textproduct: San Joaquin Valley

KEY MESSAGES

1. A warming trend continues through much of the week.

2. Minor Heat Risk expected for the lower elevations of Central California.

3. Areas of Moderate Heat Risk expanding across the San Joaquin Valley and Mojave Desert toward the middle of the Week.

4. Slight chance of showers and thunderstorms along the Sierra Nevada crest during the next few days.

5. Practice safety around lakes, rivers, and streams, as water is still running cold.

DISCUSSION

Temperatures to remain warm this week as a ridge becomes the dominant feature for the Central Valley. Today, temperatures will be widespread 90's throughout the Valley. There is a 90 percent chance of exceeding 91 degrees today for most Valley cities. There is also a 10 percent chance of exceeding 95 degrees for the Valley. Looking ahead, there is high confidence (75-90 percent)that the Valley will be in the 90 degree range for maximum temperatures through much of the week. As the ridge stays in place, the warmup will continue. Through the week, there is increasing probability to exceed 95 degrees. By Friday, the Probability of Exceedance (PoE) of reaching 95 degrees is 40-50 percent for the northern half of the San Joaquin Valley 60-70 percent for the southern half. The PoE of reaching 100 degrees is still low, with a 10-20 percent chance on Friday.

Part of the struggle to reach triple digit temperatures is a quick disturbance from a trough in Northern California. However, there will be minimal effects felt from it in Central California. The trough will cause a more zonal flow pattern, part of which will keep the CWA from being able to reach the 100's through the beginning of June. The ridge will take over once again towards the end of the week.

Humidity will lower this week as the temperatures rise. There is the possibility (5-10 percent) of some isolated thunderstorms over the Sierra Nevada Crest on Monday and Tuesday afternoon.The CPC currently has the Central Valley at Near Normal for both temperature and precipitation on the 6-10 day outlook. On the 8-14 day outlook, there is a 40-50 percent probability for above normal temperatures and leaning slightly below normal for precipitation in the 8-14 day outlook.

AVIATION

VFR conditions expected across the central California interior 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.