Oroville, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

138
FXUS66 KHNX 181853 AAA
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
1053 AM PST Thu Dec 18 2025


.UPDATE...Updated Key Messages.

&&

.KEY MESSAGES...

1. Low clouds and dense fog return to the San Joaquin Valley and
Sierra foothills later tonight into Friday morning.

2. A significant pattern change is expected to take place by this
weekend with precipitation likely for the Sierra Nevada and its
foothills from Fresno County northwards. Moderate to briefly heavy
precipitation is possible in these areas from Saturday evening into
Sunday.

3. A second, stronger system is expected to arrive Tuesday, with a
moderate risk for heavy precipitation throughout Central California,
and a high risk for heavy snow in the Sierra Nevada expected from
Christmas Eve through the 26th next week.


&&

.DISCUSSION...
Low clouds and fog persist this morning; some clearing will
occur once again by this afternoon. In addition, there have been
reports of dense fog over the passes in Kern County near 4,000
feet, including Tehachapi along Highway 58 and the Grapevine
along Interstate 5 near the summit of Tejon Pass. Expect fog
and low clouds to redevelop at least over the Central Valley later
tonight, while there is up to a 40 percent chance of dense fog
returning after midnight tonight.

A chance of precipitation exists for Fresno County northward
beginning Friday afternoon, with the highest chances towards our
northernmost portions, including Merced County to Yosemite NP
(60-70 percent) but lower chances southward. Additional chances
continue into Saturday and Sunday, with the best chances in our
northern portions. A slight (at least a 15-20%) chance for
precipitation exists a bit south by Sunday, but mainly north of
Kern County. Precipitation amounts will be light to moderate,
with the highest amounts projected near Yosemite for this
weekend.

More widespread precipitation is in store for next week,
including Tuesday until at least Christmas Day. Confidence
continues to increase for totals of at least two inches of
rainfall in the San Joaquin Valley and several inches for the
Sierra Nevada foothills for this period. Snow levels will be
above 8,000 feet until at least Monday and lower to about 7,000
feet for Tuesday onward. Exact timing of precipitation for next
week remains uncertain, but it appears we are in for an active
period for quite some time once it begins.

An extended period of above average precipitation continues,
based on latest information from the Climate Prediction Center.
The 6-10 day outlooks show about a 70-80 percent chance for
above average precipitation, and the latest 8-14 day outlook has
a 50-60 percent chance for much of our forecast area. Above
average temperatures are favored for the 6-10 day period (about
a 35-50 percent chance) and up to a 40 percent chance for the
8-14 day period.

&&


.AVIATION...
IFR to LIFR ceilings and visibilities are expected to prevail for
much of the San Joaquin Valley during the next 24 hours, with a
30 to 40 percent chance of VLIFR in dense fog from 09Z to 18Z
Friday. IFR to LIFR conditions will also persist in the coastal
ranges, Sierra foothills, and the Kern County mountains due to
low clouds. Otherwise, VFR conditions will prevail in the Sierra
Nevada and in the Kern County mountain and desert areas over
the next 24 hours.

&&

.AIR QUALITY ISSUES...
On Thursday December 18 2025, Fireplace/Wood Stove Burning
Status is: No Burning Unless Registered in Fresno, Kern, Madera,
and Merced Counties. Burning Discouraged in Kings, Tulare Counties,
and Kern (Greater Frazier Park Area) and Sequoia National Park and
Forest.


&&

.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...
None.
&&

$$

BSO

weather.gov/hanford