000
FXUS66 KSTO 242133
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
233 PM PDT Fri Sep 24 2021

.SYNOPSIS...
A cooling trend is expected into early next week. High
temperatures in the 80s in the Valley this weekend are forecast to
dip into the 70s by Tuesday. Showers are possible over Northern
California late Monday into Tuesday with best chances over the
higher elevations north of I-80.

&&

.DISCUSSION...

Generally clear skies and dry conditions are being observed over
Northern California this afternoon aside from some haze due to
area wildfire smoke. Temperatures are running on the warm side
with widespread 90s across the Valley as of 2:00 pm this
afternoon. Some changes are expected for the forecast as a trough
off the Pacific Coast moves closer to the region. This will
initiate a cooling trend into early next week and will bring
unsettled weather to Northern California as it pushes inland.
Breezy onshore winds are expected to develop in the afternoon and
evenings this weekend ahead of the trough passage with gusts over
the higher terrain and Delta likely reaching 20 - 30 mph.
Possibly stronger, up to 35 mph in the Delta.

By Monday we are expecting unsettled weather to reach Northern
California with showers spreading over the Coast Range through
the day on Monday. By Monday evening and into the overnight hours
showers will continue to spread over much of the Northern
Sacramento Valley and Sierra. Precipitation amounts are expected
to be relatively light.

.EXTENDED DISCUSSION (Tuesday THROUGH Friday)...

The extended forecast period will start out with unsettled
weather across Northern California. Latest model guidance
indicates precip will be possible throughout the day, tapering
off by the evening. Areas that will see the best chances for
measurable rain will generally be north of I-80 over the Sierra
and southern Cascades. However, the central to northern Sacramento
Valley could see some light precip with this system as well.
Generally, this is looking to be a low impact event overall. Cloudy
skies and cooler temperatures will be also be widespread across
the region on Tuesday with highs expected to be 10 to 20 degrees
below average for this time of year. Thereafter, some breezy
northerly to easterly winds could develop behind the trough
passage as high pressure begins to build back in to the region.
Gusts around 15 to 20 mph are possible in the Valley and over the
Sierra and southern Cascades Tuesday into Wednesday. Temperatures
are expected to trend warmer into the later part of next week
with dry conditions expected to prevail.

&&

.AVIATION...

VFR conditions next 24 hours except for local MVFR/IFR conditions
vicinity Fawn Fire. Surface winds generally below 12 knots except
for gusts up to 25 kts possible through the Carquinez Strait and
Delta after 00Z Saturday.
&&

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

$$