273
FXUS66 KMTR 181811
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1111 AM PDT Sat May 18 2024

...New AVIATION...

.SYNOPSIS...
Issued at 300 AM PDT Sat May 18 2024

Quiet weather persists. Stratus coverage expected to dissipate by
mid-to-late morning with clearer, sunnier conditions expected
during the afternoon. Temperatures cool down slightly Saturday
before a weak warming trend begins Sunday. For coastal areas,
stratus will return during the evening hours but shouldn`t extend
too far inland.

&&

.UPDATE...
Issued at 854 AM PDT Sat May 18 2024

Low clouds spread well inland into the region`s valleys overnight
and persist this morning. They even made it into the North Bay!
These low clouds will retreat to the coast by late morning or early
afternoon. However, many coastal locations will remain in the clouds
throughout a good portion of the day and may only see the sun for
brief periods of time. That said, have lowered forecasted high
temperatures by a few degrees for the day as a weak, dry frontal
boundary moves across the region.

&&

.SHORT TERM...
(Today and tonight)
Issued at 300 AM PDT Sat May 18 2024

Stratus coverage is increasing over the Central Coast, North Bay,
and portions of the rest of the Bay Area. Inland stratus coverage is
a little patchier tonight than last night with the lowest clouds
staying closer to the coast. Friday`s high temperatures were limited
in areas where widespread stratus lingered through the late morning
hours and prevented increased surface warming from occurring. In the
case of Monterey, airport observations showed unbroken stratus
coverage throughout the entirety of Friday with the recorded high 6
degrees cooler than average. A similar scenario may occur along the
coast again today and help keep coastal temperatures slightly cooler
than originally forecast. Stratus coverage is expected to dissipate
for along the coast and inland by mid to late morning with sunny
skies returning during the afternoon. Chances for coastal drizzle
are lower than yesterday but cannot rule out the possibility of a
trace to a few hundredths of an inch accumulating.

An additional influence on today`s high temperatures is a weak
surface cold front that will move through the Bay Area today. This
will bring slightly cooler (3-4 degrees) temperatures inland where
stratus coverage is less widespread and has a less dominant
influence. Precipitation is not expected to occur with this system.
Despite temperatures being slightly cooler, highs should still be in
the mid to upper 70`s inland and upper 50`s to low 60`s along the
coast. All together, should be a pleasant day with seasonally warm
temperatures and sunny skies in the afternoon. Take some time to get
outside today and enjoy it!

&&

.LONG TERM...
(Sunday through Friday)
Issued at 300 AM PDT Sat May 18 2024

Upper level zonal flow will gradually deepen as a longwave upper
level trough moves into the Western United States over the weekend.
A weak warming trend will take place Sunday through the middle of
the work week with inland highs in the mid 70`s to low 80`s. Minor
heat risk is expected for individuals who are extremely sensitive to
heat Monday and Tuesday. Ensemble consensus largely shows inland
highs in the mid 70`s to low 80`s through mid-week with higher end
scenarios showing highs up to 85-87 degrees. Tuesday looks to be the
warmest day with probabilistic guidance showing a 50-60% chance of
portions of the North Bay and South Bay breaching the low to mid
80`s. Highs become more uncertain Thursday and Friday with ensembles
agreeing that temperatures will cool down but they did not reach an
agreement as to how significant this cool down will be.

Upper level troughing looks to persist through the week with
shortwave ridging building Friday into next weekend. Persistence is
key for this stratus forecast wherein stratus will continue to
develop along the coast overnight, clear out by mid to late morning,
and return during the early evening hours. A deeper marine layer is
expected to persist which will help keep stratus more confined to
coastal areas and not move as far inland.

&&

.AVIATION...
(18Z TAFS)
Issued at 1111 AM PDT Sat May 18 2024

Stratus this morning is bringing IFR/MVFR conditions to many
terminals. However, as stratus continues to recede and clearing
begins later this morning, expect VFR conditions to return for most
terminals. Winds to be onshore and breezy to moderate, reaching to
around 12-15 knots for most terminals this afternoon. Winds weaken
into the late night to become light, and stratus returns to a select
few coastal terminals (predominantly Monterey Bay) bringing MVFR/IFR
conditions. Terminals further inland are not expected to see much in
the way of impacts from stratus. However, the North Bay is likely to
see fog development in the early morning of Sunday, leading to
IFR/LIFR conditions.

Vicinity of SFO...VFR conditions return late this morning as stratus
recedes. Winds increase out of the west this afternoon to around 13
knots. At this time, low confidence in CIGs returning this evening
as a result of stratus. Highest confidence is in the development of
FEW-SCT low clouds filtering in through the Golden Gate and San
Bruno gaps, but maintaining VFR conditions through the overnight.
Winds light overnight, increasing Sunday afternoon to become breezy
once more.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...MVFR conditions linger into the early
afternoon today until stratus clears briefly to allow for VFR
conditions. VFR is likely to last only a few hours with a few low
clouds continuing to dot the sky despite clearing. Winds breezy and
onshore around 15 knots. Stratus pushes inland to bring a return of
MVFR CIGs in the early evening. Through the overnight, CIGs are
expected to lower to become IFR.

&&

.MARINE...
(Today through Thursday)
Issued at 854 AM PDT Sat May 18 2024

Winds out of the north strengthen to become strong and slowly
spread over the outer waters through the weekend. These stronger
winds are expected to last through most of the upcoming work week.
Gale force gusts build in the far northern waters today and are
expected to last through at least Monday. Expect hazardous
conditions and steeper wind waves from these building winds.

&&

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

     Gale Warning from 3 AM Sunday to 3 AM PDT Monday for Pt Arena to
     Pt Reyes 0-10 nm.

     Small Craft Advisory from 9 AM Sunday to 3 AM PDT Monday for Pt
     Reyes to Pigeon Pt 0-10 nm.

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

     Gale Warning until 3 AM PDT Monday for Pt Arena to Pt Reyes 10-
     60 NM.

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

&&

$$

SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...AC
MARINE...AC

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