textproduct: San Joaquin Valley

KEY MESSAGES

1. The heat trend continues with temperatures about 10-15 degrees above average for the next several days.

2. Moderate to Major Heat Risk in the Central Valley through Wednesday. Heat Advisory has been extended further to 11 PM Wednesday.

3. Dry and calm conditions will persist for the week ahead.

DISCUSSION

The Heat Dome is back as a Heat Advisory now exist across Central California. Record to near record temperatures were observed this Saturday, with mid to upper 90s common across the San Joaquin Valley and triple-digit highs in select areas (e.g., Bakersfield reached 101 degrees just two degrees shy of its 2024 record). As a storm on the East Coast deepen, the Heat Dome will amplify, bringing even warmer temperatures on Sunday.

Probability of Exceedance (PoE) of reaching 100 degrees on Sunday exceeds 90 percent in the southwest corner of the San Joaquin Valley (Coalinga to Taft, including Bakersfield) and ranges from 40 to 80 percent along the Highway 99 corridor. Ensemble analysis places Sunday afternoons 90th percentile highs between 101 degrees (Merced) and 106 degrees (Bakersfield), making record-breaking temperatures likely across the southern valley.

By Monday, the heat dome will weaken slightly, with PoE values for 100 degrees dropping by 10 to 20 percent. Highs are expected to settle in the mid to upper 90s. A passing disturbance will offer only minor relief (a 2 to 3 degree drop at best) before the Heat Dome rebounds on Tuesday. Temperatures will remain steady in the mid to upper 90s across the valley for most of the week, with isolated triple digits in typical hot spots. High confidence remains for maintaining the Heat Advisory through much of next week.

A stronger storm approaching the West Coast late Friday into Saturday is expected to bring relief, lowering 90th percentile high temperatures back into more into the mid 90s. Ensemble model analysis also indicate potential precipitation over the Sierra Nevada near Yosemite on Friday and Saturday as the storm system passes across the district.

AVIATION

VFR conditions will prevail for the next 24 hours.

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

Heat Advisory until 11 PM PDT Wednesday for CAZ300>322.