A monsoon surge occurred on Sunday August 11, 2024. Numerous strong to severe thunderstorms erupted across the San Diego mountains and into the Riverside County mountains.
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 SGX wrote it up.
A monsoon surge occurred on Sunday August 11, 2024. Numerous strong to severe thunderstorms erupted across the San Diego mountains and into the Riverside County mountains. Thunderstorms produced hail, wind gusts and rainfall rates of 1 inch in 60 minutes.
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 San Diego, CA wrote its last area forecast discussion before the first event at Aug 11, 8:35 AM PST, 3 hours 25 minutes earlier.
Area Forecast Discussion National Weather Service San Diego CA 935 AM PDT Sun Aug 11 2024 .SYNOPSIS... Slightly cooler today with continued chances of thunderstorms over the mountains and deserts. Lower thunderstorm chances on Monday with any activity limited to the mountains and southern deserts. Drier with near normal temperatures Tuesday through the end of the week. Patchy low clouds and fog will gradually increase for the coastal areas each night and morning. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Coastal low clouds never made their presence felt over land this morning, probably discouraged by the easterly flow aloft from our inverted trough aloft. This trough continues to bring in monsoonal moisture today and chances of thunderstorms for mountains and deserts. It looks quite unstable and humid, so we should get at least several decent storms this afternoon and early evening. Any storm would produce frequent lightning and could produce flash flooding and strong, gusty winds. Elsewhere it should be mostly sunny with a hampered marine layer. A coastal eddy today should help repair the marine layer, so coastal low clouds should make an earlier comeback late today and tonight. Temperatures will start to moderate today from those highs yesterday. The potential temp rise is literally dampened by the low level moisture intrusion this morning. So not so hot, but more muggy. The inverted trough overhead today will fade as a low pressure trough off the Pac northwest coast will amplify over the next couple days. This will effectively sweep away the monsoonal moisture, but enough residual moisture and instability remain over southeastern mountain/desert portions of our area for a slight chance of tstorms Monday afternoon. The amplifying trough to the north will help rebuild the marine layer and boost winds through mountain gaps into deserts during the afternoons and evenings. Temps will settle down to around normal. Coastal clouds will become more uniform, extensive and longer lasting, but still restrained to nights and mornings. Expect these seasonal and dry conditions to remain with very little day to day variation this entire week. && .AVIATION... 111530Z...Coast/Valleys...Mostly clear skies with some FEW-SCT clouds near 20K ft MSL. Low clouds based near 700-1100 ft MSL offshore with tops near 1200 FT MSL locally impacting coastal areas with local VIS 3-5 miles. ISO TSRA drifting into foothills and adjacent valleys west of the mountains this afternoon with the highest chance in SD County. Low cloud coverage confidence higher (50-70%) in cigs reaching coastal TAF sites later tonight, mainly after 06Z Mon based near 1000 ft MSL with tops to near 1500 ft MSL. Mountains/Deserts...SCT-BKN clouds with bases around 10,000 ft MSL develop after 16Z, followed by scattered TSRA between 19Z Sunday and 03Z Monday. Gusty and erratic winds possible near storms as well as MOD UDDFS. && .MARINE... No hazardous marine conditions are expected through Wednesday. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && PUBLIC...MM AVIATION/MARINE...Small
Preliminary Local Storm Report
National Weather Service San Diego CA
1214 PM PDT Sun Aug 11 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1210 PM Hail 5 W Pine Valley 32.83N 116.61W
08/11/2024 M0.50 Inch San Diego CA Trained Spotter
Weather spotter reported slightly larger
than pea sized hail and heavy rain, no wind,
along I-8.
&&
AOTSpecial Weather Statement
National Weather Service San Diego CA
1236 PM PDT Sun Aug 11 2024
CAZ048-050-056-058-061-062-065-112015-
San Diego County Mountains CA-San Diego County Deserts CA-
Riverside County Mountains CA-San Gorgonio Pass Near Banning CA-
Coachella Valley CA-San Bernardino and Riverside County Valleys-
The Inland Empire CA-San Diego County Inland Valleys CA-
1236 PM PDT Sun Aug 11 2024
...STRONG THUNDERSTORMS WILL IMPACT RIVERSIDE AND NORTH CENTRAL SAN
DIEGO COUNTIES THROUGH 115 PM PDT...
At 1233 PM PDT, NWS doppler radar was tracking a cluster of strong
thunderstorms over Warner Springs, or 15 miles south of Anza
northward to near Idyllwild in the Riverside County mountains. These
storms were nearly stationary. Thunderstorms will continue to develop
through 3 pm and isolated storms will havey heavy rainfall.
HAZARD...Wind gusts up to 40 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Southeastern Palm Springs, Idyllwild-Pine Cove, Hwy 78 Between Banner
And S2, Anza, Julian, Mt San Jacinto State Park, Hwy 243 Between
Banning And Idyllwild, Cuyamaca Rancho State Park, Ranchita, Hwy 79
Between Oak Grove And Aguanga, Mountain Center, Hwy 79 Between Warner
Springs And Oak Grove, Hwy 79 Between Santa Ysabel And Warner
Springs, Lake Henshaw, Borrego Palm Canyon, Hwy 74 Between Anza And
Palm Desert, S7 - East Grade Rd, Warner Springs, Lake Cuyamaca, and
Hwy 79 Between Julian And Lake Cuyamaca.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 3294 11652 3330 11683 3390 11676 3353 11622
3340 11642
TIME...MOT...LOC 1933Z 077DEG 1KT 3333 11666
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH
TardySpecial Weather Statement
National Weather Service San Diego CA
1241 PM PDT Sun Aug 11 2024
CAZ050-058-062-112030-
San Diego County Mountains CA-San Diego County Deserts CA-
San Diego County Inland Valleys CA-
1241 PM PDT Sun Aug 11 2024
...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN SAN DIEGO COUNTY
THROUGH 130 PM PDT...
At 1239 PM PDT, NWS doppler radar detected a strong thunderstorm
south of I-8. Earlier trained weather spotters reported hail.
A new strong thunderstorm over Potrero, or 8 miles southwest of I-8
between Pine Valley and Boulevard and near Campo. This thunderstorm
was nearly stationary or drifting southwest.
HAZARD...Wind gusts up to 40 mph and pea size hail.
SOURCE...Trained weather spotters.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Alpine, Mount Laguna, I-8 Between Pine Valley And Boulevard, Pine
Valley, Lake Morena, Potrero, Campo, Descanso, Skye Valley, La Posta
Indian Reservation, Barrett Lake, Tecate, Japatul Valley, Guatay,
Campo Indian Reservation, Dulzura, and Jamul.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 3257 11673 3283 11670 3291 11636 3260 11638
TIME...MOT...LOC 1939Z 057DEG 2KT 3265 11658
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH
TardyThe national radar mosaic for the moment the first event began.
2 hail, 2 heavy rain, 2 thunderstorm wind, 2 debris flow, 2 flash flood. Local standard time, as filed.
Trained spotter and meteorologist reported half inch sized hail from thunderstorm along I-8 in Pine Valley near 3500 feet MSL.
Mountain Center recorded 0.81 inches in 1 hour from thunderstorm. GW0998.|Temperature fell from 86 to 65F.
Thunderstorm wind gusts at Hoskings Ranch SDGE weather station. Also 1.25 inches rainfall at VCNC1 station. Persistent thunderstorms for up to 2 inches.
Rainfall of 2.54 inches in about 2 hours was recorded at the Mason Valley mesonet along S2 highway in the San Diego Deserts. Radar estimates as high as 3.50 inches.
NWS storm survey on August 12 showed leaves and debris along SR 78 at the entrance of Julian. The town of Julian live camera recorded hail for about 30 minutes. Hail was observed at 0.25 to 0.50 inch diameter.
NWS storm survey found several low water crossings on S2 highway with mud and debris including along the shoulders with erosion. Required the San Diego County crews to moved and plow mud and debris on the highway. Survey was Monday August 12.
Debris flow, rocks and flooding reported from Sunrise Highway to Kitchen Creek. Thunderstorms persisted in this area.
Lucky Five SDGE weather station recorded a thunderstorm wind gust of 43 mph at 240 pm August 11, 2024.
Anza Borrego State Park reported, video taped and photographs flash flooding from Fish Creek and across Split Mountain Road. Runoff caused damage to paved road. NWS Kineros modeling predicted 4 to 5 feet water levels at the exit of Fish Creek canyons before Split mountain road on the San Diego County side.
San Diego department of Public Works reported mud flows and flash flooding on the Great Southern Overland Stage route S2 and Vallecito Wash crossings. 2.54 inches of rain was recorded. Public Works also provided photos of the flooding and NWS did a storm survey the next day.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2024Every state in 2024This day in weather historyWarnings in California, August 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: 1214390, 1214455, 1214453, 1214388, 1214391, 1214392, 1214419, 1214389, 1214421, 1214385.