A high pressure ridge expanded back into California on August 22nd. Monsoonal moisture rotating around the ridge core brought mid and high clouds to central California on the 22nd, and again the next day.
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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 HNX wrote it up.
A high pressure ridge expanded back into California on August 22nd. Monsoonal moisture rotating around the ridge core brought mid and high clouds to central California on the 22nd, and again the next day. The region was between the ridge and a closed low over the Pacific west of the California coast. This pattern kept a southerly flow aloft over the central California interior, bringing more monsoonal moisture into the region. Thunderstorms developed over the Southern Sierra Nevada on August 24th, producing numerous lightning strikes but little rainfall.
The upper-level ridge core began to shift westward from the Desert Southwest, bringing an increase in temperatures and moisture to move into interior central California by the 26th. Some sprinkles fell in the southern San Joaquin Valley, even from Bakersfield and northward into Hanford and Tulare. A spotter in downtown Bakersfield recorded a measurable rainfall of 0.01 inch, but most locations, including Meadows Field, received only trace amounts. On the following day, two severe thunderstorm warnings were issued for locations in the Indian Wells Valley in Kern County, mainly around Ridgecrest and Inyokern. A 58 mph wind gust was recorded at Indian Wells Canyon, or about 15 miles northwest of Ridgecrest, on the 27th. Flash flooding occurred on Garlock Road just west of U.S. Highway 395, about 20 miles south of Ridgecrest, on the same day.
By the 28th, upper-level winds shifted back to the southwest and allowed drying to commence in the region, except a few isolated thunderstorms developed along the crest of the southern Sierra Nevada. Dry weather returned by the 29th since the moisture moved to the east of the state, and slight cooling occurred throughout the region due to a weak trough over the area on the 30th and 31st.
The month of August was overall dry and slightly above average in terms of temperature throughout the region. A few thunderstorm days occurred intermittently throughout the month in the higher elevations of the Southern Sierra Nevada and the mountain and desert areas in Kern County as the upper-level ridge centered the Desert Southwest repeatedly expanded westward and then contracted in response to upper-level troughs passing through the state. Bakersfield had 9 days with triple digit heat, bringing its total for the summer, through August 31st, to 25 days. Fresno had 11 days of 100+ degree high temperatures in August, bringing its total, through the end of August, also to 25 days.
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 Hanford, CA wrote its last area forecast discussion before the first event at Aug 27, 1:50 PM PST, 2 hours 39 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 250 PM PDT SAT AUG 27 2011 .SYNOPSIS... HIGH PRESSURE RIDGING WILL DOMINATE THE WEATHER PATTERN FOR THE REMAINDER OF THE WEEKEND WITH WARMER THAN NORMAL TEMPERATURES. MID LEVEL MOISTURE WILL CONTINUE OVER THE REGION ALONG WITH A SLIGHT CHANCE OF THUNDERSTORMS OVER THE MOUNTAIN AND DESERT AREAS THROUGH THE WEEKEND. THE RIDGE IS EXPECTED TO WEAKEN EARLY NEXT WEEK WITH TEMPERATURES NOTICEABLY COOLER BY MID-WEEK. && .DISCUSSION... REGIONAL DOPPLER RADARS SHOWING ISOLATED CONVECTION FLARING UP THIS AFTERNOON...MAINLY ALONG THE SIERRA NEVADA CREST AND THE SOUTHERN SLOPES OF THE TEHACHAPI/S. BASED ON THE AREA OF INSTABILITY AND OROGRAPHIC LIFT THIS AFTERNOON...WILL EXPECT THE CONVECTION TO REMAIN CONFINED TO THE MOUNTAIN REGIONS. IN ADDITION...SHORT RANGE MODELS STILL PROGGING A WEAK SHORT WAVE TROF RIDING AROUND THE FOUR CORNERS RIDGE AND PUSHING THROUGH THE EASTERN SIDE OF THE DISTRICT THIS EVENING. THIS TROF MAY GIVE THE MOUNTAINS ADDITIONAL LIFT TO SUPPORT EVENING CONVECTION BEFORE DIMINISHING OVERNIGHT. BY SUNDAY MORNING...MODELS PROG FRIDAY AFTERNOON/S UPPER LOW OVER THE PACIFIC NORTHWEST AS THE FOUR CORNERS RIDGE CONTINUES TO BUILD WESTWARD. THEREFORE...WILL EXPECT AN EVEN WARMER DAY ON SUNDAY BEFORE THE UPPER LOW MOVES FROM THE PACIFIC NORTHWEST TO THE INTER MOUNTAIN WEST. BY SUNDAY AFTERNOON...THE FLOW ALOFT WILL STILL BE SOUTHERLY AND ALLOW FOR A CONTINUATION OF THE MONSOONAL AIRFLOW. THEREFORE...WILL CONTINUE TO MENTION SLIGHT CHANCES OF AFTERNOON THUNDERSTORMS FOR ONE MORE DAY. BY SUNDAY NIGHT...THE FLOW ALOFT BEGINS TO CHANGE IN RESPONSE TO THE TRAVELING UPPER LOW WHICH WILL GIVE THE REGION A BETTER ONSHORE FLOW PATTERN AND RESULT IN A DRYING AND COOLING TREND. SHORT RANGE ENSEMBLES AGREE WITH THIS CHANGE AS IT SHOW VERY LITTLE UNCERTAINTY WITH THE PLACEMENT OF THE UPPER LOW TOWARD NEXT MONDAY ALONG WITH A SECONDARY TROF PUSHING INTO NORTHERN CALIFORNIA. BY WEDNESDAY...THE MAIN AREA OF THE SECONDARY TROF THAT BEGIN PUSHING INTO THE AREA EARLIER IN THE WEEK WILL DEEPEN AND PUSH CLOSER TO THE NORTHWEST WASHINGTON COAST. WITH DEEPENING TROF WILL INCREASE THE STRENGTH OF THE ONSHORE FLOW PATTERN AND CONTINUE THE COOLING TREND OVER CENTRAL CALIFORNIA. AT THIS POINT...WILL EXPECT TEMPERATURES TO BECOME MORE SEASONAL AS DRY COOL AIR FILTERS IN FROM THE COAST. TOWARD THE END OF THE COMING WEEK...LONGER RANGE MODELS SHOW THE UPPER TROF MOVING INTO THE NORTHERN ROCKIES AND CONTINUE THE ONSHORE FLOW PATTERN. BY NEXT WEEKEND...THE FLOW STARTS ITS SHIFT TOWARDS A MORE SOUTHERLY DIRECTION AS THE RIDGE REBOUNDS. AT THIS POINT...WILL NOT INTRODUCE ANY PRECIP OVER THE DISTRICT BY NEXT WEEKEND AS THE WESTERLY COMPONENT OF THE FLOW ALOFT IS STILL TOO DOMINATE FOR A RETURN OF THE MONSOON. && .AVIATION... THE MONSOON FLOW WILL KEEP A MOIST AIRMASS ACROSS THE AREA WITH ISOLATED THUNDERSTORMS OVER THE MOUNTAINS AND DESERT AREAS THROUGH 04Z THIS EVENING...AND POSSIBLY A FEW DEVELOPING NEAR THE SIERRA CREST AFTER 18Z SUNDAY. OTHERWISE...VFR CONDITIONS ARE EXPECTED ACROSS THE CENTRAL CALIFORNIA INTERIOR THROUGH 00Z MONDAY. && .AIR QUALITY ISSUES...ON SATURDAY AUGUST 27 2011... UNHEALTHY FOR SENSITIVE GROUPS IN FRESNO...KERN...MADERA AND TULARE COUNTIES. FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG && .HNX WATCHES/WARNINGS/ADVISORIES... NONE. && PUBLIC...MOLINA AVN/FW...JEB SYNOPSIS...BSO WEATHER.GOV/HANFORD
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY CA
333 PM PDT SAT AUG 27 2011
CAZ099-272315-
KERN CA-
333 PM PDT SAT AUG 27 2011
THE NATIONAL WEATHER SERVICE IN HANFORD HAS ISSUED A
SIGNIFICANT WEATHER ADVISORY FOR...
SOUTHEASTERN KERN COUNTY IN CENTRAL CALIFORNIA
UNTIL 415 PM PDT
AT 324 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 14 MILES SOUTH OF
EDWARDS AFB TO 19 MILES SOUTHEAST OF CALIFORNIA CITY..AND MOVING
NORTHWEST AT 25 MPH.
WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THESE STORMS...ALONG WITH
HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING.
LOCATIONS IMPACTED INCLUDE...
EDWARDS AFB...
CALIFORNIA CITY...
LAT...LON 3481 11765 3482 11814 3503 11820 3533 11766
3528 11762 3484 11762
TIME...MOT...LOC 2233Z 143DEG 22KT 3476 11806 3506 11758
DUDLEYThe national radar mosaic for the moment the first event began.
1 thunderstorm wind, 1 flash flood. Local standard time, as filed.
A severe thunderstorm created wind gusts of 58 mph at Inyokern.
The California Highway Patrol reported flash flooding across Garlock Road just west of US Highway 395.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2011Every state in 2011This day in weather historyWarnings in California, August 2011
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: 345747, 345746.