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

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000
FXUS66 KMTR 231139
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
439 AM PDT Sat Mar 23 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 1207 AM PDT Sat Mar 23 2024

Unsettled weather continues today into Sunday morning with breezy
winds, rain showers, and even a few thunderstorms. A bit drier for
Monday into Tuesday before rain chances return for mid week into
next weekend.

&&

.SHORT TERM...
(Today through Sunday)
Issued at 1207 AM PDT Sat Mar 23 2024

A vertically stacked low pressure system will drop southeast towards
the CA/OR border by this evening as the associated surface low
gradually fills. After a brief lull in precipitation for the Bay
Area early this morning expect an uptick in activity during the late
morning/early afternoon hours as a surface trough approaches
northern and central California from the west. Instability will be
on the increase during this time as mid-level lapse rates exceed
minus 7 degrees/km as colder air arrives aloft. Mixed layer CAPE
(convective available potential energy -- a value approximating the
robustness of a thunderstorm updraft should one develop) still
appears to peak around 200-300 J/kg this afternoon with only modest
largely unidirectional shear. This environment appears supportive of
isolated to perhaps scattered thunderstorms with lightning, locally
heavy rainfall, small hail, and gusty winds as the primary hazards.
Rain amounts will vary widely given the convective nature of showers
and storms with some folks seeing nothing while localized spots
under a heavy shower or storm could pick up a quick 1" or so. While
the large-scale environment appears unsupportive of widespread
flooding concerns, can`t rule out localized issues if a heavy shower
or storm overstays its welcome in an urban and/or hydrologically
sensitive area. Scattered showers and isolated thunderstorms are
likely to persist (with a bit less coverage) overnight into Sunday
morning, with the greatest potential shifting south towards the
Central Coast by early Sunday afternoon. Temperatures will be on the
cool side given increased cloud cover and onshore flow with highs
mostly in the 50s to around 60. Lows tonight will be mostly in the
40s.

&&

.LONG TERM...
(Monday through Friday)
Issued at 1207 AM PDT Sat Mar 23 2024

Generally quiet through the first portion of the week although a
weak weather system may bring small rain chances to the Bay Area
(generally north of the Golden Gate) on Monday.

Otherwise wet weather returns to the region on Wednesday into
Thursday as a weak cold front passes through the region. Rain
amounts at this point appear to be more beneficial than overly
impactful.

Another system with a better moisture tap looks to impact the region
on Friday into next weekend with another round of wet weather
anticipated.

&&

.AVIATION...
(12Z TAFS)
Issued at 430 AM PDT Sat Mar 23 2024

This TAF period`s main concern hazard/impact wise is the chance
for thunderstorms (30%). The overall trend for this TAF period is
for post-frontal rain showers to continue throughout the entirety
of today with a steadier, more organized push of rain to move
through the area towards the end of the 24-hour TAF period.
Flight categories are expected to remain marginal VFR through the
TAF period; however, brief periods of MVFR or IFR conditions are
possible with stronger showers.

Vicinity of SFO...Currently VFR with breezy southwesterly flow. The
main hazard this TAF period will be the chance (30%) for
thunderstorms mid-morning today into early-morning tomorrow. Post-
frontal rain showers will continue throughout the day with steadier,
more organized rain slated for early tomorrow morning with chances
diminishing towards the end of the TAF period.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently VFR at both terminals. The main
hazard this TAF period will be the chance (30%) for thunderstorms
mid-morning today into mid-morning tomorrow. Post-frontal rain
showers will continue throughout the day with steadier, more
organized rain slated for the end of the TAF period.

&&

.MARINE...
(Today through Thursday)
Issued at 430 AM PDT Sat Mar 23 2024

Increasing thunderstorm chances (30%) along with scattered post-
frontal rain showers will be present over the waters today
through Sunday morning. Fresh westerly breezes will give way to
strong northwesterly breezes by Sunday. Wave heights will build
through the weekend and begin to abate by the beginning of the
work week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 3 PM PDT Sunday
     for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt
     Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory from 3 PM this afternoon to 9 AM PDT Sunday
     for Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Gale Watch from Sunday morning through Sunday afternoon for Pt
     Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 3 PM PDT Sunday for Pt Arena to Pt
     Reyes 10-60 NM.

     Small Craft Advisory from 9 AM this morning to 3 PM PDT Sunday
     for Pigeon Pt to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...SPM
LONG TERM....SPM
AVIATION...Sarment
MARINE...Sarment

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