textproduct: San Joaquin Valley

KEY MESSAGES

1. Extreme Heat will continue to be the major weather concern over the coming week. Extreme Heat Warnings and Heat Advisories have been extended through the upcoming weekend to account for this.

2. Persistent hot and dry conditions will also continue to promote the potential for wildfires with cured fuels.

DISCUSSION

The ridge of high pressure continues to sit over the West coast, bringing about dangerously hot conditions. The ridge is stagnant, unwilling to move and provide any relief to the Central Valley. Tomorrow, the Probability of Exceedance (PoE) of reaching 106 degrees is 20-30% for Madera and Fresno and Bakersfield. There is a 80-90% PoE of 102 degrees for those same cities. Therefore, temperatures can range from 102-106 degrees for the most metropolitan areas of the San Joaquin Valley. The PoE of 110 for the Mojave Desert is up to 55% in the hottest parts of the desert. Temperatures will continue to tick upwards into the weekend. That, combined with warm overnight temperatures providing little relief, as well as Major to Extreme HeatRisk has prompted the Extreme Heat Warning and the Heat Advisory to be extended out to Sunday. Continue to exercise caution regarding outdoor plans. Drink plenty of fluids, and ensure that pets and livestock have access to cold water and shade during the hottest parts of the day.

As expected with these hot temperatures, dry conditions continue to persist. The Mojave Desert continues to have relative humidities in the single digits, while the San Joaquin Valley will see relative humidity between 15-25% through Sunday. Light winds are expected, which will limit rapid fire spread. By Saturday, there is a 10-15% chance of thunderstorms in the Sierra Nevada mountains.

Looking into the long term, the CPC's 6-10 day outlook has most of the San Joaquin Valley in the 50-60% chance of above normal temperatures. By the 8-14 day outlook, there is a 33-40% chance of above normal temperatures.

AVIATION

VFR conditions will prevail for the next 24 hours with light northwest winds during the day and variable winds overnight.

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

Extreme Heat Warning until 8 PM PDT Sunday for CAZ337>339. Heat Advisory until 8 PM PDT Sunday for CAZ301>317-319-321-332- 334>336.