textproduct: San Joaquin Valley

KEY MESSAGES

1. Minor Heat Risk across the lower elevations of central California over the weekend and into next week.

2. Increased fire risk through the weekend, particularly Saturday with low relative humidity and moderate winds.

3. Strong winds expected for the Mojave Desert Slopes and the Kern River Valley until Sunday morning.

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

DISCUSSION

A low pressure trough is currently making its way through the Pacific Northwest with the central axis of the trough pushing eastward through central California. The change in these upper level dynamics is causing stronger winds to develop across the region, particularly in the lee side of area mountain ranges, including the Coastal Range and the Tehachapi Range. These stronger gusts will continue through early Sunday morning before beginning more benign during the daytime hours of Sunday. Northwesterly flow associated with the trough is expected to keep minimum relative humidity below 20 percent across much of the lower elevations through Monday, raising the potential for grass fires, especially when paired with the stronger winds.

A cooling trend will continue into next week due to the northwesterly flow mentioned above, with afternoon highs closer to season averages, but remaining in the mid to upper 80s. A warming trend will setup midweek across the area as the trough pushes further east into the central United States, causing subsidence and high pressure to build in due to stagnating air aloft. This will bring about the next best chance for widespread triple-digit heat across the San Joaquin Valley and Mojave Desert. Each of these locations has a 50 to 60 percent probability for afternoon highs to exceed 100 degrees both Thursday and Friday. Above-average temperatures are expected to continue into the following week due to strengthening of a high pressure ridge.

AVIATION

VFR conditions expected across the central California interior for the next 24 hours. However, expect northwest winds at 12-15 kts with gusts near 22 kts through 09Z Sunday at the TAF sites. Also, gusts to 40 kts over the Mojave Desert slopes in eastern Kern County will occur through 09Z Sunday.

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

Wind Advisory until 2 AM PDT Sunday for CAZ338. Lake Wind Advisory until 11 PM PDT this evening for CAZ300-301. Lake Wind Advisory until 2 AM PDT Sunday for CAZ332.