An upper-level ridge built into California behind the departing trough. Temperatures warmed to near normal by April 16th, then above normal the next day. An upper-level trough moved through the Pacific Northwest on the 18th, briefly flattening the ridge, but the ridge rebounded on April 19th for a sharp warming trend. High temperatures in the central and southern San Joaquin Valley on April 20th were 7-10 degrees warmer than the previous day. Temperatures on the 21st continued to warm, and highs were 4-7 degrees warmer than on the 20th. Both Bakersfield and Fresno had their first 90-degree days of the year, with highs of 94 and 93 degrees, respectively.
Temperatures warmed even further on the 22nd; record high maximum and minimum temperatures were either tied or broken at both Fresno and Bakersfield.
The ridge began to weaken by the following evening, with an upper level trough over northern California. This trough ushered in cooler marine air into the San Joaquin Valley and much of interior central California so that temperatures cooled several degrees by the 23rd. (This pattern was similar to what occurs during the summer months.) Temperatures mainly reached the 80s on the 23rd and 24th in the San Joaquin Valley; however, they remained as high as the 90s during these days in the Kern County desert areas where there was little influence from the marine air.
Another low pressure trough approached central California by April 25th, bringing strong thunderstorms to the southern San Joaquin Valley, including Bakersfield and Delano during the afternoon. These storms continued to develop and intensify as they moved northward into Tulare County. The main threat these storms produced was heavy rain; this caused street flooding throughout much of the San Joaquin Valley portion in Tulare County, including Visalia, Tulare, and Porterville. Many locations in Tulare County received from around 0.5 to 1.5 inches of rain where the strongest storms developed.
On the 26th, the colder air infiltrated the region behind the upper-level low. A cold air funnel was spotted in a thunderstorm that developed near Exeter, or about 10 miles east-southeast of Visalia, during the afternoon of the 26th. Much cooler air prevailed through the 27th as temperatures were well below seasonal averages. Subsequently, high pressure gradually began to build over the area. Low clouds persisted in the Sierra Nevada foothills until the 28th due to a cool and somewhat moist northwest flow aloft that continued over the area as the upper-level ridge was slow to move inland. Temperatures on April 28th were several degrees warmer than during the previous day and returned to near seasonal averages.
On the afternoon of the 26th, gusty winds developed in the Ridgecrest area.  A trained weather spotter reported blowing dust with brown out conditions.  Winds were estimated at 55 mph and a small shed was blown over at the Ridgecrest fairgrounds.
The upper-level ridge finally progressed onshore and set up over the region as temperatures warmed back to well above average during the 29th and 30th. The month ended with many locations throughout the San Joaquin Valley and Kern County desert having highs in the 90s due to this upper-level ridge.
THE 2011-2012 RAIN SEASON THROUGH APRIL 30TH
/AMOUNTS IN INCHES/
SITE APR NRML DEP PCT SEASON NORMAL DEP PCT
2012 APR* NRML 4/30 4/30* NRML
MERCED AIRPORT 1.69 0.95 0.74 177.9 7.02 11.79 -4.77 59.5
MERCED CITY 2.23 0.94 1.29 237.2 7.89 12.42 -4.53 63.5
MADERA AIRPORT 1.59 0.95 0.64 167.4 7.87 11.35 -3.48 69.3
FRESNO 2.02 0.95 1.07 212.6 8.15 10.86 -2.71 75.0
HANFORD AIRPORT 1.79 0.79 1.00 226.6 5.79 9.53 -3.74 60.8
HANFORD CITY 1.39 0.78 0.61 178.2 5.71 8.61 -2.90 66.3
BAKERSFIELD 1.62 0.52 1.10 311.5 4.93 6.21 -1.28 79.4
* NORMALS FOR BAKERSFIELD...FRESNO...HANFORD CITY AND MERCED CITY ARE
FOR 1981-2010.
NORMALS FOR HANFORD...MADERA AND MERCED AIRPORTS ARE FOR 2001-2010.
Bakersfield had its 10th wettest April on record. Fresno had its 19th wettest April on record.

Strong Wind in INDIAN WELLS VLY, CALIFORNIA
From 26-APR-12 09:56:00 to 26-APR-12 20:00:00 (PST-8)
Magnitude: 48.00 EG
Property damage: 55.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Funnel Cloud in TULARE, CALIFORNIA
From 26-APR-12 10:45:00 to 26-APR-12 10:45:00 (PST-8)
Location: EXETER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Local law enforcement reported a cold air funnel near Exeter.