High pressure over the Southwest allowed monsoonal moisture to re-enter the region on this day, resulting in several intense heavy rain and hail-producing storms over the mountains and deserts. Dry air aloft along the western edge of the high contributed to the severe potential for hail.
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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.
High pressure over the Southwest allowed monsoonal moisture to re-enter the region on this day, resulting in several intense heavy rain and hail-producing storms over the mountains and deserts. Dry air aloft along the western edge of the high contributed to the severe potential for hail. A spotter in Lucerne Valley reported nickel-sized hail, on the north side of the San Bernardino County mountains. Flash flooding and debris flows of 1 to 2 feet from the Banner Fire scar closed Highway 78 east of Julian in the Banner Grade.
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 12, 8:30 AM PST, 4 hours earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN DIEGO CA 930 AM PDT TUE AUG 12 2014 .SYNOPSIS... ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVER THE MOUNTAINS AND DESERTS THROUGH THIS EVENING. HOWEVER...AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL MOVE INLAND OVER CALIFORNIA TONIGHT AND WEDNESDAY...BRINGING DRIER AND SLIGHTLY COOLER CONDITIONS TO THE REGION. SOUTHWESTERLY FLOW ALOFT WILL PREVAIL ACROSS THE REGION THROUGH EARLY NEXT WEEK...WITH DRY CONDITIONS PREVAILING. TEMPERATURES WILL REMAIN NEAR OR SLIGHTLY BELOW NORMAL MOST AREAS DURING THE WEEK...WITH COASTAL LOW CLOUDS AND FOG POSSIBLE ALONG THE COAST EACH NIGHT. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... WATER VAPOR IMAGERY SHOWS A TROUGH OF LOW PRESSURE DIGGING ALONG THE WEST COAST THIS MORNING...WITH AN IMPRESSIVE NEGATIVELY TILTED DISTURBANCE LIFTING ACROSS NORTHERN CALIFORNIA AND NEVADA AT THIS TIME. MEANWHILE...THE REMNANTS OF AN MCS AND OUTFLOW BOUNDARY MOVED ACROSS SOUTHEASTERN CALIFORNIA THIS MORNING...WHICH BROUGHT SOME SCATTERED SHOWERS AND THUNDERSTORMS TO OUR SOUTHERN MOUNTAINS AND DESERTS. A COUPLE OF LOCATIONS IN THE SAN DIEGO COUNTY MOUNTAINS PICKED UP A FEW HUNDREDTHS...WHILE DESERT LOCATIONS ONLY REPORTED TRACE AMOUNTS. ALTHOUGH THINGS ARE NOW RELATIVELY QUIET...EXPECT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TO REDEVELOP OVER THE MOUNTAINS AND DESERTS AGAIN THIS AFTERNOON. THE 12Z KNKX SOUNDING SHOWS PW VALUES OF 1.52 INCHES...WHICH MEANS FLASH FLOODING COULD BE POSSIBLE. HOWEVER...THE UPPER LEVEL WINDS ARE RANGING BETWEEN 15 AND 25 KT...SO ANY STORMS THAT FORM WILL LIKELY ONLY PRODUCE BRIEF SHOWERS OF ANY GIVEN AREA. AS THIS TROUGH OF LOW PRESSURE ALONG THE WEST COAST MOVES INLAND TONIGHT AND ON WEDNESDAY...DRIER CONDITIONS WILL DEVELOP ACROSS SOUTHERN CALIFORNIA. A MINOR COOLING TREND WILL ALSO DEVELOP...WITH THE MARINE LAYER WILL DEEPENING EVER SO SLIGHTLY AS WELL FOR WEDNESDAY. THE MODELS THEN SHOW SOUTHWESTERLY FLOW ALOFT PREVAILING ACROSS SOUTHERN CALIFORNIA THROUGH EARLY NEXT WEEK...AS ANOTHER TROUGH DEVELOPS ALONG THE COAST. THE HEIGHT OVER SOUTHERN CALIFORNIA MAY VERY A BIT FROM DAY TO DAY...BUT EXPECT TEMPERATURES TO REMAIN NEAR OR SLIGHTLY BELOW SEASONAL NORMS FOR THE PERIOD...WITH DRY CONDITIONS PREVAILING. && .AVIATION... 121530Z...LOW CLOUDS ARE CLEARING ALONG THE COASTS TO INLAND VALLEYS ABOUT AS FORECAST THIS MORNING WITH LOW CLOUDS DISSIPATING AND ONLY A FEW HIGH CLOUDS AFTER 121900Z. EXPECT A RETURN OF LOW CLOUDS WITH BASES NEAR 1500 FEET MSL AND TOPS NEAR 2200 FEET MSL AFTER 131000Z. THE MOUNTAINS AND DESERTS...EXPECT SCATTERED TO BROKEN CLOUDS AOA 10000 FEET MSL TODAY AND ISOLATED THUNDERSTORMS THIS AFTERNOON AFTER 122000Z WITH GUSTY AND ERRATIC WINDS NEAR STORMS. GREATEST RISK OF THUNDERSTORMS SHOULD BE OVER BY 130500Z. && .MARINE... 1000 AM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH SATURDAY. && .SKYWARN... SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS. && .SGX WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC...PALMER AVIATION/MARINE...PIERCE
The Edwards AFB radar (KEYX), 97 km away, was scanning. The volume nearest the first event began at 20:28 UTC.
1 hail, 1 debris flow. Local standard time, as filed.
A trained spotter reported nickel size hail and heavy rain along Highway 247 just east of Lucerne Valley near Camp Rock Road.
A debris flow was observed with 18 to 24 inches of mud being removed from Highway 78 by Caltrans. A culvert had overflowed onto road, directly below a recent wildfire scare on the Banner Grade. The road was closed east of Julian and clean up was ongoing on the following day.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2014Every state in 2014This day in weather historyWarnings in California, August 2014
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: 539357, 539356.