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000
FXUS66 KMTR 181735
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1035 AM PDT Thu Apr 18 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 1206 PM PDT Wed Apr 17 2024

Warm temps persist into the weekend with a slight cool off Friday
as a weak trough pushes through. Increased cloudiness late week
with a chance of coastal drizzle. Otherwise seasonal going into
next week.

&&

.SHORT TERM...
(Today and tonight)
Issued at 1228 AM PDT Thu Apr 18 2024

The upper ridge now across the region will begin flattening today in
response to a weak disturbance upstream. The only real change in our
weather pattern as compared to yesterday will be slightly more
robust onshore flow. Therefore coastal areas should be a few degrees
cooler, while warm temperatures prevail inland. Look for highs
ranging from the lower to mid 60s along the coast tho the upper 70s
to around 80 in the warmer inland valleys. While most areas should
see plentiful sunshine outside of some higher clouds there is some
suggestion that low clouds and fog may develop around the Monterey
Bay this morning with the possible development of an Otter Eddy.
Regardless, any lower clouds, should they develop, will mix out by
mid to late morning.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 1228 AM PDT Thu Apr 18 2024

A trough will progress through the region on Friday into early
Saturday. This will bring increased cloud cover and breezy onshore
flow which will result in cooler temperatures. Some patchy
drizzle may also develop during the late night and morning hours
for orographically favorable areas along the coast.

The ridge rebuilds a bit over the weekend with a slight warming
trend. However onshore winds will keep things cooler by the coast.

By Wednesday the ridge will weaken as upstream troughing encroaches
on the area. This trough has a bit more moisture to work with, and
some ensemble members suggests that precipitation may return to part
of the area by mid to late week. However confidence at this point is
low so we`ll await future updates to gain greater clarity in the
details.

&&

.AVIATION...
(18Z TAFS)
Issued at 1034 AM PDT Thu Apr 18 2024

VFR to continue through the evening with MVFR-IFR returning
overnight for most stations. HREF indicates stratus will return
along the coast and move inland around 08-12Z with a slightly
earlier return (03-06Z) along the Central Coast. Low to moderate
confidence that fog will develop overnight at STS, SNS, and MRY
with guidance indicating moderate potential for LIFR conditions
at STS and SNS. For most stations, stratus looks to dissipate by
mid-morning but at a few stations (STS, APC, SNS, MRY)
dissipation looks to occur by late morning shortly after this TAF
period ends. Light to moderate SW to W winds will continue through
the day with winds becoming light and variable overnight.

Vicinity of SFO...VFR with MVFR returning overnight. Stratus will
return during the early morning with MVFR CIGs and only minor
impacts to visibility anticipated. Low confidence that fog will
develop at SFO but if lower CIGs do develop 12-16Z looks to be the
best time frame. Stratus is expected to clear out by mid-morning
between 17-18Z. Moderate W winds persist through the afternoon with
light, variable winds returning overnight. Moderate W winds return
by mid to late morning tomorrow.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR transitioning to MVFR-IFR overnight.
Guidance indicates MVFR and IFR CIGs will develop overnight with
increasing potential for LIFR CIGs to develop, particularly at SNS.
Low to moderate confidence that fog will develop at SNS and MRY. If
fog does develop, LIFR CIGs and significantly reduced visibilities
are likely. Confidence is higher for fog development at SNS than MRY
with guidance indicating high RH values and weak winds between 06-
16Z. Moderate W-NW winds during the day with light, variable winds
returning overnight.

&&

.MARINE...
(Today through Tuesday)
Issued at 1034 AM PDT Thu Apr 18 2024

Expect light to moderate winds into the weekend before breezy to
gusty northerly winds arrive Saturday afternoon. Wave heights will
start to build heading into the late weekend to early next week.
Another moderate period northwest swell arrives over the weekend
as well as another light, longer period (18 seconds) southerly
swell.

&&

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

$$

SHORT TERM...SPM
LONG TERM....SPM
AVIATION...Kennedy
MARINE...Kennedy

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