textproduct: San Joaquin Valley

UPDATE

Updated Aviation Section.

KEY MESSAGES

1. Heat Advisory in effect for the majority of the area until 11 PM Saturday.

2. Widespread Moderate Heat Risk, including triple-digit heat, in the lower elevations Thursday until next weekend.

3. Hot and dry conditions will create increased fire risk in eastern Kern and Tulare Counties this weekend.

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

DISCUSSION

Triple digit heat has arrived to some locations in the San Joaquin Valley for the first time this year. More triple digits are in store Friday and Saturday. The chance for a high of at least 100 degrees is 70-80 percent in the SJ Valley and 80-90 percent in the Kern County portion of the Mojave Desert. The chance for a high of at least 105 degrees is near 30 percent in the desert, mainly towards the Indian Wells Valley. Expect mainly moderate heat impacts (Heat Risk) with this round of hot weather. Temperatures this hot are common in these areas during this time of year, although can feel quite hot to those who are not used to it. Also, these temperatures can adversely impact the sensitive groups, especially if precautions are not taken. Overnight lows will cool to the 60s in most locations, but remain near 70 degrees in some of the warmest locations, such as Bakersfield and Fresno.

For Sunday through midweek, we are still looking at widespread Moderate Heat Risk and similar temperatures, including more triple digits. Lower temperatures arrive later next week as a trough of low pressure passes over the Pacific Northwest and weakens the persistent ridge of high pressure. For now, forecast temperatures lower back to the 90s at the warmest locations on Thursday and next Friday. Dry conditions will prevail, except for a slight (10-15 percent) chance of isolated afternoon thunderstorms along the Sierra crest through this weekend. Low daytime humidity (8-18 percent throughout the SJ Valley and Kern County desert) will persist until midweek. Generally light winds will occur through the period, but we will have to monitor for some increase in speeds as we head into late next week. Confidence is increasing that we will see gusty winds in the typical prone areas, such as the West Side Hills and Kern County desert.

Aviation

VFR conditions expected in the San Joaquin Valley 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 Saturday for CAZ300>321-332.