Tropical moisture pushed up into central California along the west side of a large high pressure center which was positioned over the four corners region on July 24 and July 25. As the atmosphere destabilized in the afternoon, thunderstorms developed over the higher elevations of the Southern Sierra Nevada each day.
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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 HNX wrote it up.
Tropical moisture pushed up into central California along the west side of a large high pressure center which was positioned over the four corners region on July 24 and July 25. As the atmosphere destabilized in the afternoon, thunderstorms developed over the higher elevations of the Southern Sierra Nevada each day. While the thunderstorms on the afternoon of the July 24 were localized for the most part, measurable precipitation was more widespread on the afternoon of July 25 when scattered thunderstorms developed over the mountains. Some of these thunderstorms drifted westward into the Sierra foothills and the San Joaquin Valley. A few of the thunderstorms in the Sierra Nevada produced very heavy rainfall and flash flooding was observed at Tuolumne Meadows in Yosemite National Park. While amounts at most locations were generally a tenth of an inch of inch of less, a few locations in the Central Sierra in Tuolumne and Madera Counties picked up over half an inch of rainfall in three hours or less.
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 Hanford, CA wrote its last area forecast discussion before the first event at Jul 25, 1:50 PM PST, 1 hour 10 minutes earlier.
Area Forecast Discussion National Weather Service Hanford CA 250 PM PDT Thu Jul 25 2019 .SYNOPSIS... A large area of high pressure will maintain widespread triple digit heat across the San Joaquin Valley, West Side Hills and Kern County Deserts through at least Monday. The peak of this heat should occur this weekend. Isolated afternoon and evening thunderstorms are possible through Friday in the Southern Sierra Nevada. && .DISCUSSION... Another round of afternoon thunderstorms already flaring-up as monsoonal moisture continues to surge north into the region. While the Sierra Nevada and Tehachapi Range will keep thunderstorm activity confined to the mountains and deserts, a few stray showers could reach the lower foothills before sunset this evening. Yet, with abundant moisture and smaller-scale disturbances moving into the area, thunderstorms are very likely outside of the San Joaquin Valley. Enough moisture, instability and lift could support brief heavy precipitation over the favored areas. This thinking lead to the issuance of a flash flood watch over the deserts and mountains through 11 PM PDT this evening. In the next few days, the trend will be to increase the heat as advisories and watches are currently in effect, and decrease the moisture. Therefore, while thunderstorms may still develop on Friday, the threat will slowly diminish during the weekend. In the storm term, model upper air analysis indicates that weak disturbances will attempt to ride over the ridge on Friday. Once this occurs, the flow aloft becomes more southwesterly and begins to lose the monsoonal flow component. Therefore, dry air will start to surge into the region from the west while the center of the high pressure area remains near the four corners. While the threat of convective activity will lessen, the heat will continue until a stronger onshore flow develops. Models show the high retrograding toward Southern California during the weekend. Placing the high over California will lead to more heat. This scenario warranted the issuance of an excessive heat watch as the potential for a heat warning exist around the Saturday/Sunday time frame. By Monday, longer range models solutions indicate the possible introduction of a stronger trof pattern entering the West Coast. While models do show some uncertainty in the possible solution, confidence remains high that a trof could enter the area at the start of the week. By Tuesday, models place the trof axis more ashore as the high pressure center moves more toward New Mexico/Northern Texas. This change in the pattern will lead toward a cooling trend that may finally break the 100 degree streak. Afterward, the pattern shows little change as triple digit heat may not return to the area until after the start of the new month. && .AVIATION... Areas of MVFR and local mountain obscuring IFR over the Southern Sierra Nevada from scattered showers and isolated thunderstorms. Otherwise, VFR conditions will prevail across the central CA interior for at least the next 24 hours. && .AIR QUALITY ISSUES... On Thursday July 25 2019... Unhealthy for sensitive groups in Fresno, Kern and Tulare Counties and Sequoia National Park and Forest. Further information is available at Valleyair.org && .CERTAINTY... The level of certainty for days 1 and 2 is high. The level of certainty for days 3 through 7 is medium. Certainty levels include low...medium...and high. Please visit www.weather.gov/hnx/certainty.html for additional information an/or to provide feedback. && .HNX WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch until 11 PM PDT this evening for CAZ192>199. Heat Advisory until 8 PM PDT Friday for CAZ179>189. Excessive Heat Watch from Saturday morning through Sunday evening for CAZ179>189. && public/aviation....Molina weather.gov/hanford
The San Joaquin Valley radar (KHNX), 176 km away, was scanning. The volume nearest the first event began at 23:01 UTC.
1 flash flood. Local standard time, as filed.
Yosemite Park Rangers reported flash flooding near the Dana Creek and State Route 120 intersection at Tuolumne Meadows where 40 people were rescued when the river swelled and separated them from the highway.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2019Every state in 2019This day in weather historyWarnings in California, July 2019
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: 832053.