Summit, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

316
FXUS66 KHNX 171143
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
343 AM PST Wed Dec 17 2025

.UPDATE...
Aviation section updated.

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.KEY MESSAGES...
1. Fog, while dense at times, and low clouds will continue each
night and morning across the San Joaquin Valley into the
foothills up to 1,500 feet through at least Friday. A light
drizzle is also expected each morning with the fog and stratus.

2. Above average temperatures will continue across the
mountains and desert until Tuesday, with a cooling trend
expected as the high pressure weakens over Central California.

3. A significant pattern change is expected to take place by
this weekend with precipitation likely for the Sierra Nevada and
its foothills through at least next week.

&&

.DISCUSSION...
The consistent stable pattern over the southwest will continue
through at least the beginning of next week, with strong ridging
keeping the low stratus clouds in place for the center of the
San Joaquin Valley with dense fog on the edge of the Valley from
elevations of 500 feet to 1500 feet. This stratus will also
lower further down during the nighttime hours and lead to fog in
the Valley itself.

A small pattern change is likely in store for Central
California, with the ridging over the Southwest weakening
somewhat as a small trough passes through the Pacific Northwest.
This weaking may lead to slight troughing in Northern California
into Central California, which may lead to a small amount of
precipitation for the northern-most Counties in our CWA, mainly
in Mariposa County and Yosemite Nation Park. This small
disturbance may cause strong winds along the Sierra Nevada
peaks and down into the Mojave Desert. It may also provide
elevated winds aloft to break the inversion over the Valley and
lead to the stratus deck clearing out, though it`s unclear if
those winds will be strong enough.

Confidence has increased for a more significant pattern change
for Central California this weekend into next week, with the
ensemble models consistently showing a large trough moving
through the west coast by this Saturday through the 26th of
December. The Climate Prediction Center has also highlighted
the 23rd of December through the 26th for a high risk (>60%) of
heavy snow in the Sierra Nevada, and moderate risk (40-60%) of
heavy precipitation for the majority of our CWA for the same
time 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 40
to 50 percent chance of VLIFR in dense fog between 12Z and 19Z
Wednesday. 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...
ISSUED:  12/15/2025 15:26
EXPIRES: 12/16/2025 23:59

On Tuesday December 16 2025, Fireplace/Wood Stove Burning
Status is: No Burning Unless Registered in Fresno, Kern, and
Madera Counties, and Kern (Greater Frazier Park Area). Burning
Discouraged in Kings, Merced, and Tulare Counties, and Sequoia
National Park and Forest.



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.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 until 4 AM PST Thursday for CAZ337>339.
Dense Fog Advisory until 11 AM PST this morning for CAZ314-316.
&&

$$

public...EW
aviation....McCoy

weather.gov/hanford