textproduct: San Joaquin Valley

KEY MESSAGES

1. Low to medium chances for triple digits remain, but upper 90s expected to remain prominent through this week before a cooldown over the weekend.

2. Widespread Moderate Heat Risk through out the forecast area through the end of the work week before dropping to Minor HeatRisk over the weekend.

3. Heat Advisory has been extended until Friday at 10 PM.

DISCUSSION

Heat Dome expected to rebound as the hot temperatures across Central California continues. Confidence in another hot day in store for Wednesday is high as the Western States High Pressure is amplified in responses to a developing storm over the East Coast. Therefore, no relief from the heat until the weekend. Heat Advisory will therefore remain in place through Friday as heat hazards reside over the West.

Observational data showed the Todays High temperatures managed to reach their 75th percentile values. While the 90th percentile placed values well into the triple digit territory, upper 90s were more common. Therefore, as more ridging builds over the West, will continue to expect afternoon highs in the 75th to 90th percentile region (around 100 degrees).

Probability of Exceedance (PoE) of reaching 100 degrees on Wednesday, as the heat dome begins rebounding, will see a rise in percentage values. The change from Tuesday to Wednesday is about 10 to 15 percent net-positive gain. Therefore, Wednesday will have slight advantage toward hitting triple digits. While Thursday is showing minimal change in percentage values, Friday does show a drop toward having the San Joaquin Valley becoming dominated with highs in the mid to upper 90s.

Ensemble model analysis is showing some uncertainty with the strength of a disturbance during the weekend. While ensemble analysis does signal toward the development of a disturbance just how deep is still in question. Ensemble surface temperatures analysis is showing signs of of moving toward a cooler conditions direction and bringing relief to Central California. It is still a wait and see solution on the development of next weekend conditions.

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 10 PM PDT Friday for CAZ300>322.