textproduct: San Joaquin Valley

KEY MESSAGES

1. Cooler temperatures this weekend before a warmup to begin next week.

2. Hot and dry conditions next week will create increased fire risk across the region.

3. 15-25% probability for thunderstorms in the Sierra Nevada, including isolated risk for dry lightning.

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

DISCUSSION

A trough is sliding through California this weekend bringing slightly cooler temperatures and improvement in minimum RH values. However, the trough also brings some instability as there is a 15-25% probability for thunderstorms in the Sierra Nevada, including isolated risk for dry lightning especially around Yosemite.

After the trough slides out on Sunday, a ridge develops and will strengthen over the Desert Southwest bringing temperatures back up with a return of triple digits. However, the setup of this ridge could lead to the first monsoon surge of moisture. Latest NBM 12 hour thunderstorm probabilities highlight a 15 to 25 percent chance of thunderstorms over the Sierra Nevada on Wednesday afternoon and evening. In the long term, the CPC continues to highlight above average temperatures in both the 6-10 and 8-14 day outlooks.

AVIATION

VFR conditions expected across the area for the next 24 hours. 15-25% probability for thunderstorms across the Sierra Crest this afternoon, particularly for the central Sierra and around Yosemite National Park.

FIRE WEATHER

Elevated Fire risk today along the edge of the Sierra Crest and the Mojave Desert. RHs will improve through the weekend before decreasing to begin next week.

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.