Marine Weather and Tide Forecast for Atwater, CA

KEY MESSAGES
1. Above average temperatures continue today, with a slight cool-off expected tomorrow and Saturday. Highs are expected to remain steady through the week, with a slight increase this Sunday.

2. Minimum relative humidity in the Valley is expected to be 15 to 20 percent in the afternoon, and wind gusts of 20 to 30 mph are expected later tonight, so a minor fire risk still exists today.

3. There is a 50 to 80 percent chance for wind gusts greater than 50 mph in the Mojave Desert Slopes on Thursday. A Wind Advisory has been issued for the area from 5 PM Thursday through 11 PM Friday.

DISCUSSION
A weak trough is expected to pass over Northern California today, with some downstream effects here in Central California in the form of elevated winds in the Valley and desert slopes.
There is a 50 to 80 percent chance for wind gusts greater than 50 mph on the slopes today, and wind gusts of 20 to 30 mph in the Valley later tonight. Coinciding with the winds are lowered RH's in much of the Valley this afternoon, with values of 15 to 20%.

As the trough passes through, temperatures are expected to cool slightly tomorrow and Saturday. With the exception of Sunday, where a ridge will quickly pass through and raise temperatures again, highs will be fairly steady through mid next week due to another weak trough passing through. Looking into the long term forecast, a strong ridge may build up by next Thursday, leading to an increase in temperatures throughout the region, though there is uncertainty here as a small trough could infiltrate the right and weaken the ridge.


AVIATION
18Z Update:

Gusty conditions are possible across the San Joaquin Valley, with a 20-30% chance for wind gusts greater than 25 knots after 18Z Thursday. There are more favorable chances in the Mojave Desert Slopes, with a 40-60% chance for 30 knot gusts through through 12Z. Otherwise, VFR conditions will prevail for the next 24 hours across the Central California Interior.

AIR QUALITY ISSUES
ISSUED: 05/21/2025 14:39 EXPIRES: 05/22/2025 23:59 None.

CERTAINTY

The level of certainty for days 1 and 2 is medium.
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 this afternoon to 11 PM PDT Friday for CAZ338.