395
FXUS66 KMTR 181842
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1142 AM PDT Tue Jun 18 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 850 AM PDT Tue Jun 18 2024

Upper level trough will remain over the region through the next
several days, with breezy onshore winds and temperatures near
seasonal averages prevailing through Thursday. The trough will
weaken for Friday and the weekend, with warmer conditions
developing once again across the inland areas.

&&

.UPDATE...
Issued at 850 AM PDT Tue Jun 18 2024

Water vapor imagery shows a broad trough of low pressure over the
West this morning, with another disturbance poised off the
Northern California Coast. Meanwhile, visible imagery is showing
quite a bit of smoke filtering into the area from the Site Fire in
Colusa County. For the most part, it appears this smoke is aloft,
as all of our surface observing sites are reporting 10 SM and the
majority of the air quality sites are satisfactory to acceptable
this morning. Visible imagery is also showing quite a bit of high
cloud cover associated with this next disturbance, so expect
increasing clouds as we go through the day today and tonight. Also
expect onshore flow to increase once again this afternoon, but
not anticipating the onshore flow to be quite as strong today, as
we have seen the past couple of days. Daytime temperatures will be
similar to what we saw yesterday, maybe a degree or two warmer
inland and a degree or two cooler along the coast. Current
forecast seems to be handling these trends will, so no update is
planned at this time. Palmer

&&

.SHORT TERM...
(Today and tonight)
Issued at 123 AM PDT Tue Jun 18 2024

Winds are generally light this morning with the upper level trough
that drove the intense daytime winds progressing eastward across the
Intermountain West. Mid to high level clouds will flow over the
region today. Breezy onshore winds will develop this afternoon, but
they won`t be as intense as what we`ve seen this last weekend. Low
temperatures this morning will generally be in the low to mid 50s in
the lower elevations, to the upper 50s and around 60 in the higher
elevations. High temperatures today will range from the upper 50s to
mid 60s along the coast, to the mid to upper 70s along the Bayshore,
and the mid 80s to lower 90s in the inland valleys.

Smoke from the Point Fire in northwestern Sonoma County and the
Sites Fire in Colusa County is expected to travel towards the south
and southeast, impacting the Bay Area and Central Coast with haze
and moments of smoke. Although the Red Flag Warning for the North
Bay interior mountains was allowed to expire last night, elevated
fire danger remains across the interior regions. The air remains
very dry with daytime relative humidities in the 10-30 percent range
across the inland areas and the coastal ranges, with breezy onshore
winds gusting up to 20-30 miles per hour in the afternoon. Humidity
recoveries overnight are expected to progressively improve through
the week, but remain poor across the interior mountains and the
Santa Lucias.

&&

.LONG TERM...
(Wednesday through Monday)
Issued at 123 AM PDT Tue Jun 18 2024

A weak upper level trough develops over the state, continuing to
hover over the area for the next few days and promoting the
redevelopment of the marine layer and its associated stratus clouds.
Temperatures dip on Wednesday with highs in the upper 70s to mid 80s
in the inland valleys to the mid 50s to lower 60s along the coast,
before Thursday sees a few degrees of warming.

By Friday, the trough will erode as a ridge builds into the western
United States. The warmest temperatures are expected on Saturday,
where highs will range from the 90s to lower 100s for the inland
regions, the mid 70s to low 80s for the Bayshore, and the low to mid
60s for the coast.

&&

.AVIATION...
(18Z TAFS)
Issued at 1141 AM PDT Tue Jun 18 2024

VFR through the TAF period for the majority of terminals, with the
exception of Monterey Bay. Smoke continues to linger throughout the
region this morning bringing hazy skies but is expected to clear
towards the afternoon as onshore flow helps push smoke eastward.
That being said, winds expected to be onshore and breezy today,
though not as gusty as in previous days. A few gusts nearing 20 kt
are not out of the question for coastal terminals, higher at SFO. In
the late night, winds ease to become light for the majority of
terminals. Stratus will begin to creep up the coastline, and will
begin to advect inland where it is expected to bring MVFR CIGs to
KOAK and KMRY. Terminals elsewhere are likely only to see FEW low
clouds develop in the overnight.

Vicinity of SFO...Winds W/NW and moderate this afternoon, gusting
nearly to 30 kt at the highest. Winds ease into the late night, but
are not expected to become light until the early morning of
Wednesday. That aside, VFR expected through the TAF period, though
stratus pushing inland in the overnight hours is likely to bring SCT
low clouds. At this time, confidence is low in MVFR CIG development
for SFO in the night tonight.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the evening tonight with breezy
NW winds. By the late evening, winds decrease and stratus is
expected to form MVFR CIGs. However, there is some question as to
whether CIGs this evening will develop at IFR altitudes rather than
MVFR initially, as the Ft. Ord Profiler currently shows a marine
layer very near to the surface. Confidence on CIGs initially
developing at MVFR levels is only moderate.

&&

.MARINE...
(Today through Sunday)
Issued at 1141 AM PDT Tue Jun 18 2024

Fresh and gusty northwesterly winds continue. Gusty winds will
diminish overall towards late Wednesday with strong breezes
persisting over the northern outer waters through the weekend.
Significant wave heights will build to 9-11 feet today, abate
through Friday, and build back up to 10-12 feet towards the end of
the the weekend as larger northwesterly swell enters the waters.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this
     evening for Mry Bay-SF Bay N of Bay Bridge.

     Small Craft Advisory from 9 AM to 3 PM PDT Wednesday for SF Bay
     N of Bay Bridge.

     Small Craft Advisory from 3 PM to 9 PM PDT Wednesday for Mry Bay.

     Small Craft Advisory until 9 PM PDT Wednesday for Pt Arena to Pt
     Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 9 AM PDT Wednesday for Pigeon Pt to
     Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM-Pt Reyes to
     Pigeon Pt 0-10 nm.

     Small Craft Advisory until 3 AM PDT Wednesday for Pigeon Pt to
     Pt Pinos 0-10 nm.

     Small Craft Advisory from 9 PM Wednesday to 9 AM PDT Thursday
     for Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...Palmer
LONG TERM....DialH
AVIATION...AC
MARINE...AC

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