Enough monsoonal moisture made its way into the mountains and deserts to set off a few isolated thunderstorms, mainly in southwestern San Bernardino County. A spotter reported an area of water around 6 inches deep and about 50 feet wide flowing down Buena Vista Road near Lucerne Valley.
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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 SGX wrote it up.
Enough monsoonal moisture made its way into the mountains and deserts to set off a few isolated thunderstorms, mainly in southwestern San Bernardino County. A spotter reported an area of water around 6 inches deep and about 50 feet wide flowing down Buena Vista Road near Lucerne Valley. There was also dirt and rocks on the roads, including Highway 18 and Custer Road, with a total rainfall of 1.5 inches reported. Another spotter measured one inch of rain in ten minutes elsewhere in Lucerne Valley. A flash flood warning was in effect for these areas.
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 4, 12:08 PM PST, 52 minutes earlier.
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
108 PM PDT THU AUG 4 2016
.SYNOPSIS...
Lingering monsoonal moisture could bring a few showers and thunderstorms
over the mountains and deserts this afternoon. Drier air moves in
for Friday and continues through the middle of next week as an
upper level trough moves in from the west. This trough will result
in slightly lower temps along with night and morning low clouds
pushing well into the inland valleys.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
This afternoon...a few showers/tstms have developed over the San
Bernardino mtns and will likely continue for the next several
hours. At least until the trough moving in from the northwest
depletes the moisture or the daytime heating is lost...whichever
comes first. The marine layer low clouds have been pushed 20-30
miles offshore but will likely return this evening, spreading
inland to the foothills by early Fri morning. Temperatures are
mostly a few degrees lower than this time yesterday and will
likely continue to trend slowly down over the next several days.
The upper high over the 4 corners continues to weaken and shift to
the east as the trough of low pressure deepens over the west
coast and moves inland. By this evening, we expect the flow aloft
to become uniformly westerly, accelerating the drying trend.
For Fri through the middle of next week...Broad troughing over the
western U.S. will dominate our weather. It will keep conditions
fair with the monsoonal moisture well to the east. Temperatures
will be near to several degrees below seasonal averages with a
deep marine layer for more extensive low clouds during the nights
and mornings.
&&
.AVIATION...
0419450Z...Coast/Valleys...Low clouds with bases around 1800 ft MSL
and tops around 2500 feet MSL out over the coastal waters will move
into the coastal areas after 05/00Z and continue to around 25-35 miles
inland overnight. Bases will again be near 1800 feet MSL. Risk of low
clouds becoming more solid and deeper this evening compared to this
morning is moderate, so will plan on low clouds into KONT tonight. Also
confidence in the timing of the low clouds moving in this evening at
KSAN in the TAF is also moderate.
Mtns/Deserts...Isolated SHRA/TSRA possible through 05/02Z this
afternoon, mainly over the mountains and high deserts. CB bases will
be around 10000 ft MSL with tops to near 30000 ft MSL. Thunderstorms
could produce small hail, strong downdraft winds and reduced
visibility. Otherwise, unrestricted vis and SCT clouds AOA 10000 ft
through Friday morning.
&&
.MARINE...
No hazardous marine weather is expected through Monday.
&&
.BEACHES...
A 3 foot/17-20 sec south swell from 200 degrees will create strong
rip and longshore currents, and elevated surf of 3-5 feet along
south-southwest facing beaches through this afternoon. A Beach Hazard
Statement remains in effect through this afternoon.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX Watches/Warnings/Advisories...
CA...Beach Hazards Statement until 5 PM PDT this afternoon for Orange
County Coastal Areas-San Diego County Coastal Areas.
PZ...None.
&&
PUBLIC...PG
AVIATION/MARINE/BEACHES...SmallThe Santa Ana Mts radar (KSOX), 87 km away, was scanning. The volume nearest the first event began at 20:58 UTC.
1 flash flood. Local standard time, as filed.
A spotter reported 6 inches of water about 50 feet wide flowing down Buena Vista Road with dirt and rock on the roads, including Highway 18 and Custer Road. Total rain of 1.5 inches reported. Another spotter reported 1 inch of rain in ten minutes nearby.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2016Every state in 2016This day in weather historyWarnings in California, August 2016
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: 656741.