An upper-level cold front passed through the northern San Joaquin Valley around noon Thursday, giving Turlock some moderate rain. After the front passed, temps remained in the mid to upper 60s, dewpoints were still in the mid to upper 50s, and winds were southerly - but temps aloft had cooled. Showers and thunderstorms popped up all over the Sacramento/Stockton area by 1400. At 1600, I left Turlock to take a look at the storms in the Stockton area.
My original chase plan was to take Hwy 99 north up to Stockton, then turn right and head east on Hwy 26. But as I approached Manteca, it looked as if Hwy 26 would be too far north to get the best view of the storms. I wanted to be to the south and west of these storms, so I decided to turn off Hwy 99 in Manteca and begin heading east on Hwy 120.
At 1640, the radio station I was listening to mentioned that a severe t'storm and flash flood warning had just been issued for extreme eastern San Joaquin County. I was on Hwy 120 between Manteca and Escalon at this time. I continued east on Hwy 120 until Escalon, then turned left on Route J6 and headed north towards the warned storm.
As I left Escalon, I began hearing almost continuous static on the AM radio from this storm. I could also see a heavy hailshaft a few miles to my E, which appeared to be over Woodward Reservoir in northern Stanislaus County. Since the main core of this storm was to my E, I was able to stay out of the precipitation. But between Milton Rd and Flood Rd, I did get into a heavy cell. Lightning activity by this time (1705-1710) had decreased to occasional in-cloud variety, but the rain was extremely heavy - with a little bit of 1/8 inch hail mixed in. After exiting this cell, I continued on Route J6 until it ended at Hwy 26 - then turned left on Hwy 26 and headed home.
Turned out there was more interesting weather on the drive home. I got into another thunderstorm between Stockton and Modesto - with four individual pockets of intense rainfall. Lightning activity was rather infrequent, though - with crackles on the radio once every few minutes. And things still looked interesting in Turlock once I got home at 1815 - temp 66F, dewpoint 56F, winds still southerly, and four TCu building along a SW-NE line just south of town. But a weak boundary came in from the W at sunset, pushing these TCu off to the E.
Since the cell I chased was over a hilly, uninhabited area - there was no mention of it on the news Thursday evening. Sacramento TV stations did have some decent coverage of the storms in the Sacramento area - including footage of pea to marble-sized hail and possible tornado damage.* A funnel cloud was reported in Sacramento on Thursday afternoon, but apparently nobody got it on video.
It's remained warm and a bit muggy all night, winds have switched back to a southerly direction, and there's been enough instability for a few more light showers early this morning. Could we have a repeat of yesterday's storminess later on today? We'll see...
Follow up....The National Weather Service in Sacramento confirmed the next day that a tornado touched down in Sacramento.