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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS66 KMTR 211550
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
850 AM PDT Sun Apr 21 2024

...New UPDATE, MARINE...

.SYNOPSIS...
Issued at 205 AM PDT Sun Apr 21 2024

Warm inland temperatures expected throughout Monday before cooler,
unsettled weather returns Tuesday and continues through late week.
Light rain chances for Thursday night and into Friday.

&&

.UPDATE...
-- Changed Discussion --
Issued at 850 AM PDT Sun Apr 21 2024

Stratus coverage is much less widespread today than it was 24 hours
earlier. Yesterday, the marine layer was between 1200-1400 feet and
stratus was widespread through much of the Bay Area and Central
Coast. Today, the marine layer is closer to 1000 feet and patchy
stratus is confined to the coastline and near shore areas. Stratus
will continue to dissipate through mid-morning with sunshine and
warmer temperatures returning this afternoon.

High temperatures inland today will be, on average, 5-12 degrees
higher than average with highs in the upper 70`s to low 80`s.
Coastal high temperatures are near normal to slightly below normal
with highs in the upper 50`s to mid 60`s today. Given the time of
year and normal highs, there is a minor heat risk across inland
areas for populations sensitive to heat. Today will be the warmest
day for the next week with cooler temperatures and unsettled weather
returning Tuesday. Get outside today and enjoy the sunshine/warmer
weather while it lasts - just remember to wear sunscreen and bring
plenty of water!
-- End Changed Discussion --&&

.SHORT TERM...
(Today and tonight)
Issued at 205 AM PDT Sun Apr 21 2024

Once low clouds this morning dissipate across the San Francisco
Peninsula and Monterey Bay region, expect mostly sunny conditions
across the region. Far interior areas will warm this afternoon into
the low-to-mid 80s with temperatures tapering off to the lower 60s
near the coast. Tonight, mostly clear sky conditions are expected
with a few passing high clouds in advance of an approaching weather
system. Temperatures are only expected to cool into the low-to-mid
50s to upper 40s along the immediate coastline.

&&

.LONG TERM...
(Monday through Saturday)
Issued at 205 AM PDT Sun Apr 21 2024

Monday will be quite warm inland, only a few degrees cooler than
Sunday. However, a southerly surge is expected to spread northward
up the Big Sur coastline and reach the San Francisco Peninsula by
mid-to-late afternoon. Thus, coastal/favored upslope drizzle will
possible beginning Monday afternoon and continuing through Monday
night/Tuesday morning.

Tuesday will bring the return of unsettled conditions and cooler
temperatures regionwide as an mid/upper level low approaches
southern California. Afternoon high temperatures both Tuesday and
Wednesday will struggle to warm out of the upper 50s near the coast
and 60s inland. There is also a 10-20% chance of patchy coastal
drizzle Wednesday morning.

Thursday will be mostly dry, but chances are increasing for light
rain over the region Thursday night into Friday. This will be as
troughing persists over the region while a shortwave trough moves
inland. Temperatures on Friday will struggle to reach the 60s near
the coast and in the hills while interior areas stay in the 60s.
Drier conditions return Saturday but temperatures will be similarly
cool.

&&

.AVIATION...
(12Z TAFS)
Issued at 457 AM PDT Sun Apr 21 2024

VFR persists through the majority of the TAF period. Coastal stratus
development is minimal this morning, with only KSFO and KMRY
reporting clouds as small tendrils of stratus perforate the terminal
vicinity. Current winds are light, but are expected to increase
in the afternoon to become breezy and onshore. Westerly winds ease
into the night to become light. At this time, stratus does not
appear to impact many terminals in the early morning of Monday
with the exception of Monterey Bay. Though, just outside of the
TAF period, models do seem to indicate a southerly surge of
stratus, though it appears that these clouds should largely stay
confined to the immediate coast with a relatively shallow marine
layer. This will be something to watch closely in future TAF
issuances though, as any lift could permit stratus to overcome
portions of the coastal mountain barrier and push further inland,
especially through coastal gaps.


Vicinity of SFO...Satellite shows stratus hovering near the KSFO
terminal bringing SCT conditions. SFO likely to become BKN briefly
this morning, but returning to VFR after sunrise. VFR then lasts
through the remainder of the TAF period. Winds onshore and breezy to
moderate this afternoon, gusting to around 20 knots.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR conditions this morning are localized
to KMRY terminal. Stratus expected to begin to recede in the later
morning, ushering in VFR conditions as daytime heating begins. Winds
this afternoon out of the W/NW and generally around 10 knots. Winds
then ease into the late night to become light. Models have good
agreement as to stratus beginning to return and impact terminals
towards the end of the current TAF period as it pushes northwards
along the coastline.

&&

.MARINE...
-- Changed Discussion --
(Today through Friday)
Issued at 850 AM PDT Sun Apr 21 2024

Strong high pressure off the Northern California coast will
maintain northwesterly flow over the coastal waters through
Monday. Moderate to strong winds will impact the waters leading
to hazardous conditions. Winds will be strongest over the outer
waters north of Point Reyes. Winds ease and switch to southerly
starting Tuesday ahead of an approaching trough. Light southerly
swell continues to move through the waters this weekend and
through the upcoming work week.
-- End Changed Discussion --

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for Pigeon Pt
     to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory until 3 AM PDT Monday for Pt Pinos to Pt
     Piedras Blancas 0-10 nm.

     Gale Warning until 9 PM PDT this evening for Pt Arena to Pt
     Reyes 10-60 NM.

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...AC
MARINE...MM

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