textproduct: San Joaquin Valley

UPDATE

KEY MESSAGES

1. Wind Advisory in effect 11 PM Monday to 11 AM Wednesday for Indian Wells Valley, Mojave Desert Slopes, and Mojave Desert.

2. Lake Wind Advisory in effect 5 PM Monday to 5 PM Wednesday for Kern River Valley, including Lake Isabella.

3. Dry conditions will allow the fire weather risk to remain in place through the weekend and into next week.

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

5. Omega Block pattern will keep temperatures pleasant but allow for dry lightning chances in the Sierra Nevada for the next several days.

DISCUSSION

A Wind Advisory is in effect 11 PM Monday to 11 AM Wednesday for Indian Wells Valley, Mojave Desert Slopes, and Mojave Desert for southwest winds of 25 to 35 mph with gusts to 50 mph. A Lake Wind Advisory is in effect 5 PM Monday to 5 PM Wednesday for Kern River Valley, including Lake Isabella for west winds of 25 to 35 mph with gusts to 50 mph.

Warm conditions today, with high temperatures in the upper 80s to low 90s across the Valley. Moisture-wise, conditions have improved a bit, with minimum relative humidities expected to be around 20-25% across the Valley today. Similar conditions are expected tomorrow. There is a 5-10% chance of lightning in the Sierra foothills today, increasing to 15-20% in the middle elevations and 20-25% near the crest. There is a 10-20% chance of gusts exceeding 40 mph along the Mojave Desert Slopes overnight tonight.

Looking ahead, an Omega Block pattern is setting up across the country. As that happens, a low pressure will move southward down the west coast and stall out over the area. This will moderate temperatures, keeping highs in the upper 70s to upper 80s as it arrives on Tuesday. However, this will also bring broadly northerly flow, which will draw very dry continental polar air southward into the area. This will create anomalously dry conditions as we move into the mid-week. When we also consider the increased wind and the threat of lightning, some dry, the fire risk will increase substantially across the week, particularly Monday, Tuesday, and Wednesday. The risk will be most concentrated in eastern Tulare and Kern Counties, though all areas should be wary given abnormally dry fuels and abnormally high energy release components across the entire area. There is a 40-70% chance of gusts exceeding 40 mph along the Mojave Slopes and northern Sierra Crest overnight Monday and a 30-70% chance of gusts exceeding 55 mph along the entire Crest and the Mojave Slopes throughout all of Tuesday.

Despite warmer temperatures, lakes, rivers, and streams are still running quite cold. Practice cold water safety at all times. Even the most experienced swimmers can quickly and unexpectedly lose dexterity in cold water.

AVIATION

VFR conditions prevailing across interior central California for the next 24 hours.

AIR QUALITY ISSUES

Elevated PM2.5 and moderate-high ozone concentrations will create conditions unhealthy for sensitive groups this afternoon and evening. Take appropriate precautions.

CERTAINTY

The level of certainty for days 1 and 2 is high. The level of certainty for days 3 through 7 is high.

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 11 PM Monday to 11 AM PDT Wednesday for CAZ337>339. Lake Wind Advisory from 5 PM Monday to 5 PM PDT Wednesday for CAZ332.