Oroville, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

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FXUS66 KHNX 172311
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
411 PM PDT Sun Aug 17 2025

.UPDATE...
Aviation section updated

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.KEY MESSAGES...
1. The cooling trend is expected to continue until Monday, and
both the Central Valley and Kern County desert will continue to
see a Minor Heat Risk through Tuesday.

2. A slight (10-20%) chance of afternoon and evening showers
and thunderstorms exists in the higher elevations of the Sierra
Nevada today. Otherwise, chances for isolated mountain and
desert thunderstorms are in store later this week.

3. A warming trend returns by the middle of the week with triple
digit heat in the warmest locations. The potential for Major
Heat Risk returns by Thursday in the Kern County desert and
enters into the Central Valley by Friday.

4. Elevated fire risk with minimum relative humidity expected
to be less than 10 percent in the Mojave Desert with breezy
winds in the afternoon to evening.

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.DISCUSSION...
Another mild day, at least for mid-August, is
expected today following a relatively cool morning. Highs will
remain in the 90`s at the warmest locations in our forecast area,
although a triple digit won`t be out of the question for the
Indian Wells Valley in northeastern Kern County. A dry southwest
flow and upper-level trough over the Pacific Northwest will
keep convection over the Sierra Nevada at bay, but it`s possible
that the high country of Yosemite NP might see a storm or two
this afternoon and evening. Things might become somewhat more
interesting later this week, but in the meantime, expect a
warming trend after Monday.

By Wednesday, widespread triple digit heat returns to the
desert, while triple digits return to the Central Valley by
Thursday. This is due to the ridge of high pressure retrograding
back to the West Coast states. Further heating will occur
Friday into next weekend, prompting a Major Heat Risk for both
the Central Valley and Kern County desert (which could begin as
early as Thursday in this particular region). There is some
uncertainty regarding the desert heat could be an influx of
monsoonal moisture which might mitigate some heating, although
there is a high probability (60-90 percent) of highs at least
105 degrees starting Thursday. At least for now, the past
couple of runs of the ensemble guidance has been creeping up the
temepratures for later in the week and next weekend. Many San
Joaquin Valley locations will potentially see the hottest
temperatures this year so far, and the chances for highs to
reach at least 105 degrees are a bit higher than during the
previous heat event (currently 30-60 percent as early as Day 6,
or Friday). There is also some uncertainty regarding how high
temperatures in the Central Valley will reach, including in our
northern zones. Based on the uncertainty and in consensus with
neighboring forecast offices, will hold off on issuing heat
products for now. For the time being, enjoy the break from the
heat.

The latest CPC (Climate Prediction Center) 6-10 temperature
outlook continues to favor above average temperatures at a 50 to
60 percent probability, while the 8-14 day outlook shows near
average temperatures. So, it does appear there could be some
relief from the heat by the end of the month.

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.AVIATION...
0Z Update:

VFR conditions are expected in the San Joaquin Valley for the next
24 hours. There is a slight, or 10-15 percent, chance of
mountain obscuring showers and thunderstorms over the higher
elevations of the Sierra Nevada, mainly towards Yosemite NP, through
03Z Monday.

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.AIR QUALITY ISSUES...
None.


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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...
None.
&&

$$

public...BSO
aviation....JPK

weather.gov/hanford