textproduct: San Joaquin Valley

KEY MESSAGES

1. Wind Advisory for the San Joaquin Valley from 7 PM Saturday to 5 AM Sunday. Wind Advisory from 10 PM Saturday to 11 AM Sunday for the Mojave SLopes and Desert. Lake Wind Advisory from 1 PM Saturday to 10 AM Sunday for San Luis Reservoir. Lake Wind Advisory from noon Saturday to 11 PM Sunday for Lake Isabella.

2. Minimum relative humidity between 15-30 percent and high confidence for 30 mph wind gusts lead to Elevated Fire Risk for the Valley and Foothills Saturday night through Sunday morning.

3. Minor Heat Risk over the weekend into next week with a cooling trend this weekend. Although much cooler, high confidence that temperatures will be above normal.

DISCUSSION

While clear skies and calm conditions are expected for most of today, a quick-moving low pressure system approaching the CA/OR border will come onto land later this afternoon. This will cause elevated wind gusts through Sunday morning, with high confidence (a 70-100 percent probability) for gusts of 30 mph or higher across the central San Joaquin Valley and 45 MPH along the Mojave Slopes and High Sierra of Madera County.

As a result, numerous Wind Advisories have been issued for Saturday evening and Sunday morning. This includes Lake Wind Advisories for Lake Isabella and San Luis Reservoir into Sunday, with gusty winds expected to continue across the Kern River Valley into the evening hours. As of the latest High Resolution Ensemble Forecast (HREF) model run this morning, valley wind gusts will particularly be concentrated along Highway 99 and 41 between Delano and Merced. Meanwhile, especially gusty winds in the Mojave Desert will primarily impact the Mojave Slopes west of Highway 14. As these elevated wind gusts will begin during the late afternoon, a brief overlap with relative humidity values in the teens and twenties brings moderate fire weather risk, though overnight recovery and sub- critical fuel moisture will limit risk overnight and Sunday morning.

Following the departure of the low pressure system into the Great Basin, a cold front crossing over California on Sunday will drop temperatures across the area by 5-10 degrees, with mid-to-upper 80s in the San Joaquin Valley and low-to-mid 90s in the Mojave Desert. Only minor risk for heat illness is expected this weekend and early next week. Longer-term modeling indicates a return to above average temperatures at the end of next week as a ridge of high pressure builds over California.

AVIATION

VFR conditions expected to continue for the next 24 hours. High confidence (greater than 70 percent probability) for northwest gusts of 25-30 knots across the central San Joaquin Valley (including KMCE, KFAT, and KVIS) from 2 to 12Z Sunday, with a 35-40% probability of gusts exceeding 30 knots. West gusts of 35-40 kts affecting the Mojave Slopes (including KMHV) from 5 to 18Z Sunday.

FIRE WEATHER

A low pressure system crossing over the CA/OR border will bring gusty winds to the central San Joaquin Valley and Sierra Nevada crest of Madera County late Saturday afternoon. Gusts of 30 and 45 mph respectively will overlap with relative humidity around 20 to 30 percent before evening recovery begins. While both minimum relative humidity and fuel curing are not at critical levels, there is moderate fire weather concerns through Sunday morning as strong winds will support rapid initial spread of any fire starts.

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 from 10 PM this evening to 11 AM PDT Sunday for CAZ338.

Lake Wind Advisory from 1 PM this afternoon to 10 AM PDT Sunday for CAZ300.

Wind Advisory from 7 PM this evening to 5 AM PDT Sunday for CAZ301>307-309>312-315.

Lake Wind Advisory until 11 PM PDT Sunday for CAZ332.