textproduct: San Joaquin Valley

UPDATE

Updated Aviation Section.

KEY MESSAGES

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

2. Low pressure trough moves through California today, 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 again from Sunday afternoon into this evening and morning, respectively.

DISCUSSION

Major trough continues to slide in overnight into Monday, bringing cooler temperatures and some moisture into the area. There is a 80 percent chance and higher of highs below 85 degrees in the Valley. Wind gusts increase in the Valley and mountains over the afternoon with a 5 to 10 percent chance of gusts of 25 mph in the Valley. Lake Wind Advisories are already in effect for Lake Isabella and San Luis Reservoir into Monday evening and morning respectively.

The moisture from the trough helps bring a 10 to 20 percent chance of thunderstorms over the Sierra Nevada. In addition, there is a 10 to 40 percent chance of an inch of snow on Monday above 9,000 feet. The Valley, however, has a 5 percent chance or less of any precipitation. THe foothills have a 10 to 25 percent chance of any rain on Monday. Meanwhile the higher elevations sees a 25 to 50 percent chance of a tenth of an inch of rain.

However, temperatures begin to climb again on Tuesday as the trough slides away. A ridge of high pressure will slide in on Wednesday bringing in a 60 to 80 chance of highs of 95 degrees and higher in the Valley from Thursday into next Monday. Dry conditions will continue to dominate. This holds up with the CPC having a 70 to 90 percent chance of above average temperatures in the 6-10 and 8-14 day outlooks.

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 7 AM PDT Monday for CAZ300. Lake Wind Advisory until 7 PM PDT Monday for CAZ332.