411
FXUS66 KMTR 090011
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
511 PM PDT Sat Jun 8 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 1205 PM PDT Sat Jun 8 2024

Seasonal temperatures with breezy onshore winds will last through
Sunday before another warm up begins Monday.

&&

.SHORT TERM...
(This evening through Sunday)
Issued at 1205 PM PDT Sat Jun 8 2024

The stratus clouds have eroded everywhere except along the
immediate coast. Despite the clearing, area profilers and the
morning sounding confirm the marine layer is roughly 2,000 ft
deep. This is allowing cool air to infiltrate into the valleys
and keep the afternoon temperatures mild.

A short wave trough at 500 mb is approaching the coast this
afternoon. This wave will amplify and become a cut-off low SW of
the Channel Islands by Sunday evening. This synoptic change will
cause the mid-level winds to shift from southerly to northerly
over the next 36 hours. This change won`t be as obvious at the
surface. While the surface wind direction should veer a bit, the
weather Sunday will continue to be dominated by a deep marine
layer, morning stratus, and breezy onshore winds in the afternoon.
Broadly speaking, the temperatures Sunday will be similar to
Saturday and the seasonal averages.

&&

.LONG TERM...
(Sunday night through next Friday)
Issued at 1205 PM PDT Sat Jun 8 2024

Abandoned by the jet stream, the Southern California cut-off low
will continue to drift south Monday, allowing a ridge of high
pressure to build across the Bay Area. This ridge will cause the
marine layer to compress from 2,000 ft over the weekend to around 1,000
ft by Tuesday. While the cut-off low is part of the typical
offshore wind equation, we are missing the other piece of the
puzzle; strong high pressure over the intermountain West. While
weak offshore winds are expected at 700 mb Mon-Tue, they likely
won`t reach the surface. The combination of offshore winds aloft,
and a shallow marine layer will cause inland areas to warm above
seasonal averages from Monday through Wednesday. Tuesday currently
looks like the warmest day of the week, with inland highs in the
90s. Coastal areas will stay in the 60s and 70s.

By Thursday, an approaching trough will kick the cut-off low
inland, where it will quickly weaken. This will bring the return
of onshore flow and allow temperatures cool back to the seasonal
average.

&&

.AVIATION...
(00Z TAFS)
Issued at 505 PM PDT Sat Jun 8 2024

Moderate-high confidence in VFR through the TAF period at APC, LVK,
OAK, SFO, SJC, and STS. While stratus is currently eroding in the
Monterey Bay region, moderate confidence that IFR and MVFR ceilings
will return to MRY and SNS respectively tonight and into tomorrow
morning. Widespread VFR will prevail by tomorrow afternoon. Winds
will remain onshore through the TAF period.

Vicinity of SFO...Moderate confidence in VFR through the TAF period.
Winds will remain elevated and prevail out of the west through the
TAF period with gusts up to 25 knots to be expected through today as
well as tomorrow afternoon and evening. MVFR stratus could impact
the terminal early tonight and/or during the early-to-mid morning
hours of Sunday, will continue to monitor trends in models/guidance
and have the 03Z TAF amendment reflect.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Confidence is moderate on IFR stratus
returning to MRY and MVFR stratus returning to SNS tonight into
tomorrow morning. Winds will prevail out of the west/southwest
through the TAF period, becoming gusty tomorrow afternoon at SNS.
VFR to prevail by tomorrow afternoon.

&&

.MARINE...
(Tonight through next Friday)
Issued at 505 PM PDT Sat Jun 8 2024

Moderate to fresh northwesterly breezes continue to prevail due to
the gradient between subtropical high pressure and lower pressure
over the Southwestern United States. As high pressure slowly
progresses towards the coast, the pressure gradient will tighten,
causing the wind speed to increase through the weekend. A fresh to
strong northwesterly breeze will persist through next week.
Significant wave heights will mostly be dominated by wind driven
waves, though there is a moderate northwesterly swell and a low
southwesterly swell mixed in.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Sunday for SF Bay N of Bay
     Bridge.

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

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

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

     Small Craft Advisory from 9 AM Sunday to 9 AM PDT Monday for Pt
     Pinos to Pt Piedras Blancas 0-10 nm.

&&

$$

SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...Sarment
MARINE...Sarment

Visit us at www.weather.gov/sanfrancisco

Follow us on Facebook, Twitter, and YouTube at:
www.facebook.com/nwsbayarea
www.twitter.com/nwsbayarea
www.youtube.com/nwsbayarea