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

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156
FXUS66 KMTR 141725
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1025 AM PDT Sun Jul 14 2024

...New AVIATION...

.SYNOPSIS...
Issued at 911 AM PDT Sun Jul 14 2024
Between the deepening marine layer and the upper level
disturbance moving through the region, cooler conditions will
prevail across the region today, with near to below normal
temperatures continuing through the majority of the week. Expect
low clouds and fog to be possible each night and through the
morning hours, especially along the coast.

&&

.UPDATE...
Issued at 911 AM PDT Sun Jul 14 2024

Water vapor imagery shows an upper level disturbance lifting over
Northern California this morning, which will continue to bring the
threat of showers and thunderstorms, mainly to our north and east
today. Visible imagery shows a nice cloud shield with the
disturbance mainly to our north and east, along with some
thunderstorms already ongoing over the Sierra. In the meantime,
visible imagery also shows the marine layer pushed well inland
this morning. The Fort Ord shows the marine layer has deepened to
around 2000 feet this morning, and as such, we have seen some
drizzle along the immediate coast. In fact, a couple of sites have
picked up a hundredth. Will do a quick update to temperatures this
morning, given that the marine push should keep even our hottest
spots below the triple digit mark today. There is an outside
chance, albeit extremely small, that we could see a lightning
strike or two in North Bay today, but overall, not impressed at
the elevated instability. Palmer

&&

.SHORT TERM...
(Today and tonight)
Issued at 211 AM PDT Sun Jul 14 2024

Elevated light showers along an arm of weak baroclinic instability
aloft can be seen offshore of Sonoma County moving north as of 2AM
PDT. A stout inversion remains in place, especially along the coast,
with very warm dry air above the marine boundary layer up to H70.
Steep lapse rates from H70 to H50 are helping to drive what little
shower activity is possible over our area attm, otherwise any
shallow convection is unlikely through the remainder of the
overnight hours into later this morning. Temperatures will continue
their gradual cool down today with most locations farther inland
that have seen triple digit heat the past week or more, dropping
into the 90s providing some welcomed relief. The marine layer will
expand farther inland today and tomorrow, helping to cool
temperatures even further for locations in proximity to coast.
Interior locations away from the marine layer influence will see
highs mostly in the upper 70s and 80s today and Monday.

&&

.LONG TERM...
(Monday through Saturday)
Issued at 211 AM PDT Sun Jul 14 2024

The persistent dome of high pressure over the Four Corners region
begins to steadily amplify towards the Pacific Northwest tomorrow
into Tuesday before the ridge axis begins to pivot to the east.
Persistent troughing on the western periphery of the ridge across
northern and central California will help keep cooler temperatures
aloft over our area and surface temperatures right around normal for
this time of year through at least midweek. Extended guidance has
strengthened a disturbance to help breakdown the ridging later
this week, which has slowed the progress of increasing daytime
highs for the end of the week into next weekend.

&&

.AVIATION...
(18Z TAFS)
Issued at 1024 AM PDT Sun Jul 14 2024

Stratus continues to cover much of the area terminals this morning,
but is expected to clear towards noon to lead to widespread VFR
conditions. Breezy NW winds will return in the afternoon today for
most terminals. Stratus will make an early return in the evening,
bringing MVFR/IFR conditions, and winds will ease to become light.
Confidence on CIGS lowering to LIFR conditions in the overnight
hours tonight is currently very low given troughing and the
associated lifting influence. Highest confidence is in CIGs
maintaining at IFR altitudes through the night. Stratus then
clears in the late morning of Monday.

Vicinity of SFO...VFR through the early evening today, though
stratus will begin to filter in towards the 00Z hour bringing a few
low clouds over the terminal. Winds onshore and moderate in the
afternoon, later easing to become light in the night. MVFR CIGs
develop towards the late night and then last through the morning of
Monday.

SFO Bridge Approach...Stratus and low clouds will fill into the Bay
overnight with predominantly MVFR CIGs.

Monterey Bay Terminals...Stratus expected to clear towards noon
today to usher in VFR conditions. However, VFR will be short lived,
as coastal clouds are expected to make a return in the early evening
today. IFR CIGs last through the night, and may lower, though
confidence on becoming LIFR is very low. Clearing on Monday late in
the TAF period.

&&

.MARINE...
(Today through Friday)
Issued at 437 AM PDT Sun Jul 14 2024

Slight chances of light rain and drizzle will persist through the
weekend over the waters. Light to moderate northerly winds
continue through the afternoon today but begin to turn more
southerly starting Sunday. These light southerly winds are
expected to continue through the middle part of next week, but
then turn to become more northwesterly beyond then.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&

$$

SHORT TERM...JM
LONG TERM....JM
AVIATION...AC
MARINE...AC

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