textproduct: San Joaquin Valley

KEY MESSAGES

1. Fire risk is of concern Friday through Sunday in eastern Kern and Tulare Counties.

2. Strong winds and gusts are expected through Sunday in the Tehachapi Mountains, Mojave Slopes, and Mojave Desert.

3. A warming trend is expected this weekend and into next week.

DISCUSSION

A low pressure system passing through the area has brought windy conditions, with gusts as high as 38 mph in the Valley this morning and above 60 mph in the Mountains. As the longwave trough continues east, a shortwave trough along its west side will evolve into a cutoff low over Baja California, where it will stall over the weekend. As this happens, the prevailing flow over the area will shift to the northeast, leading to a Mono wind event over the southern Sierra Nevada Mountains and high winds over the Tehachapi Mountains, Mojave Slopes, and Mojave Desert, including downslope acceleration and drying in these areas. The area east of Lake Isabella looks to be the focal point of this event, with a 35% chance of wind gusts exceeding 70 mph there Friday, increasing to 65% Saturday. 60 mph exceedance probabilities range from 35 to 80% along the Tehachapi and Sierra ranges in Kern and Tulare Counties Friday through Sunday. Wind products may include a High Wind Watch for the Mojave Desert and potentially into the Tehachapi Mountains along with a Wind Advisory in the Sierra Nevada Mountains.

Because of the strength of these winds and the resultant downslope drying, fire risk is of concern in the aforementioned areas, particularly in valley areas, with the hot-dry-windy index expected to reach the 90th to 95th percentile this weekend. While fuels are relatively moist, appropriate fire weather precautions should still be taken.

While the wind and low pressure will provide improved ventilation, abundant surface-level moisture will pose a minor fog risk (10% chance of visibilities below a quarter-mile) along the Highway 99 corridor in the Valley Friday morning.

As the low pressure clears the area, ridging is expected to build, allowing a warming trend through the weekend and early into next week, with Valley temperatures expected to reach the high 70s by Monday and possibly the mid-to-upper 80s by next weekend as the ridge continues to build.

AVIATION

VFR conditions prevail across the Valley. However, gusty winds to 30 kts in the nothern half of the Valley are expected through 07Z.

AIR QUALITY ISSUES

No air quality issues.

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.

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.