textproduct: San Joaquin Valley

KEY MESSAGES

1. Low relative humidities in the lower elevations of Central California brings at least a moderate risk of Fire Danger through this weekend.

2. Warming trend continues until Saturday, with a lowering trend Sunday into next week.

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

DISCUSSION

Current high pressure ridging along the US west coast will provide the mechanism for temperatures to remain above average today and Saturday. Latest model guidance indicates a 60-80% probability for high temperatures above 95 degrees Fahrenheit across the San Joaquin Valley and Kern County desert, lowering to a 20-30% probability by Saturday.

Warm afternoon temperatures combined with diurnal northwesterly wind will bring a 10-15% probability for thunderstorms along the Sierra Crest today. Likewise, these thunderstorms are associated with a 10-20% probability for wetting rain along the highest point of the crest where orographic uplift is maximized.

An upper-level trough approaches from the Pacific Northwest by Tuesday and brings a low (20-30%) probability for measureable precipitation (at least 0.1") over the Sierra Nevada along with seasonal temperatures across the forecast area. Winds will increase over the typical prone areas, such as the Sierra Nevada crest and the Mojave Desert slopes. For now, the probability of a 40 mph gust in these areas is at 30-40% on Tuesday afternoon and evening. A warming trend soon follows by late next week, as high pressure returns to the region.

AVIATION

VFR conditions prevailing for the next 24 hours. High probability (>75%) for 15 kts northwest gusts prevailing across the San Joaquin Valley and eastern Kern County desert areas between 23Z 05/22 to 06Z 05/23.

FIRE WEATHER

Low minimum relative humidity (<20%) will continue across the forecast area through the weekend. Fast moving and developing grass and brush fires will be the main concern regarding available fuels. Winds will be diurnal in nature. Poor to moderate overnight humidity recovery.

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.