Moist southwest flow coupled with afternoon instability set off severe thunderstorms with large hail and strong winds across parts of Southwest Idaho.
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.
Moist southwest flow coupled with afternoon instability set off severe thunderstorms with large hail and strong winds across parts of Southwest Idaho.
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 Aug 24, 1:44 PM MST, 11 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BOISE ID 244 PM MDT SAT AUG 24 2013 .SHORT TERM...SMOKE FROM THE RIM FIRE IN EASTERN CALIF HAS OVERSPREAD MOST OF OUR CWA BUT HAS HAD LITTLE EFFECT ON TEMPS WHICH ARE GETTING QUITE WARM TODAY. PERSISTENT SOUTHWEST WINDS ALOFT WILL CONTINUE TO IMPORT SMOKE TO OUR CWA FOR AT LEAST THE NEXT SEVERAL DAYS IF THE FIRE CONTINUES AS IT IS NOW. MEANWHILE...AS OF 2 PM MDT MONSOON MOISTURE OVER OUR EASTERN ZONES IN IDAHO HAS ALREADY BEGUN TO DEVELOP SHOWERS AND THUNDERSTORMS WITH A COUPLE STRONG CELLS CONTAINING HEAVY RAIN AND GUSTY WINDS. THUNDERSTORMS WILL CONTINUE THERE THROUGH THIS EVENING. SLIGHT CHANCE OF THUNDERSTORMS THERE AGAIN SUNDAY AFTERNOON AND EVENING. MOISTURE IN CENTRAL OREGON ASSOCIATED WITH PACIFIC UPPER TROUGH JUST OFF THE COAST WILL CONTINUE ISOLATED THUNDERSTORMS IN THE BLUE MOUNTAINS OF WESTERN BAKER COUNTY THIS EVENING...AND AGAIN SUNDAY AFTERNOON AND EVENING. LITTLE CHANGE IN TEMPERATURES THE NEXT TWO DAYS. .LONG TERM...MONDAY NIGHT THROUGH SATURDAY...OUR CWA REMAINS BETWEEN THE OFFSHORE UPPER LEVEL TROUGH AND THE UPPER LEVEL RIDGE OVER THE CENTRAL GREAT PLAINS. MODELS AGREE ON SLOW RETROGRESSION OF THE RIDGE TUESDAY THROUGH THURSDAY AS ITS CENTER MIGRATES FROM KANSAS TO THE SOUTHERN ROCKIES. FOR US THIS IMPLIES GRADUAL WARMING WITH BOTH MAX AND MIN TEMPERATURES AVERAGING 5 TO 8 DEGREES ABOVE NORMAL. WITH CONTINUING SOUTHWEST FLOW ALOFT AND A SOURCE OF MONSOON MOISTURE OVER THE SOUTHWEST U.S....THUNDERSTORMS WILL BE POSSIBLE EACH DAY AS MOIST UNSTABLE AIR IS ADVECTED NORTH. TRAJECTORY FORECASTS SHOW US STAYING ON THE WESTERN EDGE OF THIS MOISTURE. SO WE ARE CONFINING THUNDERSTORMS TO OUR EASTERN ZONES...FROM SOUTHERN TWIN FALLS COUNTY NORTH INTO THE CENTRAL IDAHO MOUNTAINS. FRIDAY AND SATURDAY MODEL AGREEMENT AND CONFIDENCE DETERIORATE. THE OPERATIONAL ECMWF WANTS TO BRING THE TROUGH INLAND OVER IDAHO ON SATURDAY...WHEREAS THE GFS KEEPS IT OVER THE COAST. ENSEMBLE MEANS OF BOTH MODELS ARE MORE IN LINE WITH THE OPERATIONAL GFS...BUT THEY DO WEAKEN THE RIDGE OVER THE NORTHWEST STATES. SO WE ARE LOWERING TEMPERATURES JUST A FEW DEGREES...MIDWAY BETWEEN MODEL GUIDANCE EXTREMES. && .AVIATION...LOCAL MVFR/IFR SMOKE WILL CONTINUE FROM THE CENTRAL IDAHO MOUNTAINS TO THE NEVADA BORDER. SMOKE LAYERS AOA 10 KFT WILL PERSIST THROUGH THE WEEKEND. EXPECT ISOLATED TO SCATTERED THUNDERSTORMS THIS EVENING...AND AGAIN SUNDAY AFTERNOON AND EVENING...FROM THE WESTERN MAGIC VALLEY TO THE NEVADA BORDER...OVER THE CENTRAL IDAHO MOUNTAINS...AND NORTHWEST OF A LINE FROM KLKV TO KMYL. SURFACE WINDS...MAINLY SOUTH 5-15 KTS. GUSTS TO 30 KTS NEAR THUNDERSTORMS. WINDS ALOFT...SOUTHWEST TO 20 KTS THROUGH 10K FEET MSL. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...NONE. OR...NONE. && WEATHER.GOV/BOISE SHORT TERM...LC LONG TERM....JT/WH AVIATION.....JT
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE BOISE ID 536 AM MDT SAT AUG 24 2013 IDZ011>016-028>030-033-ORZ061>064-251145- WEST CENTRAL MOUNTAINS-LOWER TREASURE VALLEY ID-BOISE MOUNTAINS- UPPER TREASURE VALLEY-SOUTHWEST HIGHLANDS-WESTERN MAGIC VALLEY- CAMAS PRAIRIE-OWYHEE MOUNTAINS-SOUTHERN TWIN FALLS COUNTY- UPPER WEISER RIVER-HARNEY COUNTY-BAKER COUNTY-MALHEUR COUNTY- LOWER TREASURE VALLEY OR- 536 AM MDT SAT AUG 24 2013 /436 AM PDT SAT AUG 24 2013/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL IDAHO...SOUTHWEST IDAHO...WEST CENTRAL IDAHO...NORTHEAST OREGON AND SOUTHEAST OREGON. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED.
The Boise radar (KCBX), 148 km away, was scanning. The volume nearest the first event began at 20:56 UTC.
3 hail. Local standard time, as filed.
Local media reported penny to nickel sized hail around the Wendell, Idaho area.
Local media reported quarter sized hail around the Jerome, Idaho area.
Local media reported Quarter sized hail aound the Glenns Ferry area.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2013Every state in 2013This day in weather historyWarnings in Idaho, August 2013
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: 473982, 473983, 474020.