textproduct: San Joaquin Valley

KEY MESSAGES

1. Warmer and drier Thursday and Friday.

2. A low pressure system brings chances for precipitation and minor thunderstorm risks this weekend.

3. A second low pressure system approaches the area early next week.

DISCUSSION

Quieter weather returns Thursday and Friday as quasi-zonal flow establishes itself over the area. This will allow for dry and pleasant conditions, with high temperatures across the Valley in the low- to upper-70s Thursday and mid-70s to low-80s Friday.

A trough will approach the coast this weekend, bringing with it chances of thunderstorms and precipitation. As this first trough moves out of the area, a second trough will form off the coast, keeping the area in a general troughing pattern before it moves onshore. The first trough will bring a 5-10% chance of a wetting rain to the eastern half of the Valley both Saturday and Sunday, increasing to 10-20% in the Sierra foothills. The eastern half of the Valley can also expect a 5-10% chance of thunder both Saturday and Sunday, with a 10-20% chance in the Sierra foothills. This will also create windy and elevated fire conditions in southeastern Tulare and eastern Kern Counties Friday and Saturday, with a 40-70% chance of gusts exceeding 55 mph during the period. The Sierra Nevadas have a 50-70% chance of at least an inch of snow at low elevations, with a 70-80% chance of at least three inches at higher elevations.

Current models show the second trough beginning to approach the area before the first trough fully leaves, which will keep a constant threat of thunderstorms (5-10%) across the eastern half of the Valley and into the Sierra foothills Sunday and into Monday. As this second trough approaches, this threat will grow to encompass the entire area by Tuesday. This may also introduce a wind and fire threat. This continuous troughing will keep temperatures near or a bit below normal through the weekend and into next week.

AVIATION

VFR conditions are expected for the next 24 hours in the San Joaquin Valley.

AIR QUALITY ISSUES

Reduced flow and ventilation will allow for minor air stagnation that may cause issues in vulnerable populations.

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.