Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 151606

Area Forecast Discussion
National Weather Service Sacramento CA
906 AM PDT Wed Aug 15 2018

Dry with near normal temperatures through Thursday, then above
normal Friday through early next week. Smoke impacts from
wildfires continue.

Update: Temperatures are a couple degrees cooler than this time
yesterday morning due to increased onshore flow. Marine stratus
advected into the Valley for a couple hours this morning. Visible
satellite showing most of that stratus has dissipated. Radar
returns that were over eastern Shasta County this morning have
moved northeast and are expected to stay out of the forecast area
for the rest of the morning. A slight chance of isolated
thunderstorms still exists this afternoon and evening south of
Highway 50. HEC

.Previous Discussion...
Interior NorCal sandwiched between upper
troughing off the West Coast and high pressure over the Desert SW.
Monsoonal moisture continues to lift north through the CWA, and
88D showing some light returns over Eastern Shasta county attm.
Higher resolution models indicating moisture and threat of showers
will lift north of the CWA early this morning. Flow through the
Carquinez Strait has been strong overnight with marine layer about
2k ft deep. Expect some stratus will advect into the Delta area
this morning. Short wave trough approaches the West Coast today
with continued enhanced onshore flow. High temperatures forecast
to be near to slightly below normal.

Secondary upper trough approaches the NorCal coast Thursday and
moves through early Friday. Onshore flow forecast to weaken some
Thursday allowing for slight warming in Delta breeze influenced
areas. Little change in high temperatures expected elsewhere
across the CWA Thursday.

Heights rise Friday as shortwave upper ridging approaches, then
moves through Saturday. Warming expected over the forecast area
Fri/Sat with highs increasing to above normal. Widespread triple
digit max temperatures return to the Northern Sacramento Valley
Saturday with upper 90s elsewhere in the Central Valley.




Norcal will start out extended period under upper level southwest
flow between high pressure over the southwest U.S. and a weak
trough over the northeast Pacific. This stable pattern should keep
any showers or thunderstorms out of the forecast. Despite onshore
flow aloft. airmass will remain warm enough for daytime highs to
remain a few degrees above normal. A slight cooling takes place
early to mid next week as the weak system off the Pac NW coast
unsuccessfully tries to push inland. Even with the slight cooling
Monday and Tuesday, daytime highs remain a few degrees above
norms. Little change on Wednesday as Southwest U.S. ridge holds
strong. Kept haze in forecast across CWA through the extended
period as fires over norcal showing no signs of going away in the
near future.



Local MVFR/IFR conditions in HZ/FU near wildfires, otherwise VFR
continues over the area for the next 24 hours. Winds below 15
knots except Local SW surface wind gusts 25 to 30 kts vicinity of
the Delta. A slight chance of thunderstorms over the northern
Sierra crest south of U.S. 50. &&


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