textproduct: San Joaquin Valley

KEY MESSAGES

1. Minor Heat Risk through Wednesday as temperatures remain around seasonal normal values.

2. Warmer temperatures dominate Thursday with a 30-50% chance of triple digits and a greater than 70% chance of Moderate Heat Risk throughout the Valley.

DISCUSSION

Weak Ridging moving through the West Coast ahead of a trough expected later this week. In the meanwhile, the interaction of the two features will allow for a good surge of southerly air into California. This surge will result in the warming of temperatures Today and Thursday. 24 hour change in temperatures is noting a rise of 3 to 6 degrees from this time on Tuesday. With afternoon highs reaching the upper 80s on Tuesday, this change will allow max temperatures to push into lower to mid 90s this afternoon. While the next trough will introduce cooler temperatures, precipitation may be limited as any subtropical moisture surges will remain well south and east of Central California.

A closer look at temperatures has the Probability of Exceedance (PoE) of reaching 100 degrees below 50 percent for the next several days from Today through Friday. Yet, PoE of reaching 95 degrees rises well above 70 to 90 percent (especially on Thursday) before conditions cool-down this weekend. Furthermore, ensemble 90th percentile range is showing widespread 98 to 100 degrees across the San Joaquin Valley on Thursday. This is a downward trend from 90th percentile values earlier in the week for the same time frame. Therefore, confidence in Triple digit heat is decreasing as the hot day will result in near triple digit heat.

Long Term analysis is showing the passage of the trough early next week with weak ridging returning toward the middle of the week. Climate Prediction Center is indicating a return of the warmer temperatures with less confidence in their precipitation analysis. Currently, both 6 to 10 Day and 8 to 14 Day precipitation outlooks shows near normal going out 14 Days. Therefore, will see a roller coaster ride in temperatures over the period with dry conditions during the same time period.

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

None.