Vallejo, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

706
FXUS66 KSTO 291922
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1222 PM PDT Mon Jun 29 2026

.KEY MESSAGES...

 - Elevated fire weather conditions today due to north winds and
   low daytime RH. Area of concern along and west of the I-5
   corridor in the Sacramento Valley.

 - Chances for isolated mountain thunderstorms this
   afternoon/evening; best chances south of I-80.

 - Cooler temperatures and breezy onshore flow expected Tuesday
   onward.

&&

.DISCUSSION...
An upper level low is positioned directly over interior NorCal
this afternoon. Most of the Valley is still experiencing north
winds at the time of this writing, with Red Bluff AP observing a
gust of 26 kts. North winds expected to continue through the rest
of the morning into the early afternoon. Positioning of low will
allow some forcing/lift along the Sierra crest this afternoon,
where a slight chance (10-15%) of a thunderstorm is possible. The
best chances will remain mainly south of I-80. Low is forecast to
dig further south then east tomorrow, prompting slight
enhancement of onshore flow and lowering of high temperatures.

NorCal looks to retain some upper level troughing influence as we
move through the middle of the week. High temperatures will remain
slightly below late-June early July normals through Thursday. By
the weekend, upper level troughing breaks down slightly as high
pressure builds in the Pacific and in the desert southwest. High
temperatures will respond by returning to normals Friday and
through the July 4th Holiday weekend. Triple digit highs are in
the forecast for the northern Sacramento Valley on July 4th,
however with the relatively cooler temperatures we have
experienced lately and overnight lows in the upper 50s to mid 60s
will keep Minor HeatRisk in the forecast the next 7 days.

&&

.AVIATION...

VFR conditions are expected over the next 24 hours. There is a
10-15% chance for isolated mountain thunderstorms south of I-80 in
the Sierra this afternoon/evening which may lead to isolated
MVFR/IFR conditions. North winds with gusts 15 to 25 kts in the
northern/central Sac Valley until 00Z Tuesday. West-southwest
gusts 15 to 20 kts in the Delta from 23Z Monday through 18Z
Tuesday.

&&

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

$$