textproduct: San Joaquin Valley

KEY MESSAGES

1. There is a 30 to 40 percent percent chance of dense fog to form in portions of the San Joaquin Valley early Sunday morning.

2. A low pressure system brings chances of precipitation over the Sierra Nevada on Sunday and Monday with snow levels at 7,000 to 8,000 feet.

3. A Wind Advisory has been issued from Sunday morning through Monday evening due to expected gusty winds along the Mojave Slopes and into the Desert.

DISCUSSION

Temperatures were at least a few degrees warmer than yesterday, or about 10-15 degrees above seasonal averages. Temperatures at this time remain in the 70's at the warmest locations, including in the San Joaquin Valley. Many locations reached into the 80's. Temperatures will be on the downtrend for Sunday, but expect highs to top 80 degrees once again at some locations in Kern County on Sunday (probabilities in the south valley are at 70-80 percent and 30-40 percent in the desert areas). A moderate chance (30-40 percent) at best exists for dense fog to form in the Central Valley by early Sunday morning, although latest high resolution guidance suggests visibility in most areas will remain above one quarter of a mile. As temperatures were warmer today, it will take some time for fog development. Any fog that develops will be patchy and shallow, generally about 2-3 hours on each side of sunrise. Latest guidance suggests mainly clear conditions over the remainder of the forecast area tonight.

For Sunday, a low pressure system approaches and brings the next chance for precipitation. However, precipitation will be light, although there is moderate to high confidence (60-70 percent chance) that we will see a tenth of an inch over the Sierra Nevada and adjacent foothills. The possibility of any location receiving at least 0.25 inch is much lower, or about 20-30 percent in the highest elevations. Snowfall amounts are generally a dusting up to an inch with snow levels of 7,000 to 8,000 feet. There is also a 10 percent chance for an isolated thunderstorm by the afternoon over Yosemite NP. Chances for light lingering showers will last until Monday afternoon. Otherwise, it is more certain that cooler temperatures and gusty winds develop over the Sierra Nevada crest and Kern County mountains and desert with a high probability (70-80 percent chance) of gusts at least 40 mph.

Another low pressure system brings a slight chance for Sierra precipitation on Wednesday into Thursday along with another round of increased winds. Otherwise, dry conditions and seasonal temperatures prevail for the next several days. Latest CPC outlooks continue to show at least a slight tilt in the odds towards below average precipitation and above average temperatures for the 6-10 day and 8-14 day periods.

AVIATION

VFR conditions will prevail across the Central California interior for the next 24 hours with a 40-50% chance for IFR/LIFR conditions from 10Z through 16Z Sunday for the San Joaquin Valley.

AIR QUALITY ISSUES

None.

CERTAINTY

The level of certainty for days 1 and 2 is medium. 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

Wind Advisory from 10 AM Sunday to 10 PM PST Monday for CAZ337>339.