An upper-level disturbance that moved across central California during the night of August 17th-18th brought enough instability to the monsoonal moisture aloft to trigger widespread light showers across the central California interior. By sunrise, lightning had been reported in Clovis and in the Southern Sierra Nevada foothills near Coarsegold. The clouds also kept low temperatures abnormally warm, with Bakersfield having a low of 80 on August 18th, and Fresno a low of 75. Both set high minimum temperature records for the 18th. The next day, Fresno tied its record high minimum temperature of 74, a record untouched for more than a century (since 1892).
Thunderstorms developed over the Southern Sierra Nevada and the eastern Kern County desert during the afternoons of August 21st and 22nd. Over 300 lightning strikes were recorded over the Southern Sierra Nevada���mainly near the crest���during the early morning hours of the 22nd, as an upper level low-pressure system moved across central California. Later on August 22nd, as an upper-level low traversed Kern County, a funnel cloud was observed over Ridgecrest during the late afternoon, followed by the development of a very strong thunderstorm near Randsburg less than an hour later. Outflow boundaries from thunderstorms over southeastern Tulare County, southern Inyo County and northwestern San Bernardino County collided to form the equivalent of a standing-wave node just north of Randsburg. This kept the thunderstorm stationary as it strengthened, resulting in very heavy localized rainfall. Flash flooding closed U.S. 395 from near Randsburg north to the Garlock Road as several inches of water flowed across the roadway.  Later that evening, runoff from rain falling on the El Paso Mountains produced minor mud and rock slides on the Red Rock-Randsburg Road.
By August 23rd, an upper-level trough was dropping out of the Gulf of Alaska. As the trough approached the coast late on the 24th, the marine layer began deepening and spilling into the San Joaquin Valley. The shallow layer of marine air that initially pushed into the central and southern San Joaquin Valley finally ended the string of 100-degree days at Fresno. The high at both Bakersfield and Fresno was 98 degrees.
The marine layer continued to deepen through the day of August 25th, and by the evening had a depth in excess of 3000 feet. Marine air began spilling through the passes and canyons of the Temblors and Diablo Range, creating gusts to around 35 mph through and below the Pacheco Pass and near Sunflower Valley. Temperatures in the central and southern San Joaquin Valley continued to cool, with Fresno only reaching a high of 92 degrees on the 26th; Bakersfield was a degree warmer.
Cool temperatures continued on August 27th, and the morning that day was the coldest of the month for both Bakersfield and Fresno. High pressure subsequently began rebuilding into California from the east, with another surge of monsoonal moisture wrapping around the edge of the ridge and moving into southern California. More monsoon-related activity occurred in the desert areas of Kern County and along the crest of the southern Sierra Nevada until the 30th. In fact, some warnings (including one severe thunderstorm and one flash flood warning) were issued on the 30th for Edwards AFB, and a flood advisory was issued for much of the desert in Kern County for the afternoon and evening hours. A wind gust of 67 mph was reported at one station on Edwards AFB on the afternoon of the 30th due to thunderstorm outflow winds. This storm also dumped 0.35 inch of rain in less than an hour at the base.
Temperatures in the central and southern San Joaquin Valley warmed back into the mid to upper 90s on August 28th, and continued to warm until the 30th as the upper-level ridge prevailed over the area. By the 31st, the ridge began to weaken and move eastward as cooler marine air once again began to filter into the San Joaquin Valley; this allowed temperatures to return to near average, or mainly lower to mid-90s for maximum diurnal temperatures, in this area. An upper-level trough allowed for a more westerly flow over the region, so locations elsewhere showed a slight decrease in temperature.
As of August 31st, the average temperature at Fresno was 86.5 degrees, which was 4.8 degrees above normal. This is the warmest August on record for Fresno, the previous warmest being August 1931 with an average temperature of 84.4 degrees. The average temperature at Bakersfield was 87.0 degrees. This would rank as Bakersfield���s fifth warmest August. (For more information, see ���The 10 Hottest Augusts table��� on the next page).
Fresno���s 19-day string of 100-degree days tied for the third longest string of consecutive 100-degree days on record. August 2012 had a total of 23 days when the high temperature reached 100 degrees or more at Fresno; this tied for the second greatest number of 100-degree days for the month of August which also occurred in 1910.

Flash Flood in KERN, CALIFORNIA
From 22-AUG-12 16:38:00 to 22-AUG-12 18:38:00 (PST-8)
Location: SEALERS
Flood cause: Heavy Rain
Property damage: 60.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained storm spotter captured video footage of a flash flood on US 395 near Randsburg and Garlock Roads south of Ridgecrest. Two vehicles were damaged and the highway patrol closed the highway for several hours.

Funnel Cloud in KERN, CALIFORNIA
From 22-AUG-12 15:35:00 to 22-AUG-12 15:35:00 (PST-8)
Location: RIDGECREST
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained storm spotter reported a funnel cloud near Ridgecrest that lasted for a few minutes.