311
FXUS66 KSTO 092114
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
214 PM PDT Sat Aug 9 2025


.DISCUSSION...

.SYNOPSIS...
Widespread Moderate HeatRisk continues into Monday with
widespread triple digit highs. Temperatures cool to near to
slightly below normal by midweek and trend a little lower by the
weekend. Dry weather continues.

&&

.KEY MESSAGES...

*Today-Sunday:
 - Gradual warming and drying trend continues in Sunday as desert
   Southwest and eastern Pacific ridging amplifies
 - Breezy north winds return again late tonight into early Sunday
   over portions of the northern and central Sacramento Valley as
   well as adjacent mountains and canyons
 - The northerly winds and low humidity will bring locally
   elevated fire weather concerns for the northern Sacramento
   Valley Sunday
 - A weak Delta breeze will bring slightly lower lows Sunday
   morning to influenced areas. Areas not influenced by the Delta
   breeze will have elevated low temperatures, especially in the
   foothills and northern Sacramento Valley, so continue to
   practice heat safety even at night tonight.
 - Warming trend peaks on Sunday with widespread Moderate
   HeatRisk, local Major HeatRisk and widespread triple digit high
   temperatures in the Valley.
 - Probability of high temperatures > 100F:
   --Northern Sacramento Valley: 90-100%
   --Remainder of the Valley: 40-90%

*Monday-Tuesday:
 - Temperatures remain hot on Monday with widespread Moderate
   HeatRisk and local Major HeatRisk across the Valley and
   foothills and into the mountains
 - Probability of high temperatures > 100F:
   --Northern Sacramento Valley: 80-100%
   --Remainder of the Valley: 35-75%
 - Onshore flow near the Delta will increase and give some relief
   with the Delta breeze for the Delta and southern Sacramento
   Valley, including the Sacramento metro area.
 - The East Pacific ridge axis aloft shifts westward by Tuesday,
   with shortwave troughing dropping down from western Canada
 - This will bring gradual cooling across interior NorCal with
   onshore flow bringing a more significant Delta breeze Monday
   evening and seasonable temperatures for Tuesday

*Wednesday to late Next Week:
 - Temperatures continue to trend lower mid to later week,
   slightly below average Wednesday and continuing to trend lower
   into the weekend
 - Periodically breezy onshore flow continues through the week
   into next weekend
 - Dry weather continues

.Changes from previous forecast...
- Little change.

&&

.AVIATION...
VFR conditions expected to prevail next 24 hours across interior
northern California. Sustained surface winds generally 12 kts or
less at TAF sites. West-southwest wind gusts 15-20 kts through the
Delta 00z-12z Sunday.


&&

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

$$