textproduct: San Joaquin Valley

UPDATE

Aviation section updated.

KEY MESSAGES

1. Dry and breezy conditions create elevated fire risk this week, especially in the Mojave Desert.

2. Slight chance for thunderstorms this afternoon along the Sierra Crest from Yosemite NP to Sequoia and Kings Canyon NP.

3. Below normal temperatures continue across the area.

4. Practice safety around lakes, rivers and streams, as water is still running cold.

DISCUSSION

A troughing pattern over much of the western United States is maintaining from the weekend, resulting in clear, dry conditions for central California with relatively cool temperatures near season averages. This pattern is expected to continue for much of the work week, but gradually weakening as the holiday weekend approaches. As such, a slight warming trend is expected later this week, with a 60 to 70 percent probability for maximum temperatures to exceed 95 degrees on Saturday in the San Joaquin Valley; until then, there is less than a 20 percent probability for these highs. However, with the prevailing flow entering the region from the northwest, drier air is anticipated to continue, with daily minRH values across the valley areas at 20 percent or less and desert values between 10 and 15 percent; minRHs at the higher Sierra elevations will also be around 15 to 20 percent with greater RHs in the 30s for the foothills.

Before getting into the rest of the week, a shortwave low pressure system is currently breaking off from the main trough and will continue through central California today. The increased dynamics from the system and relatively stronger moisture influence will bring a slight chance for thunderstorms across the crest of the Sierra Nevada this afternoon. Any storm that may develop can contain cloud-to- ground lightning, gusty and erratic winds, small hail, and intense rainfall rates.

AVIATION

VFR conditions expected across the area for the next 24 hours. 10% chance for isolated thunderstorms across the Sierra Crest until 4Z 29-Jun (21PDT Jun 28).

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 Thursday for CAZ300.