An upper level ridge brought a cold front to the region that allowed for severe thunderstorms to form near Ontario, OR-Emmett, ID and brought blowing dust that impeded visibility in Caldwell, ID.
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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.
An upper level ridge brought a cold front to the region that allowed for severe thunderstorms to form near Ontario, OR-Emmett, ID and brought blowing dust that impeded visibility in Caldwell, ID.
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 Apr 29, 1:46 PM MST, 1 hour 14 minutes earlier.
Area Forecast Discussion National Weather Service Boise ID 246 PM MDT Mon Apr 29 2024 .SHORT TERM...Tonight through Wednesday night...An unseasonably cool upper level trough is moving across the Pacific NW today. This system is bringing a cold front through the area, and has reached Ontario, OR as of 2pm MDT. This front will continue to track southeast through the afternoon, and temperatures will slowly fall behind the front, with rain, snow and graupel showers mainly north of a line from Burns OR to Boise ID. Isolated thunderstorms possible too. The front is forecast to generate windy conditions in the upper Treasure and Magic Valleys and Camas Prairie through this evening where a wind advisory remains in effect. The upper level trough will remain over the area on Tuesday, keeping temperatures around 10 to 15 degrees below normal. The coldest air aloft will reach -30C at 500mb and extend from a line north of Burns to Boise on Tuesday. Slightly warmer 500mb temperatures near the NV border will lessen the chance of showers. Scattered showers will redevelop on Tuesday afternoon with a slight chance of thunderstorms, where the coldest air aloft is. Another shortwave moves south into the upper level trough on Wednesday morning, enhancing the threat of snow showers over the area. 500mb temperatures reach -33C on Wednesday morning, which is near record cold for this time of year. Light snow possible down to the valley floors, but precipitation will be showery in nature, so some places may see snow, while others will not. Snow showers will linger over the mountains on Wednesday afternoon, but warmer air aloft and ridging will bring drier and more stable conditions by Wednesday evening. .LONG TERM...Thursday through Monday...Long-term models are showing poor agreement that gets worse with time. As a result, most aspects of the forecast have a high degree of uncertainty. A compact low will move in from the northwest on Thursday, bringing precipitation through Thursday night with breezy afternoon winds. Chance of precip is fairly low, 25-35% in higher terrain and ~10% in lower valleys. Most precipitation will be rain, but above 5000 ft MSL snow becomes possible since some colder air lingers from the low earlier in the week. Instability in central Oregon will support a slight chance of thunderstorms. The track of this low varies a little model to model, but most of the disagreement is in the coverage of the precipitation, hence the mediocre precipitation chances. A brief calm period persists Friday into Saturday morning thanks to a ridge of high pressure. At the same time, a deep closed low from the Gulf of Alaska tracks southeast along the Canadian west coast. While models are beginning to show more agreement with each run, they are still not quite there. The GFS continues to the low making landfall in California, and then putting us under a deformation zone as it moves east. While the 12z EC now shows the core of the low moving directly overhead, putting us under the coldest part of the airmass. This is a fairly big change from the 06z EC, that showed the low becoming a longwave trough leading to still unsettled but a notably weaker weather pattern. The National Blend consensus is area- wide 30-50% precip chances beginning Saturday afternoon, dropping to 20-40% Sunday afternoon through the rest of the long-term. Saturday onwards each afternoon will have a chance of thunderstorms and breeziness. The spread in maximum temperature forecast is 10-20 degrees each day, with the consensus being normal temps. && .AVIATION...VFR. Widespread rain/snow showers in the north and isolated to scattered elsewhere. Instances of graupel and lightning are possible in the north as the chance of thunderstorms is just below 30%. Mountains obscured. Snow levels 4000-5000 ft MSL, lowering to 2500-3500 ft MSL by Tue/06Z. Surface winds: W 15-25 kt with gusts to 30 kt this afternoon, peak gusts of up to 40 kt. Winds aloft at 10kft MSL: W 20-30 kt. KBOI...VFR with increasing clouds. Slight chance (less than 20 percent) of -SHRA between Mon/18Z and Tue/00Z. Surface winds: NW 12- 15 kt increasing to 15-20 kt with gusts to 23-28 kt this afternoon. Winds decrease to 8-12 kt around Tue/05z and switch to SE around Tue/11z. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Wind Advisory until 7 PM MDT this evening IDZ014-016-028. OR...None. && www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise SHORT TERM...KA LONG TERM....JM AVIATION.....JM
Special Weather Statement
National Weather Service Boise ID
329 PM MDT Mon Apr 29 2024
IDZ012-014-ORZ064-292215-
Upper Treasure Valley ID-Lower Treasure Valley ID-
Oregon Lower Treasure Valley OR-
329 PM MDT Mon Apr 29 2024
...GUSTY WINDS WILL IMPACT NORTHWESTERN ADA...WESTERN PAYETTE...
NORTHERN CANYON...SOUTHWESTERN GEM AND NORTHEASTERN MALHEUR COUNTIES
THROUGH 415 PM MDT...
At 327 PM MDT, Doppler radar was tracking an area of blowing dust
driven by winds 50-55 mph, moving southeast into the Lower
Treasure Valley of Idaho, at 35 mph.
HAZARD...Wind gusts of 50 to 55 mph.
SOURCE...Observation.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4385 11709 4409 11683 4379 11629 4351 11656
TIME...MOT...LOC 2127Z 310DEG 29KT 4392 11688
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH
SPThe national radar mosaic for the moment the first event began.
1 dust storm, 1 high wind. Local standard time, as filed.
A member of the public reported that visibility went down to less than a quarter mile due to the outflow winds from a thunderstorm.
A member of the public measured a wind gust of 62 mph from a thunderstorm outflow boundary.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2024Every state in 2024This day in weather historyWarnings in Idaho, April 2024
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: 1173811, 1173812.