoor objects is possible.
Strong thunderstorms will be near...
Burns Junction, Flat Top Mountain, and Saddle Butte Lava Tube
around 150 PM MDT.
Antelope Spring and Saddle Butte around 200 PM MDT.
Table Mountain around 110 PM PDT.
Ryegrass Butte and Turnbull Peak around 210 PM MDT.
Coffin Butte, Heath Lake, Juniper Lake, and Tencent Lake around
120 PM PDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
A Severe Thunderstorm Watch remains in effect until 800 PM PDT for
southeastern Oregon.
&&
LAT...LON 4324 11824 4267 11851 4267 11788 4308 11770
TIME...MOT...LOC 1947Z 101DEG 32KT 4303 11774 4271 11789
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH
NFSpecial Weather Statement
National Weather Service Boise ID
217 PM MDT Thu May 28 2026
IDZ011-282100-
West Central Mountains ID-
217 PM MDT Thu May 28 2026
...A STRONG THUNDERSTORM WILL IMPACT WEST CENTRAL VALLEY AND EAST
CENTRAL ADAMS COUNTIES THROUGH 300 PM MDT...
At 217 PM MDT, Doppler radar was tracking a strong thunderstorm near
Donnelly, or 9 miles south of McCall, moving north at 20 mph.
HAZARD...Wind gusts up to 50 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Areas of blowing dust reducing
visibility. Minor damage to outdoor objects is possible.
This strong thunderstorm will be near...
McCall around 230 PM MDT.
Payette Lake and Little Payette Lake around 240 PM MDT.
Meadows and Brundage Ski Area around 250 PM MDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
If on or near Payette Lake, get out of the water and move indoors or
inside a vehicle. Remember, lightning can strike out to 10 miles
from the parent thunderstorm. If you can hear thunder, you are close
enough to be struck by lightning. Move to safe shelter now! Do not
be caught on the water in a thunderstorm.
A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
southwestern Idaho.
&&
LAT...LON 4473 11591 4467 11615 4502 11644 4511 11603
TIME...MOT...LOC 2017Z 160DEG 17KT 4478 11607
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH
KASpecial Weather Statement
National Weather Service Boise ID
231 PM MDT Thu May 28 2026
IDZ012-014-015-029-282115-
Upper Treasure Valley ID-Lower Treasure Valley ID-
Southwest Highlands ID-Owyhee Mountains ID-
231 PM MDT Thu May 28 2026
...STRONG THUNDERSTORMS WILL IMPACT SOUTHEASTERN ADA...SOUTHWESTERN
ELMORE AND CENTRAL OWYHEE COUNTIES THROUGH 315 PM MDT...
At 231 PM MDT, Doppler radar was tracking a cluster of strong
thunderstorms along a line extending from 6 miles southwest of Black
Warrior Mountain to near Twentymile Butte. Movement was north at 15
mph.
HAZARD...Wind gusts of 50 to 55 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Areas of blowing dust reducing
visibility.
Locations impacted include...
Mountain Home, Mountain Home Air Force Base, Grand View, Reynolds,
Silver City, Bruneau, Winter Camp Butte, Hinton Reservoir, Lookout
Butte, Triangle, Toy Pass, Pot Hole Butte, Black Warrior Mountain,
The Hat, Succor Creek Reservoir, Mud Flat Spring, Oreana, Crab Spring
Butte, Chalk Hills, and Gedney Butte.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
southwestern Idaho.
&&
LAT...LON 4322 11698 4310 11552 4243 11544 4256 11680
TIME...MOT...LOC 2031Z 177DEG 15KT 4285 11686 4274 11513
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH
JYSpecial Weather Statement
National Weather Service Boise ID
258 PM MDT Thu May 28 2026
IDZ011-033-ORZ062-282145-
West Central Mountains ID-Upper Weiser River ID-Baker County OR-
258 PM MDT Thu May 28 2026
...A STRONG THUNDERSTORM WILL IMPACT WEST CENTRAL VALLEY...ADAMS...
NORTHERN WASHINGTON AND NORTHEASTERN BAKER COUNTIES THROUGH 345 PM
MDT/245 PM PDT/...
At 258 PM MDT/158 PM PDT/, Doppler radar was tracking a strong
thunderstorm over Tamarack, or 13 miles west of McCall, moving
northwest at 65 mph.
HAZARD...Wind gusts of 50 to 55 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Areas of blowing dust reducing
visibility. Minor damage to outdoor objects is possible.
This strong thunderstorm will be near...
New Meadows, Price Valley Guard Station, Tamarack, and Lost Valley
Reservoir around 300 PM MDT.
Black Lake around 310 PM MDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
A Severe Thunderstorm Watch remains in effect until 900 PM MDT/800 PM
PDT/ for southwestern Idaho...and northeastern Oregon.
&&
LAT...LON 4513 11628 4511 11630 4511 11615 4516 11612
4515 11612 4476 11607 4462 11641 4507 11705
4508 11679 4515 11672 4527 11669 4527 11635
TIME...MOT...LOC 2058Z 141DEG 55KT 4497 11638
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH
SAThe Boise radar (KCBX), 57 km away, was scanning. The volume nearest the first event began at 21:31 UTC.
6 thunderstorm wind, 1 hail. Local standard time, as filed.
A 61 mph wind gust was measured at the Mountain Home Airforce Base, associated with thunderstorm outflow.
Public reported inch size hail via social media.
Mesonet station CP2T11 measured a 72 mph wind gust associated with thunderstorm outflow.
Numerous reports of trees downed or large branches snapped throughout the Boise metropolitan area. The two points were based on two reports that reasonably capture the south to north extent of damage, with timing estimated by radar. Reports of storm damage extend as far west as Caldwell and as far east as Boise. With the extent of damage, and measured gusts nearby, this damage was likely caused by winds of at least 60 mph. This damage was caused by the same outflow boundary associated with thunderstorms.
Idaho Transportation Department Mesonet ITD03 measured a 59 mph wind gust associated with thunderstorm outflow.
A 68 mph wind gust was recorded at the Boise Airport, associated with thunderstorm outflow.
Idaho Transportation Department Mesonet CN2T6 measured a 59 mph wind gust associated with thunderstorm outflow.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2026Every state in 2026This day in weather historyWarnings in Idaho, May 2026
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: 1328485, 1328491, 1328486, 1328490, 1328488, 1328487, 1328489.