011
FXUS66 KMTR 220545
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1045 PM PDT Tue May 21 2024

...New AVIATION...

.SYNOPSIS...
Issued at 1237 PM PDT Tue May 21 2024

Summer-like pattern to persist through Thursday. Temperatures are
forecast to dip below seasonal averages by the upcoming weekend
as an upper level trough impacts the region.

&&

.UPDATE...
Issued at 853 PM PDT Tue May 21 2024

A mostly clear night across the region right now, with the only
clouds on satellite imagery showing up around the southern half of
the Monterey Bay coastline and the southern Monterey County
coast. As has been the pattern these last couple of nights,
stratus will be mainly confined to the coastal regions south of
San Francisco and intruding inland across the Monterey Bay region
and down the Salinas Valley. No changes to the forecast at this
time.

DialH

&&

.SHORT TERM...
(This evening through Wednesday)
Issued at 1237 PM PDT Tue May 21 2024

The broad tilted upper level troughing pattern over California has
brought some weak offshore winds over interior areas, causing some
warmer temperatures and drier conditions. The offshore flow will
help inhibit some of the marine layer from reaching inland tonight
into Wednesday morning allowing for another blue sky morning for
interior regions. On the other hand, the weak onshore flow along the
coast will bring some low clouds along the coastal areas, especially
near Monterey Bay and Salinas Valley tonight. Models show interior
regions will be on the drier side this evening with minimum relative
humidity values between 14-30%.

Overnight temperatures are relatively the same as last night with
minimums in the mid to upper 40`s to low to mid 50`s. Some isolated
areas will see a slight increase 2-3 degrees higher. Temperatures
will start to trend cooler on Wednesday, but still will be
relatively warmer than usual with inland max temperatures in the low
80s to high 70s, as coastal areas will see temperatures in the upper
50s to 60s. The onshore flow along the coast will increase on
Wednesday, which will help increase some relative humidity values
between 20-55%.

&&

.LONG TERM...
(Wednesday night through next Monday)
Issued at 1237 PM PDT Tue May 21 2024

The low pressure system that sits in the northwest, will drop south
a bit on Thursday and will move across the Pacific northwest over
the weekend, which will bring stronger onshore flow and cooler
temperatures. Thursday will start to see max temperatures in the mid
70s inland and upper 50s to 60s along the coast. Friday through the
weekend, max temperatures are expected to drop between 5 to 7
degrees below average over the weekend with mid 50s to low 60s
coastline and upper 60s to low 70s inland. With the stronger onshore
flow, expect the gloomy mornings pattern to continue along the
coast, with slow clearing in the mornings. Ensemble models show
no impactful precipitation associated with this trough as it
moves through our area this weekend, but if precipitation does
occur this weekend, expect the best chance to occur near the
coast. On Sunday into Monday, a weak ridging will develop over our
area bringing back some slightly warmer temperatures.

&&

.AVIATION...
(06Z TAFS)
Issued at 1043 PM PDT Tue May 21 2024

VFR through the TAF Period for all but the Monterey Bay, where
periodic IFR/MVFR ceilings initially will become more prevalent
later tonight into late Wednesday morning. Expect winds to become
light to moderate overnight for most areas. Moderate winds build
into Wednesday afternoon, with gusty winds expected along the
immediate coast, in portions of the North Bay, and around the SF
Bay.

Vicinity of SFO...VFR through the TAF period. Expect moderate west
winds overnight. Gusty westerly winds arrive Wednesday afternoon
with peak gusts around 26 kts. These winds reduce into the early
night, but stay moderate.

SFO Bridge Approach...Similar to SFO

Monterey Bay Terminals...Periodic IFR/MVFR ceilings early will
become more prevalent later tonight into late Wednesday morning.
Expect light winds overnight with more moderate westerly winds
arriving Wednesday afternoon and lasting into the night.

&&

.MARINE...
(Tonight through next Monday)
Issued at 853 PM PDT Tue May 21 2024

The strong and gusty northwest winds continue over the coastal
waters through the mid week, with gale force gusts across the
outer waters. Expect hazardous conditions and steeper wind waves
with these strong winds. The pattern changes and winds are
expected to reduce into the late week

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM to 9 PM PDT Wednesday for Mry Bay.

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

     Gale Warning from 9 AM Wednesday to 3 AM PDT Thursday for Pigeon
     Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

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

     Small Craft Advisory from 9 AM Wednesday to 3 AM PDT Thursday
     for Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras
     Blancas 0-10 nm.

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

&&

$$

SHORT TERM...SO
LONG TERM....SO
AVIATION...SPM/Murdock
MARINE...Murdock

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