625
FXUS66 KSTO 301918
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1218 PM PDT Thu Jul 30 2026

For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.

.KEY MESSAGES...

 - Elevated Fire Weather Conditions in the northern Sacramento
   Valley and surrounding terrain, Burney Basin, and Sierra
   Foothills Friday through Monday due to hot temperatures, low
   humidities, and breezy winds.

 - Widespread Moderate HeatRisk Friday into next week across the
   Valley and Foothills. Hottest temperatures expected Saturday-
   Monday.

&&

.DISCUSSION...

Rest of today...

Another day of seasonable temperatures, dry weather, and light to
breezy onshore winds is on track for today across interior
NorCal. While building ridging aloft is expected to dominate much
of the weather pattern Friday into next week, split flow aloft
remains in place today as a punchy shortwave moves onshore near
the Oregon/California border. Despite the shortwave presence,
limited available moisture aloft and persistent dry surface
conditions will keep precipitation chances decidedly at 0 percent
for interior NorCal. Otherwise, winds will continue to follow
diurnal trends with a gradually increasing onshore push through
the afternoon and evening hours followed by lighter winds
overnight into Friday morning.

Friday into next week...

The late week into the weekend period will then see the large
scale ridge axis begin to center over the Desert Southwest and
Great Basin with rising heights aloft expanding to include
interior NorCal as well. This will result in a rapid warm up to
above normal temperatures and Moderate HeatRisk area wide through
the weekend and into next week. Current probabilities for high
temperatures greater than 100F sit around 60-90% for the Delta,
Valley, and lower foothills. Additionally, 50-80% probabilities of
high temperatures greater than 105F are forecast for the northern
Sacramento Valley Saturday-Tuesday.

A longwave trough ejecting from the Gulf of Alaska toward the
northern Pac NW over the weekend will present a slight wrinkle in
the weather pattern. While precipitation chances remain at 0
percent, periods of breezy north to west winds are expected to
develop at times across the northern Sacramento Valley and
surrounding terrain, Burney Basin, and northeast Sierra foothills.
Strongest winds gusting 15 to 25 mph are anticipated late
Saturday afternoon into midday Sunday and again Sunday evening
into midday Monday. The combination of low daytime humidity values
into the lower teens and upper single digits, limited overnight
humidity recovery, and periodically breezy winds will introduce
elevated fire weather conditions to the above areas Friday-Monday.
As the passing longwave trough flattens the ridge and introduces
broader reinforcing onshore flow to interior NorCal early to mid
next week, a slight cool down is anticipated, although widespread
Moderate HeatRisk is still expected to persist.

&&

.AVIATION...

VFR conditions are expected to prevail over the next 24 hours.
Winds generally remain 12 kts or less at TAF sites, although some
gusts nearing 18 kts will be possible through 06z Friday. Stronger
sustained winds up to 15 kts with gusts up to 22 kts are
otherwise expected through the Delta, gradually weakening after
12z Friday.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$