961
FXUS66 KMTR 061810
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1110 AM PDT Thu Jun 6 2024

...New AVIATION...

.SYNOPSIS...
Issued at 215 AM PDT Thu Jun 6 2024

Hot inland otherwise expecting the beginning of a cooling trend
today mainly on the coastline then cooling reaches further inland
Friday through Sunday. Another potential hot period mid next week.

&&

.UPDATE...
Issued at 905 AM PDT Thu Jun 6 2024

Forecast looks on track today, overall running about 5-10 degrees
cooler than 24 hours ago. Still warm today with minor to moderate
Heat Risk for most. Some haze currently being observed may act to
keep temps a bit cooler than expected for areas more near the
coast. Still looking like we`ll shave off another 3-5 degrees for
tomorrow.

&&

.SHORT TERM...
(Today and tonight)
Issued at 259 AM PDT Thu Jun 6 2024

There are markedly different temperatures across the Bay Area and
north Central Coast depending on your location this morning. For
example there`s as much as 36F degree difference in temperatures
from 83F on Mt Tam (within the lower level temperature inversion -
a result of large scale sinking motion with the high pressure
system) vs mid 50s to upper 40s near sea level (due to a chilly
maritime influence) in Marin county at 2 am. Similarly it`s in the
lower 80s elsewhere along the ridgetops of the Bay Area, however
again it`s generally cooler with light breezes closer to sea level
nearest the bay and especially along the coastline.

Surface winds are settling in to a new regime in response to newly
developing adjustments in surface pressure gradients. Northerly
and southerly directed winds will join with the onshore wind and
begin to steepen today, this will bring about cooling from sea
level up through about 2500 feet today, best chances of this along
the immediate coast. At the moment, will let the Heat Advisory
continue as is, but we are closing in on the time when we can
think about reducing some of its coverage, possibly more so during
the day shift and/or evening shift. On the mid shift we`ll
continue to closely monitor the development of coastal stratus and
fog and marine layer depth.

Seeing the northerly pressure gradient gradually reducing is a
good sign, which will help give more equal weight to the onshore
gradient and wind today, the NAM forecasts the SFO-SAC gradient
to near 4 mb this afternoon. Sea surface temps in our coastal
waters vary from a few upper 40s to lower 50s, nice and chilly
which helps provide good potential for a sea breeze. HREF output
shows more coastal stratus and fog tonight.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 259 AM PDT Thu Jun 6 2024

A cooling trend continues into the weekend, onshore breezes will
extend farther inland. Daytime highs on the coastline cooler than
typical for this time in June, inland daytime highs will also cool
back to near typical in June. Weak upper level troughing moves across
the forecast area over the weekend then the global models forecast
increasing high pressure redeveloping over northern California early
to mid next week.

&&

.AVIATION...
(18Z TAFS)
Issued at 1033 AM PDT Thu Jun 6 2024

VFR prevails across all terminals late this morning and is
expected to persist through the remainder of the afternoon and
evening hours. Low stratus cloud field continues to gradually
build and expand over the water and will eventually begin to fill
in over coastal locations after midnight tonight and continue
through the remainder of the forecast period.

Vicinity of SFO...VFR is expected to prevail through the the
afternoon and evening hours with gusty winds later today beginning
to ease after sunset. Low stratus ceilings are expected to build
in during the overnight/pre-dawn hours and persist into Friday
afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR is expected to persist this afternoon
and evening with low stratus clouds encroaching on the terminals
at times. LIFR/IFR conditions are expected after sunset, likely to
persist through the remainder of the forecast period tomorrow.

&&

.MARINE...
(Tonight through next Tuesday)
Issued at 220 AM PDT Thu Jun 6 2024

Expect breezy northerly winds to persist through the day before
gradually easing into Friday. These winds along with rough seas
will lead to hazardous conditions for small craft. A moderate
period Northwest swell will continue impact the coastal waters
but will diminish Friday through Saturday before waves build
again towards the end of the period.

&&

.BEACHES...
Issued at 222 AM PDT Thu Jun 6 2024

A Beach Hazards Statement is in effect through Thursday evening.

Forecast remains on track. Moderate period swell is entering the
coastal waters at 14-17 seconds with heights varying 7-11 feet.
The would generate breaking waves of 8-15 feet with locally
higher waves at favored break points. Sneaker waves can run over
100 ft up a dry beach, pulling people in the water from rocks,
jetties, and beaches. Inexperienced swimmers should stay out of
the water. Observe the ocean for 20 minutes before relaxing on the
beach. The hot weather inland will lead to more people visiting
the beach this week. Know where lifeguards are, obey their
instructions, and never turn your back on the ocean!

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through this evening for CAZ006-505-509-
     530.

     Heat Advisory until midnight PDT tonight for CAZ503-504-506-510-
     512>516-518.

PZ...Small Craft Advisory until 3 AM PDT Friday for Pt Arena to Pt
     Reyes 0-10 nm.

     Small Craft Advisory until 9 PM PDT this evening for Pigeon Pt
     to Pt Pinos 10-60 NM-Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory until 3 PM PDT Friday for Pt Arena to Pt
     Reyes 10-60 NM.

&&

$$

SHORT TERM...Canepa
LONG TERM....Canepa
AVIATION...JM
MARINE...Murdock

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