Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

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000
FXUS66 KMTR 232350
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
450 PM PDT Tue Jul 23 2019

.SYNOPSIS...Inland temperatures will warm to above seasonal
averages through the remainder of the week and into the upcoming
weekend as high pressure dominates the weather pattern. The
influence of a shallow marine layer and persistent onshore flow
will keep conditions seasonably mild near the coast and allow
night and morning low clouds to persist.

&&

.DISCUSSION...as of 02:35 PM PDT Tuesday...The marine layer is
situated at around 1000-1200 ft AGL per the Fort Ord Profiler as
satellite imagery shows low clouds along the coast with mostly
clear skies inland. A mid/upper high continues to build over the
Desert Southwest while an upper low sits just offshore of western
Canada with an associated trough extending southward along the
west coast down to Northern California. The mid/upper high is
still circulating mid/upper level moisture across southern and
eastern California that is generating some high clouds over our
area today in addition to thunderstorms off to the east. Lightning
detection shows numerous strikes over the Sierra this afternoon.
Temperatures across the region today are around 5 degrees cooler
than this time yesterday as the aforementioned upper trough to the
northwest has acted to stall warming.

Expect temperatures to increase once again starting tomorrow and
continuing to rise throughout the rest of the week as the upper
ridge strengthens and builds westward towards California. Interior
locations will see the most significant warming as persistent
onshore flow and a shallow marine layer will keep temperatures at
the coast relatively mild. Additionally, expect night and morning
low clouds and patchy fog to continue throughout the week. Highs
over coastal areas will likely remain in the 70s while inland
locations see more widespread upper 80s and 90s. Isolated inland
spots will reach triple digits. This translates to roughly 10
degrees above seasonal averages over the interior. The ridge over
the Desert Southwest will advect monsoonal moisture over the
region late this week likely increasing mid/upper level clouds.
Today`s run of the NAM also shows an increase in mid to upper
level instability over the region Thursday night into Friday
morning in addition to the monsoon moisture. Right now, it looks
like the best chances of convection will be outside of our
forecast area. Will continue to monitor for any potential high-
based showers and/or thunderstorms.

Looking out into the weekend, both deterministic and ensemble
models continue to show the ridge of high pressure moving westward
over southern California. This will likely create additional
warming with afternoon highs above seasonal normals for much of
the district. In the longer term, both the CPC 6-10 day and 8-14
day temperature outlooks show above average temperatures
persisting over California.

&&

.AVIATION...as of 4:48 PM PDT Tuesday...The marine layer is
shallow at around 1000 feet. The northerly gradient is increasing
and models forecast it to increase even more tonight as surface
high pressure builds into the Pacific Northwest coast. As a result
stratus is expected to remain out of the SFO Bay Area tonight.

Vicinity of KSFO...VFR through Wednesday. West winds to 15 kt
gusting to 20 kt through 04Z.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...Satellite image shows stratus over the
southern half of MRY Bay which will spread into MRY and SNS after
01-02Z.

&&

.MARINE...as of 04:20 PM PDT Tuesday...Breezy northwest winds will
persist today across the coastal  waters. Winds will increase
becoming gusty tonight and Wednesday  as high pressure builds into
the Pacific Northwest and northern  California. Light southerly
swell coupled with short period wind  waves will continue through
the week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tngt...SCA...SF Bay until 9 PM
             SCA...Mry Bay until 9 PM
             SCA...Pigeon Pt to Pt Pinos 0-10 nm until 9 PM
             SCA...Pt Arena to Pigeon Pt 10-60 nm
             SCA...Pt Arena to Pt Reyes 0-10 nm
             SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
             SCA...Pt Reyes to Pigeon Pt 0-10 nm until 3 AM

&&

$$

PUBLIC FORECAST: AS
AVIATION: W Pi
MARINE: CW

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