612
FXUS66 KSTO 041921
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1221 PM PDT Sat Jul 4 2026


.KEY MESSAGES...

 - Warmer and more seasonable temperatures today. Cooling trend
   Sunday-Tuesday, with warmer temperatures mid to late week.

 - 5-15% chance of isolated showers late tonight/early Sunday
   morning across the Valley and foothills. Nonzero chance for
   isolated dry thunderstorms over NE mountains Sunday
   afternoon/evening.

 - A slight 5-15% chance for isolated mountain thunderstorms
   continues Monday-Tuesday.


 &&


.DISCUSSION...
Clear and sunny conditions are being observed across Northern
California on this 4th of July. Upper-level ridging aloft will
yield warmer temperatures today with weaker onshore flow through
the Delta. Triple-digit heat is in the forecast for portions of
the northern Sacramento Valley today, with isolated areas of
Moderate HeatRisk. Elsewhere in the Valley, mid to upper 90s, with
Minor HeatRisk. Regardless of the HeatRisk, if you are planning
on any outdoor activities for Independence Day be sure to drink
plenty of water, apply sunscreen, and always wear a life jacket if
you are on area waterways!

For evening/night events, temperatures at 8PM PDT will be cooling
as the sun sets. Expect partly clear conditions with scattered
mid to high level clouds and pleasant temperatures. Please
remember to practice fire safety by adhering to local and state
burn bans, firework laws, properly discarding matches/cigarettes,
not driving over dry grass, and report any new fires to 9-1-1.

The biggest update over the last 24 hours has been the increased
potential for light Valley/foothill showers late tonight/early
Sunday morning as a swath of sub-tropical moisture moves in from
the south. Our current upper level pattern does not possess
adequate forcing necessary for thunderstorm development, meaning
these will likely stay mid to high-based showers. Additionally,
dry air at the lower levels may limit any measurable precipitation
at the surface. As this moisture pushes northward, there is the
nonzero chance for isolated wet/dry thunderstorms over the
northeastern mountains as a shortwave moves across northern
portions of California, however confidence remains low regarding
any thunderstorm development.

Sunday onward, broad troughing is expected to redevelop offshore
bringing cooler, below-normal temperatures to the region and
continued daily mountain thunderstorm chances over the Sierra
through Tuesday. Warmer temperatures are then expected heading
into the mid week period, as ridging builds and heights increase
aloft.

&&


.AVIATION...
VFR conditions are expected over the next 24 hours. Southwest to
west wind gusts 15 to 25 kts in the Delta and over the Sierra.
South to southwest winds in the Sacramento Valley (northwest in
the northern SJ Valley). Gusts from 10 to 20 kts from 22Z Saturday
to 08Z Sunday in the southern Sacramento and northern San Joaquin
Valleys, otherwise gusts less than 12 kts in the Valley. Slight
chance for light rain and virga Sunday morning south of Interstate
80 after 12z Sunday into the afternoon.


&&

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

&&

$$