From the 12th to the 20th of October, an upper low traversed the southwest in a large loop, passing over Southern California twice. This period saw scattered showers and isolated thunderstorms.
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.
From the 12th to the 20th of October, an upper low traversed the southwest in a large loop, passing over Southern California twice. This period saw scattered showers and isolated thunderstorms. The majority of activity stayed below severe limits, but a brief landspout was reported near Menifee on the 17th.
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 Oct 17, 12:30 PM PST, 1 hour 10 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
130 PM PDT SAT OCT 17 2015
.SYNOPSIS...
A LOW PRESSURE TROUGH ALONG THE WEST COAST AND MOIST ONSHORE FLOW
WILL CONTINUE WIDESPREAD NIGHT AND MORNING LOW CLOUDS...FOG...AND
PATCHY DRIZZLE WEST OF THE MOUNTAINS...AND A CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE MOUNTAINS AND DESERTS THROUGH TUESDAY. LOW
PRESSURE IS FORECAST TO DEVELOP OVER THE LOWER COLORADO RIVER VALLEY
BY THE MIDDLE OF NEXT WEEK. THIS SHOULD RESULT IN DRYING...AND
WARMER WEATHER INTO NEXT WEEKEND.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
AFTER PARTIAL CLEARING THIS MORNING...LOW CLOUDS RAPIDLY REDEVELOPED
WEST OF THE MTS TODAY. THE LOW CLOUDS WERE WIDESPREAD ACROSS SAN
DIEGO AND ORANGE COUNTIES AT MIDDAY...WHILE THE INLAND EMPIRE WAS
MOSTLY CLEAR. CLOUDS WERE ALSO THICK OVER THE MTN CRESTS AND
OFFSHORE. ISOLATED RADAR ECHOES HAD POPPED BY 1 PM ON THE MTN SLOPES
AND FURTHER DEVELOPMENT IS LIKELY THROUGH EARLY EVENING. SURFACE
PRESSURE GRADIENTS WERE 3 MBS OR LESS TO/FROM THE DESERTS. WINDS
WERE GENERALLY LIGHT.
LATEST HRRR MODEL STILL SHOWS CONSIDERABLE SHWR/TSTM DEVELOPMENT
THIS AFTERNOON ALONG AND JUST WEST OF THE MTS. WITH HIGH SFC
DEWPOINTS IN PLACE AND PW WELL OVER ONE INCH IN MANY AREAS...EXPECT
TO SEE SOME DEVELOPMENT INTO THE EARLY EVENING. AFTER SUNSET...
DEEP MOISTURE IN PLACE SHOULD RESULT IN WIDESPREAD LOW CLOUDS
WITH PATCHY DRIZZLE AND FOG INLAND TO THE COASTAL SLOPES. A FEW
SHOWERS AND ISOLATED THUNDERSTORMS WILL STILL BE POSSIBLE...MAINLY
NEAR THE MTS. LOCALLY HEAVY RAIN IS POSSIBLE. SIMILAR WEATHER IS
EXPECTED ON SUN/MON.
WATER VAPOR IMAGERY SHOWED A STRONG CIRCULATION OFF THE NOCAL COAST
THIS MORNING. THIS SYSTEM WILL DIG SOUTH THROUGH TUE...AND MAY CUT
OFF OVER THE LOWER COLORADO RIVER VALLEY FOR A TIME MIDWEEK. SOME
WRAP AROUND MOISTURE CONTINUES A THREAT OF SHWRS IN THE MTS/DESERTS
THROUGH WED AFTERNOON...OTHERWISE EXPECT DRY WEATHER WITH THE UPPER
LOW IN THIS POSITION. SOME GUSTY OFFSHORE FLOW MAY DEVELOP TUE/WED
OVER NORTHERN PORTIONS OF THE CWA AS WELL...BUT MODELS DO NOT SHOW
IT PERSISTING OR BECOMING WIDESPREAD. RELATIVE HUMIDITY REMAINS
MODERATE AS WELL.
CONFIDENCE LOWERS IN THE EXTENDED PERIOD AS THE GLOBAL MODEL
SOLUTIONS DIVERGE. BASED ON THE LATEST 12Z GFS/ECMWF RUNS...EXPECT
DRY AND SEASONAL...TO SLIGHTLY WARMER THAN AVERAGE WEATHER FOR THE
LATTER HALF OF NEXT WEEK.
&&
.AVIATION...
172030Z...COASTS/VALLEYS...SCATTERED LOW CLOUDS RANGING FROM 1500 FT
MSL TO 3500 FT MSL ARE BANKED UP AGAINST THE COASTAL MOUNTAIN
FOOTHILLS. THESE LOW CLOUDS ARE EXPECTED TO THICKEN AND BECOME
BKN/OVC TONIGHT...FILLING THE COASTAL BASIN. LIGHT DRIZZLE IS
POSSIBLE AFTER AROUND 0600Z. THIS CLOUD DECK WILL ONCE AGAIN
SCATTERED OUT BETWEEN 18/1600Z-1900Z.
MOUNTAINS/DESERTS...SCT CLOUDS IN THE 7000-12000 FT MSL LAYER IN THE
MOUNTAINS. A FEW SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
DEVELOP...MAINLY OVER ELEVATED TERRAIN...THROUGH THIS EVENING.
BASES 5000-8000 FT MSL...TOPS 15000 FT MSL AND CB TOPS TO 35000 FT
MSL. THESE STORMS MAY PRODUCE GUSTY DOWNDRAFT WINDS OF 25-35 KT. VIS
LOCALLY REDUCED TO 3-5SM IN HEAVIER SHRA/TSRA.
&&
.MARINE...
130 PM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH WEDNESDAY.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH FROM NOON PDT TODAY THROUGH THIS EVENING FOR
APPLE AND LUCERNE VALLEYS-SAN BERNARDINO COUNTY MOUNTAINS.
PZ...NONE.
&&
PUBLIC...JAD
AVIATION/MARINE...JTThe Santa Ana Mts radar (KSOX), 48 km away, was scanning. The volume nearest the first event began at 21:40 UTC.
1 tornado. Local standard time, as filed.
Numerous reports through the broadcast media and social media of a brief landspout near Menifee. The funnel was nearly stationary and occurred over open terrain, with no damage reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2015Every state in 2015This day in weather historyThe tornado archive for California, 2015Warnings in California, October 2015
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: 605186.