An east Pacific storm approached California on April 14th, weakening the ridge and cooling temperatures several degrees. Winds increased during the day as a cooler airmass pushed into the San Joaquin Valley and the upper-level jet stream aligned with the passes and canyons of the Kern County mountains. Winds gusted to 80 mph at Bird Springs Pass in the Kern County Sierra Nevada, and to 62 mph at North Edwards Auxiliary Airfield, Edwards AFB. Elsewhere in the mountains and deserts, several wind gusts were in the 45-55 mph range, and gusty winds persisted into the 15th. With dry conditions, blowing dust proved to be a problem in the Kern County deserts. In the San Joaquin Valley, winds gusted to 25-30 mph at several sites, mainly in the central and southwestern San Joaquin Valley.
Gusty winds continued on April 16th as a low-level jet stream moved into the state along the back side of the storm. The jet stream was oriented mainly north-south, and funneled through the mountain passes and canyons. Winds gusted to 45-55 mph in the Kern County mountains and deserts, and to 35-40 mph in the central and southern San Joaquin Valley. The 16th also saw precipitation falling in the mountains. Snow levels were low, around 3600 feet. Snow fell at Ponderosa Basin (elevation 3600 feet), and the California Highway Patrol reported light snow falling, but not sticking, at Lebec (elevation 3585 feet). On the morning of April 17th, Ponderosa reported a 24-hour total of an inch of new snow. In addition to being cold, the airmass was unstable and a few thunderstorms developed near Bass Lake on the 16th.
An upper-level ridge began building into California on April 18th, and temperatures warmed to near normal on the 18th, then well above normal from the 19th through the 27th. High temperatures in the central and southern San Joaquin Valley reached the mid 80s to around 90 on April 21st, and the warmest locations in the Kern County deserts reached the lower 90s. High temperatures were a couple of degrees warmer on the 22nd, with both Bakersfield and Fresno reaching the 90-degree mark for the first time since October 18th, 2012. The high at Fresno was 91 degrees, and Bakersfield was a degree cooler.
A weak cold front dropped into the Great Basin on April 23rd, bringing a push of colder air into the deserts. Temperatures fell as much as 10 degrees from the 22nd to the 23rd at some desert sites. A weaker influx of cool air into the San Joaquin Valley dropped temperatures in the central Valley by a few degrees on the 23rd, with highs falling back into the mid 80s. The cool air did not penetrate as far as the south end of the San Joaquin Valley, and Bakersfield had a second consecutive day with a high of 90 degrees.
Ahead of the cold front, winds increased in the Kern County mountains and deserts during the evening of April 22nd. Gusts were as high as 49 mph, but were not persistent. Wind speeds would jump to over 40 mph, then drop down to 20-25 mph the next observation before increasing again.
April 24th saw the central California interior between two weather features���an upper-level low southwest of the Channel Islands and a short-wave moving through northern California. Mid-level moisture wrapping around the low moved into the region from the east, while the flow down the back of the short-wave was from the northeast. The two flows collided over Madera County, setting up a convergence zone that supported isolated late afternoon convection over the high country of the Southern Sierra Nevada in northeastern Madera County. At the same time, the aforementioned features allowed the coastal marine layer to deepen. The marine layer was over 4300 feet deep at Fort Ord during the afternoon of the 24th, and marine air spilling through the passes and canyons of the Temblors and Diablo Range triggered 35-40 mph gusts along the west side of the San Joaquin Valley during the late afternoon and evening.
The influx of cool air into the San Joaquin Valley produced a noticeable drop in temperatures on the 25th. The high at Bakersfield only reached 79 degrees, the first time since April 18th that the high at Meadows Field did not reach 80 degrees. Fresno was slightly warmer with a high of 81 degrees, down 10 degrees from the previous day. (Bakersfield���s high was down 9 degrees from the 24th.)
High pressure rebuilt into California beginning on April 26th, with temperatures warming through the 29th. A mainly dry upper-level short-wave dropped through California on the 28th, triggering a thunderstorm over the Sierra Nevada crest in Tulare County, and bringing breezy conditions to the west side of the San Joaquin Valley as well as through and below the passes of the Kern County mountains. Winds gusted up to 42 mph at both Cache Creek and Mojave, and to 37 mph at Ridgecrest.
A stronger upper-level trough moved through northern California on April 30th. Short-waves moving along the periphery of the trough brought narrow bands of high clouds that pushed south across the central California interior. The short-waves also brought gusty winds to the region. Gusts reached 35-40 mph on the west side of the San Joaquin Valley, and 45-50 mph below favorably oriented passes and canyons of the Kern County mountains.
Although the trough brought a cooler airmass to the region, April ended on a warm note as Fresno set a record high minimum temperature on the 30th. Despite only setting two temperature records for the month���both high minimums and one being a tie���Fresno had its warmest April on record. (Fresno temperature records go back to 1887; rainfall records go back further, to 1878.) Bakersfield set no temperature records during April, but did tie its 14th warmest April on record (since 1889).

High Wind in SE KERN CTY DESERT, CALIFORNIA
From 13-APR-13 18:00:00 to 14-APR-13 12:00:00 (PST-8)
Magnitude: 51.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet