Monsoonal moisture in easterly flow aloft brought showers and thunderstorms to the mountains and deserts each afternoon and evening. The activity on the 9th was mainly in the upper deserts, San Bernardino Mountains and the Inland Empire near Lake Elsinore. Flooding was reported along Highway 74 in Lake Elsinore with 3 to 5 inches of water covering the roadway, along with several downed trees, and a land spout in the nearby city of Perris. Outflow boundaries from storms created strong winds which picked up dust and lowered visibility in the Coachella Valley and near Borrego Springs. Visibility was also lowered to near zero at times with wind gusts around 60 MPH reported in the areas. Storms were more widespread on the 10th as a trough of low pressure drifted north from Mexico. Thunderstorms occurred over most mountain and desert locations, as well as the Inland Empire. Flash flooding was reported in Forest Falls and along Highway 76 in northern San Diego County. Highway 76 was closed for about an hour in the afternoon due to 12 to 18 inches of mud and debris in the road.

Flash Flood in SAN BERNARDINO, CALIFORNIA
From 10-SEP-12 12:00:00 to 10-SEP-12 13:00:00 (PST-8)
Location: FOREST FALLS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Mill Creek in Forest Falls was running 100 feet wide  at one point with significant debris flowing with it. Police evacuated some people in the town of Forest Falls.
The Yucaipa Ridge mesonet station recorded approximately 3 inches of rain between 1130 and 1230 PST. The Heart Bar mesonet station, in the mountains upstream of Mill creek, recorded 2.84 inches of rain during that same hour.

Heavy Rain in SAN DIEGO, CALIFORNIA
From 10-SEP-12 13:00:00 to 10-SEP-12 14:15:00 (PST-8)
Location: PALOMAR MTN
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The mesonet station of Eastern Tanks at La Jolla Amago recorded 1.46 inches of rain between 1311 and 1400 PST.
The mesonet station at the La Jolla Indian Reservation recorded 1.54 inches of rain between 1317 and 1405 PST.

Flash Flood in SAN BERNARDINO, CALIFORNIA
From 10-SEP-12 13:45:00 to 10-SEP-12 14:45:00 (PST-8)
Location: HELENDALE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

A combination of debris and 6 inches of water flowing across National Trails Highway at Barbosa Road caused several vehicles to get stuck, resulting in CHP closing the highway for approximately 2 hours.
National Trails Highway was also closed at Hodge Road due to flooding.

Flash Flood in SAN DIEGO, CALIFORNIA
From 10-SEP-12 14:30:00 to 10-SEP-12 15:30:00 (PST-8)
Location: PAUMA VLY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Highway 76 east of Rincon was closed for one hour from 1430 to 1530 PST due to a flash flooding-induced debris flow 12-18 inches deep on the roadway.

Flood in SAN DIEGO, CALIFORNIA
From 10-SEP-12 14:30:00 to 10-SEP-12 15:00:00 (PST-8)
Location: RAMONA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter SDG447 reported 0.84 inches of rain between 1430 and 1500 PST, which resulted in flooded roadways in the San Diego Country Estates area.

Thunderstorm Wind in SAN DIEGO, CALIFORNIA
From 09-SEP-12 16:00:00 to 09-SEP-12 17:00:00 (PST-8)
Location: PAUMA VLY
Magnitude: 36.00 MG
Property damage: 6.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law Enforcement reported an oak tree blown down across Lilac Rd near the intersection of San Luis Rey Drive. A newspaper article reported additional trees blown down across Lilac Road near the intersection of Couser Canyon Road.
A NWS employee reported three large pine trees downed by wind along Highway 76 south of Palomar Mountain. The largest of the uprooted pine trees was 18 to 20 inches in diameter, and healthy. A weather spotter estimated a 40 MPH wind gust in the area. The SDGE weather station at Cuca Ranch reported a wind gust of 42 MPH just before 1630 PST.

High Wind in COACHELLA VALLEY, CALIFORNIA
From 09-SEP-12 19:00:00 to 09-SEP-12 20:00:00 (PST-8)
Magnitude: 53.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Wind gusts at the Thermal ASOS gusted over 45 mph between 1916 and 1944 PST with a peak gust of 61 mph at 1928 PST. The ASOS reported visibility between three-quarters of a mile and 3 miles in blowing dust during that time frame.

Dust Storm in COACHELLA VALLEY, CALIFORNIA
From 09-SEP-12 19:00:00 to 09-SEP-12 20:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Strong winds and low visibility in blowing dust forced several vehicles to pull over on Highway 86 in Mecca. The Department of Highways reported visibility of three-quarters of a mile at 1925 PST near Mecca. The ASOS reported visibility between three-quarters of a mile and 3 miles during that time frame. The Palm Springs ASOS also reported visibility between one-quarter and one-half mile with winds gusting to 47 mph between 1948 and 2053 PST. A spotter in Cathedral City also reported visibility down to one-eighth of a mile in blowing dust with wind gusts to 36 mph.

Flood in RIVERSIDE, CALIFORNIA
From 09-SEP-12 21:00:00 to 09-SEP-12 22:00:00 (PST-8)
Location: SAN JACINTO
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A spotter reported four inches of water on Mountain Avenue in the city of San Jacinto near Hemet. The Riverside County sheriff closed the roadway.
A mesonet station in the Valle Vista/Hemet area recorded a one-hour rainfall amount of 0.81 inches.

Flood in RIVERSIDE, CALIFORNIA
From 09-SEP-12 13:30:00 to 09-SEP-12 14:30:00 (PST-8)
Location: DURANT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

An NWS employee reported 3 to 5 inches of water flowing across the intersection of highway 74 and Lincoln in Lake Elsinore.

Flood in SAN DIEGO, CALIFORNIA
From 10-SEP-12 10:45:00 to 10-SEP-12 12:45:00 (PST-8)
Location: LIVE OAK SPGS
Flood cause: Heavy Rain
Property damage: 9.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A heavy downpour resulted in standing water on Interstate 8 between Boulevard and Inkopah, as well as along portions of Highways 80 and 94 in that area.
Small hail of one-quarter of an inch or less and reduced visibility in heavy rain also occurred with this storm.
The Border Patrol station in Boulevard suffered damages from the heavy rain as well when mud was forced through the doors into the garage.
Between 1050 and 1250 PST, the Boulevard mesonet station recorded 0.71 inches of rain.

Tornado in RIVERSIDE, CALIFORNIA
From 09-SEP-12 13:00:00 to 09-SEP-12 14:00:00 (PST-8)
Location: PERRIS
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A land spout was observed at 1330 PST along interstate 215 and highway 74 in Perris. No funnel was observed at the cloud base, and the land spout remained nearly stationary. Pictures and a video were submitted by spotters.

Thunderstorm Wind in RIVERSIDE, CALIFORNIA
From 09-SEP-12 13:45:00 to 09-SEP-12 14:15:00 (PST-8)
Location: DURANT
Magnitude: 48.00 EG
Property damage: 0.50K
Crop damage: 0.00K
Reported by: NWS Employee

NWS employee reported 2 to 3 inch thick tree limbs down due to thunderstorms in Lake Elsinore around 1400 PST. Wind gust estimated around 55 MPH.

High Wind in SAN DIEGO COUNTY DESERTS, CALIFORNIA
From 09-SEP-12 19:15:00 to 09-SEP-12 19:45:00 (PST-8)
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The SDGE station at Borrego Springs measured sustained winds of 34 mph with gusts to 60 mph at 1930 PST. Law enforcement reported visibility of less than one-sixteenth of a mile (300 feet) in blowing dust during that time.