textproduct: San Joaquin Valley

UPDATE

Updated Aviation Section.

KEY MESSAGES

1. Fire Weather Watch in effect from late Friday night through early Monday evening for San Joaquin Valley and West Side Hills.

2. Wind Advisory in effect Friday evening through Sunday evening for the Indian Wells Valley, Mojave Desert, and Mojave Desert Slopes.

3. Lake Wind Advisory in effect Friday evening through Sunday evening for Kern River Valley, including Lake Isabella and Kernville.

4. Strong winds, increasing temperatures, and low relative humidities will create increased fire risk Today and this weekend.

5. A slight cooldown this weekend before warmer temperatures return next week.

6. Practice safety around area lakes, rivers, and streams, as waters are still running cold.

DISCUSSION

A brief warming trend tomorrow is expected to be followed up by a cooling trend this weekend, due to an incoming trough of the the CONUS. This will also lead to increased winds across our entire CWA, especially the Mojave Desert and the adjacent Slopes, and around Lake Isabella beginning 5pm tomorrow afternoon through Sunday evening. A Wind Advisory has been issued for these locations during that time period.

This trough will also cause the relative humidities for the San Joaquin Valley and the West Side Hills to fall below 20% from Friday into Monday, with elevated winds occurring at the same time. This will lead to an elevated fire risk for those regions, and a Fire Weather Watch was issued as a result. This will also likely be upgraded to a Red Flag Warning by tomorrow. This Watch is currently in place from late Friday night into Monday evening. And while the winds on Monday are expected to calm down compared to the weekend, the relative humidities are expected to drop further Monday afternoon as temperatures warm up through the week, with values below 15% for the Valley and Coastal Range from Monday into next Thursday. Fuels in those regions are forecast to become much drier as a result of these conditions, further increasing the fire risk.

Keep in mind that even though temperatures will continue to be above normal through the next week, rivers and streams will continue to run cold throughout the heat of the day, so practice water safety when using said places.

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

Wind Advisory from 5 PM Friday to 11 PM PDT Sunday for CAZ337>339. Fire Weather Watch from late Friday night through Monday evening for CAZ579-580. Lake Wind Advisory from 5 PM Friday to 11 PM PDT Sunday for CAZ332.