Several reports of strong wind gusts, funnel clouds and large hail occurred.
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 PIH wrote it up.
Several reports of strong wind gusts, funnel clouds and large hail occurred.
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 Pocatello, ID wrote its last area forecast discussion before the first event at Sep 19, 12:45 PM MST, 1 hour 18 minutes earlier.
Area Forecast Discussion National Weather Service Pocatello ID 145 PM MDT Sat Sep 19 2020 .SHORT TERM...Rest of Tonight...Isolated Showers and thunderstorms have already developed over the Central Mountains this afternoon while the earlier line of showers from this morning exits into western Wyoming. Several short term models show a developing line of showers/thunderstorms during the mid- afternoon hours across the Arco Desert/Upper Snake River Plain tracking southeastward across the I-15 corridor and Idaho Falls to Rexburg. Within the organized line would be the potential for small hail and gusty winds while it continues it trek toward the Teton Valley early this evening. Out ahead of this line, isolated thunderstorms are possible this afternoon as well, including the southern highland areas all the way to eastward to Bear Lake. Eastern Magic Valley area and South Hills areas area least likely to see thunderstorm develop but are expected to see gusty west or northwest winds. Improvement to wind speeds and decreasing chances of thunderstorms are forecast between 8 pm and 10 pm. .Sunday through Tuesday...Zonal flow will allow for mild temperatures and generally light winds this forecast period. A ridge of high pressure begins to build back into the area from the south by Monday, which will shift our winds back from the southwest and begin to increase temperatures slightly. This time period is expected to be precipitation free. ND LONG TERM...Tuesday through Saturday. A weak system will pass east south of Idaho but expect a chance of showers and thunderstorms in the far eastern part of the state near the Wyoming border. Will be dry Wednesday and Thursday with the chance of showers returning mainly to the central mountains and eastern highlands. Temperatures will be above normal through Friday with cooling expected by Saturday as the next system works east. Low confidence at the end of the long term period as models greatly different with GFS slower and wetter and European model drier and weaker with the end of the week system. Winds may increase by Friday into Saturday as well. GK && .FIRE WEATHER... Isolated to widely scattered thunderstorms will be possible through sunset tonight with some breezy conditions as well. Gusts of 20 to 30 mph will be possible especially in zones 410. Brunt of thunderstorm activity will be in zones 475, 476, 422, 410 and 411. All locations will see at least isolated activity. Humidity is way up today and should remain so through Sunday. Temperatures will begin to moderate Sunday and remain above normal through next week. Next chance for showers will be in the far east Tuesday mainly zones 413, 410 and 411. Could be breezy as well Tuesday but not expecting highlights as humidity stays above 15 percent. GK && .AVIATION...Showers and thunderstorms have developed this afternoon and have vicinity at all sites with SUN, BYi and DIJ most likely to see on station but can't rule out anywhere. Will have 10 to 20 knot sustained winds through sunset at all sites before dying down. Will have clear skies throughout the day Sunday with up valley 10 to 15 knot afternoon winds at PIH and IDA. GK && .AIR STAGNATION...Air Quality concerns from regional wildfire smoke look to improve today as a low pressure trough moves through our area and flow turns more westerly. This essentially 'closes off' flow from the CA wildfires for the time being. Keep in mind though that smoke from local wildfires will certainly still impact the air quality. This pattern of a general westerly flow looks to continue through Monday before gradually opening back up again from the southwest. ND && .PIH WATCHES/WARNINGS/ADVISORIES... None. &&
Special Weather Statement
National Weather Service Pocatello ID
154 PM MDT Sat Sep 19 2020
IDZ052-068-070-072>075-192045-
Challis/Pahsimeroi Valleys ID-Arco/Mud Lake Desert ID-
Sawtooth/Stanley Basin ID-Wood River Foothills ID-
Sun Valley Region ID-Big Lost Highlands/Copper Basin ID-
Lost River Valleys ID-
154 PM MDT Sat Sep 19 2020
...Showers and thunderstorms continue to develop this afternoon
with small hail observed...
At 151 PM MDT, trained weather spotters reported small hail within a
thunderstorm south of Ketchum. These thunderstorms will continue to
be capable of producing half inch hail and winds in excess of 30 mph
as they track to the northeast around 20 mph. Additional
thunderstorm development is expected this afternoon.
Locations impacted include...
Hailey, Ketchum, Sun Valley, Little Wood Reservoir, Bellevue, Herd
Lake, Garfield Ranger Station, Copper Basin Airport and Twin Bridges
Airport.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional
information and possible warnings from the National Weather Service.
Persons in campgrounds should consider seeking sturdy shelter until
these storms pass.
&&
LAT...LON 4419 11399 4344 11357 4339 11453 4340 11455
4343 11455 4347 11451 4349 11451 4350 11456
4353 11460 4356 11459 4357 11463 4359 11465
4359 11468 4366 11466 4369 11469 4374 11467
4375 11469 4380 11470 4381 11471 4381 11473
TIME...MOT...LOC 1951Z 240DEG 48KT 4366 11415
NDSpecial Weather Statement National Weather Service Pocatello ID 230 PM MDT Sat Sep 19 2020 IDZ057>059-192115- Franklin/Eastern Oneida Region ID-Marsh and Arbon Highlands ID- Raft River Region ID- 230 PM MDT Sat Sep 19 2020 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN ONEIDA AND SOUTHEASTERN POWER COUNTIES UNTIL 315 PM MDT... At 229 PM MDT, Doppler radar was tracking isolated thunderstorms 13 miles northwest of Holbrook Summit, or 22 miles north of Snowville, moving east at 20 mph. Nickel size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Holbrook, Arbon, Daniels Reservoir and Roy. LAT...LON 4209 11289 4234 11299 4251 11248 4225 11237 TIME...MOT...LOC 2029Z 251DEG 19KT 4228 11286 ND
Special Weather Statement
National Weather Service Pocatello ID
241 PM MDT Sat Sep 19 2020
IDZ052-067>069-074-192145-
Arco/Mud Lake Desert ID-Lost River Range ID-
Beaverhead/Lemhi Highlands ID-Big Lost Highlands/Copper Basin ID-
Lost River Valleys ID-
241 PM MDT Sat Sep 19 2020
...SCATTERED THUNDERSTORMS NOW TRACKING ACROSS SOUTHEASTERN
CUSTER...CENTRAL BUTTE AND SOUTHWESTERN CLARK COUNTIES UNTIL 345 PM
MDT...
At 239 PM MDT, Doppler radar was tracking scattered thunderstorms
near Darlington, or 13 miles north of Arco, moving east at 20 mph.
Half inch hail and winds in excess of 40 mph will be possible with
these storms.
Locations impacted include...
Arco, Mackay, Grouse, Mackay Reservoir, Darlington, Moore, Clyde and
Howe.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional
information and possible warnings from the National Weather Service.
Persons in campgrounds should consider seeking sturdy shelter until
storms have passed.
&&
LAT...LON 4383 11279 4350 11360 4398 11387 4423 11328
4423 11298
TIME...MOT...LOC 2039Z 251DEG 19KT 4382 11335
NDSpecial Weather Statement National Weather Service Pocatello ID 247 PM MDT Sat Sep 19 2020 IDZ057-192130- Raft River Region ID- 247 PM MDT Sat Sep 19 2020 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN ONEIDA AND SOUTHEASTERN CASSIA COUNTIES UNTIL 330 PM MDT... At 247 PM MDT, Doppler radar was tracking strong thunderstorms approximately 7 miles northwest of Juniper, or 20 miles northwest of Snowville, moving east at 20 mph. Nickel size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Juniper, Sweetzer Summit and Bridge. PRECAUTIONARY/PREPAREDNESS ACTIONS... This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. Persons in campgrounds should consider seeking sturdy shelter until this storm passes. && LAT...LON 4212 11341 4223 11294 4200 11285 4199 11339 TIME...MOT...LOC 2047Z 251DEG 19KT 4211 11306 ND
Special Weather Statement
National Weather Service Pocatello ID
256 PM MDT Sat Sep 19 2020
IDZ051-052-068-074-075-192145-
Arco/Mud Lake Desert ID-Shoshone/Lava Beds ID-
Wood River Foothills ID-Big Lost Highlands/Copper Basin ID-
Lost River Valleys ID-
256 PM MDT Sat Sep 19 2020
...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL BLAINE...SOUTHWESTERN
BUTTE AND NORTHEASTERN LINCOLN COUNTIES UNTIL 345 PM MDT...
At 255 PM MDT, Doppler radar was tracking a strong thunderstorm 10
miles east of Carey, moving east at 20 mph.
Winds in excess of 40 mph will be possible with this storm.
Locations impacted include...
Carey, Picabo, Craters Of The Moon and Shoshone Ice Caves.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
Conditions are favorable for funnel clouds across the affected area.
These funnel clouds are not expected to touch down, however if they
do touch down, winds are expected to be 50 mph or less. The National
Weather Service in Pocatello is monitoring the system closely.
&&
LAT...LON 4359 11335 4332 11318 4307 11430 4323 11438
4326 11437 4326 11439 4327 11440 4329 11440
TIME...MOT...LOC 2055Z 251DEG 19KT 4333 11374
NDPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE POCATELLO ID
258 PM MDT SAT SEP 19 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0224 PM HAIL 3 NNW MOORE 43.78N 113.38W
09/19/2020 E0.50 INCH BUTTE ID TRAINED SPOTTER
PEA TO MARBLE SIZED HAIL. LOTS OF LIGHTNING. MODERATE
RAIN.
0224 PM HAIL 2 NNW MOORE 43.77N 113.38W
09/19/2020 E0.88 INCH BUTTE ID TRAINED SPOTTER
STRONG WIND GUSTS EST 40 MPH. LOTS OF LIGHTNING.
0233 PM HAIL 1 SE DARLINGTON 43.81N 113.41W
09/19/2020 E0.50 INCH BUTTE ID TRAINED SPOTTER
MODERATE RAIN AND LOTS OF LIGHTNING.
&&
MHThe Salt Lake City radar (KMTX), 104 km away, was scanning. The volume nearest the first event began at 21:01 UTC.
5 thunderstorm wind, 3 funnel cloud, 1 hail. Local standard time, as filed.
A 63 mph wind gust recorded at the Moburg Canyon RAWS.
A 66 mph wind gust measured at Kettle Butte mesonet site on US Highway 20.
Funnel cloud photographed west of Ammon.
Roberts ARL site recorded 57 mph wind gust.
Well defined funnel cloud photographed 8 miles west of Idaho Falls by KIDK viewer.
One inch hail caused damage to roof in Idaho Falls with holes the size of a quarter.
KPVI viewer shared photograph of funnel cloud north of Idaho Falls.
Fence damage in Ammon from thunderstorm winds.
The emergency manager reported downed trees and power lines in Parker.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2020Every state in 2020This day in weather historyWarnings in Idaho, September 2020
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: 922835, 922836, 922837, 922838, 922839, 922840, 922841, 922844, 922847.