textproduct: San Joaquin Valley

KEY MESSAGES

1. A warm-up is expected to begin tomorrow and will continue through next week.

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

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

DISCUSSION

A warming trend begins today as a ridge begins to build over the southwest US. This will lead to high temperatures in the lower 90s across the Valley Sunday, increasing to the mid to upper 90s Monday, and flirting with triple digits by Tuesday. This will lead to widespread Moderate Heat Risk across the area through the week. Concurrent with the rising temperatures will be decreasing relative humidities. Minimum RH values of 20-25% across the Valley today and 10-15% in the desert, decreasing to 15-20% in the Valley and 8-12% in the desert to start the week. Although winds are not expected to be a major concern at the beginning of the week, the combination of increased temperatures and lower relative humidity will create elevated fire concerns, particularly in eastern Kern and Tulare Counties. There is a small (5-10%) chance the ridge could draw enough moisture into the upper Sierra Nevada to create a thunderstorm or two.

Clusters are in good agreement that a trough will approach the Pacific Northwest late Thursday into early Friday, which should moderate temperatures to near- or even slightly below-normal levels next weekend. Depending on the track and extent of the trough, this could simply lead to cooler temperatures, or it could lead to notably windier conditions, which, in turn, would lead to increased fire risk. Consequently, we will watch the evolution of the trough in the coming days.

AVIATION

VFR conditions expected across the area 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.