textproduct: San Joaquin Valley

KEY MESSAGES

1. Minor Heat Risk through the weekend into Monday as temperatures cool to early fall normals. Temperatures climb beginning Tuesday.

2. Low pressure trough approaches California Sunday, bringing cooler temperatures and a possibility for precipitation along the Sierra Nevada mountains.

3. Low but notable chances (10-20%) for thunderstorms across the Sierra Nevada Monday.

4. Lake Wind Advisories for Lake Isabella and San Luis Reservoir through late this evening.

DISCUSSION

A rather strong disturbance is expected to arrive over the region during the day on Sunday. Currently, satellite imagery is showing higher clouds in a southwesterly flow pushing in ahead of the disturbance as cooler temperatures and an increase in moisture is already being felt. While the center of the disturbance will reside over Sacramento, enough energy will push into Central California and provide the district will a significant cool-down and strong winds. By Sunday, PoE of reaching 90 degrees is still showing a drop below 30 percent (outside of Bakersfield) with most afternoon high values expected in the upper 80s. At the same time, Wind Gusts PoE of reaching above 35 mph increases over the favored spots as places like Mojave and Ridgecrest are expected to have percentages in the 50-70 percent range.

Monday is still showing a change in the weather as the strong (deep) upper level disturbance will cut across California. While moisture from Hurricanes Polo and Odalys surge into the Baja California and Desert Southwest area, the timing of the disturbance interacting with the moisture will limit the moistures ability to surge deep into Central California. Currently, longer-term analysis does show wrap-around moisture able to push northwest and into the the Sierra Nevada, as the mountains will see an increase in moisture. Again, while limited, ensemble precipitation analysis does placed a chance of showers (and thunderstorms) on Monday. At the same time, PoE of reaching 90 degrees bottoms out at near zero as the cooler air overspreads much of the district. Therefore, with less of a temperature gradient from the valley to the desert, winds are also expected to diminish starting on Monday.

Latest ensemble model consensus is still showing the disturbance east of the region by Tuesday as ridging returns to the West Coast. A warming trend with dry conditions will enter on Tuesday and persist for much of the period. Climate Prediction Center is placing Central California in the Likely Above Normal Temperatures categories for both 6 to 10 Day and 8 to 14 Day periods. At the same time, Precipitation is expected to remain at Near Normal values.

AVIATION

VFR conditions will prevail for the next 24 hours.

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

Lake Wind Advisory until 11 PM PDT this evening for CAZ300.