Marine Weather and Tide Forecast for Squaw Valley, CA

KEY MESSAGES
1. Elevated fire weather conditions will be present today along the West Side Hills and western San Joaquin Valley due to low relative humidity values and increased winds.

2. Above average temperatures return today and will warm through the week. Moderate Heat Risk is expected across the San Joaquin Valley on Wednesday.

3. There is a 50 to 80 percent chance for wind gusts greater than 50 mph in the Mojave Desert Slopes on Thursday.



DISCUSSION
An upper level trough that passed through central California over the weekend is continuing to progress eastward this morning, resulting in the prevailing flow over our region tracking out of the northwest. As the trough continues further eastward into the contiguous United States, a zonal pattern will set up over the West, with weaker winds aloft only approaching 20 to 25 knots. This zonal pattern normally results in temperatures near average; however, the decrease in winds aloft will create more stagnant conditions, and will result in temperatures a few degrees above average across the area. This pattern is especially prevalent on Wednesday, when afternoon highs are expected to approach ten degrees above normal. There is a 60 to 80 percent chance for temperatures to exceed 93 degrees across the San Joaquin Valley on Wednesday.

Recent ensemble runs show a series of two shortwave upper level troughs quickly passing through the Pacific Northwest region on Thursday and Friday, which will bring a cooling trend to central California as winds increase off the Pacific Ocean.
However, this being said, temperatures continue to be expected above normal.

While temperatures gradually increase through the rest of this week, dew point temperatures will hold steady or fall by a few degrees (depending on location). Current relative minimum relative humidity values hovering near 20 percent are expected to fall below 15 percent as temperatures increase on Wednesday and Thursday. These lower RH values create a more favorable environment for fire development in areas of fine fuels, such as grasses in the San Joaquin Valley. The addition of wind gusts near 20 miles per hour in the San Joaquin Valley resulting from the shortwave trough on Thursday give an increased risk for fire danger, as new fires may be able to spread more quickly.

Ensemble guidance isn’t too keen on a particular solution for next weekend, leading to some uncertainty for the conditions for the time frame. The most common solution is for a ridging pattern to build in, resulting in warming temperatures. This is also noted by the Climate Prediction Center which gives a 40 to 50 percent chance for above normal temperatures for our region in the 6 to 10 day period.


AVIATION
06Z Update There is a 60 to 80 percent chance for 30 mph wind gusts in the Mojave Desert Slopes through 12Z Tue. Otherwise, VFR conditions will prevail for the next 24 hours across the Central California Interior.

AIR QUALITY ISSUES
ISSUED: 05/19/2025 14:38 EXPIRES: 05/20/2025 23:59 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.