Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 101611
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
911 AM PDT SAT OCT 10 2015
Mostly clear with above normal temperatures through midweek. High
clouds and locally breezy conditions over the higher elevations of
the Sierra this weekend. End of next week could see more clouds and
mountain showers as a weather system moves up from southern California.
Little change the next several days. No updates.
The state of CA has high pressure ridging across Central CA while
two low pressure systems flank that ridge to the northwest (Gulf
of Alaska) and to the south (off the coast of Baja California).
However, weather will stay dry for our CWA through middle of next
week. The ridge will weaken slightly this weekend as a pulse of
energy associated with the Gulf of Alaska low moves into the Pac
NW. This will help the Delta Breeze make a subtle return and will
cause some breezy conditions over the Sierra later this afternoon
into evening. This will make daytime highs over the weekend
slightly cooler than Friday, but values will remain slightly above
normal. The Fort Ord Profiler is showing a hint of a marine layer
early this morning, but it`s pretty shallow (around 500 ft thick).
The onshore gradient is forecast to be a moderate onshore flow
around 2-3 mb for the SFO-SAC gradient by early evening. Daytime
highs today will be in the mid to upper 80s for the valley, mid
70s to mid 80s through the Delta, and mid 60s to low 80s for
higher terrain which is approximately 5-10 degrees above average.
For Monday and Tuesday of next week, the high pressure ridging
across the state will re-strengthen. This warming trend will push
daytime highs up to 15 degrees above normal. Valley highs will
peak in the low 90s by Tuesday as dry conditions continue.
.Extended Discussion (Wednesday through Saturday)...
Middle of next week looks dry under an upper level high pressure
ridge over the western U.S. A closed upper low pressure system off
the Socal coast is forecast to continue drifting northward on
Wednesday and may begin to impact northern California towards the
end of the week. GFS remains the wetter model painting scattered
precipitation over Norcal on Thursday while the ECMWF which
remains a bit farther south indicates somewhat drier conditions.
With this weak low pushing into a strong ridge...believe ECMWF
probably has a better handle on this scenario and have weighed
more heavily on this model. For now...have kept any precip threat
confined to the Sierra Cascade range Thursday and Friday with just
a small drop in daytime temperatures. Longer range models are
hinting at a break down of the dominant western U.S ridge
beginning next weekend. At this time...any significant change
remains beyond the 7 day timeframe so first part of next weekend
VFR conditions all TAF sites next 24 hours. Increasing southwest
winds after 18z. Gusts up to 15 knots over valley but up to 40
knots over Sierra Nevada. Winds decreasing after about 06z Sunday.