textproduct: San Joaquin Valley

KEY MESSAGES

1. Temperatures will be normal to slightly below normal through the weekend before below average by the middle of next week.

2. Remaining moisture over the region bring a 5-15% chance of thunderstorms from the foothills to the Sierra Nevada Crest this afternoon.

3. Precipitation chances return again in the middle of next week.

DISCUSSION

Current satellite imagery shows high clouds moving over Central California as the last of the tropical moisture from the past few days continues to the northeast. These clouds should clear out by this afternoon or evening. There is still a 5-15% chance for thunderstorms over the Sierra Nevada this afternoon due to this remaining moisture before dropping below 5% for the rest of the week.

For the next few days, a trough is expected to move over the northwestern coast, causing lowered 500mb heights in much of California. This will lead to a slow cooling trend beginning tomorrow as that trough moves east, though the minRHs around the region will stay dry (15-25% in the Valley and becoming single digits in the desert) through Monday. By the middle of the week, a stronger shortwave is expected to move around the trough, digging further south and leading to much cooler temperatures and increased minRHs. This wave also has the slight chance to bring in a small amount of rainfall to southeastern Kern County on Tuesday. The late week may see another wave of energy move through, by Friday into next weekend. This wave may also bring some precipitation, this time to the Sierra Nevada north of Tulare County.

Looking to the long term forecast, this troughing pattern may persist into the early week after next, leading to either near normal or below normal temperatures depending on how far south they may dig. This pattern would also lend to a more above normal amount of precipitation, which is also shown with the Climate Prediction Center having Central California under a leaning above normal for both the 6 to 10 and 8 to 14 day outlooks.

AVIATION

VFR conditions prevailing for the next 24 hours. However, 5 to 15 percent probability of thunderstorms over the Sierra Nevada between 18Z Saturday and 3Z Sunday.

AIR QUALITY ISSUES

None.

CERTAINTY

The level of certainty for days 1 and 2 is high. The level of certainty for days 3 through 7 is medium.

Certainty levels include low...medium...and high. Please visit www.weather.gov/hnx/certainty.html for additional information and/or to provide feedback.

HNX WATCHES/WARNINGS/ADVISORIES

None.