-- Discussion containing changed information from previous version are highlighted. --
259
FXUS66 KMTR 301655
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
955 AM PDT Thu May 30 2024

...New SYNOPSIS, UPDATE, MARINE...

.SYNOPSIS...
-- Changed Discussion --
Issued at 955 AM PDT Thu May 30 2024

Weak ridging will bring a minor warming trend to the region
through the remainder of the work week. A trough will move into
the Pacific Northwest this weekend though, which will help
strengthen the onshore flow and deepen the marine layer, bringing
a slight reprieve to the warmer conditions. However, high pressure
will build back across the region by the middle of next week,
bringing a much more pronounced warming trend to the region,
especially across the inland areas. Inland areas could be upwards
of 10 to 20 degrees above normal, with a moderate heat risk by
Wednesday.
-- End Changed Discussion --

&&

.UPDATE...
-- Changed Discussion --
Issued at 955 AM PDT Thu May 30 2024

Water vapor imagery shows the upper level flow across California
is relatively zone this morning, with a few high clouds moving
across the far northern portion of the state. Meanwhile, visible
imagery shows a very patchy marine layer off the Santa Cruz and
Monterey coast line. A few low clouds did sneak into the Monterey
Bay this morning, but have since cleared, leaving us with somewhat
hazy skies this morning. Meanwhile, temperatures are currently
running similar to or slightly warmer than this time yesterday
morning. Expect this trend to continue into the afternoon hours,
as weak ridging starts to build over the region. This minor
warming trend will continue into Friday, before cooler conditions
develop for the weekend. At this point in time, the current
forecast seems to be handling this trends well, so no updates are
planned at this time. Palmer
-- End Changed Discussion --

&&

.SHORT TERM...
(Today and tonight)
Issued at 306 AM PDT Thu May 30 2024

Forecast highs today overall look to be about 3-5 degrees warmer
than yesterday for locations away from the coast. Looking at the
mid-to-upper 80s inland, upper 70s to lower 80s for the Bay
Shoreline, and a spread in the 60s along the coast. Very pleasant
day in store today with mostly clear skies and light winds. It`s
a slim chance with decreasing moisture aloft, but some locations
across the Bay Area and North Bay have a small chance to be
treated to a fantastic sunset with some high clouds overhead.
Skies clear out once again tonight as stratus returns along the
coast.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 306 AM PDT Thu May 30 2024

Much of the same Friday with temps largely unchanged. Slight
cooldown into Saturday where we`ll shave off 3-5 degrees and bring
temps right around seasonal normals for the rest of the weekend.
We may be facing another round of light drizzle across coastal and
high elevation locations Saturday morning as a weak trough deepens
the marine layer. This also means that we`ll see increase
overnight and morning cloudiness for areas that typically see
marine stratus. This pattern stays largely in place until about
Tuesday when we see a robust ridge begin to build over the western
half of the US. Medium range ensemble guidance is on board with
this pattern with high confidence. ECMWF Extreme Forecast Index
now highlights the midweek period next week for temps well above
average, further strengthening confidence in the need to message
early for heat-related issues. Currently thinking the Tuesday-
Thursday time frame will be the most impactful with moderate Heat
Risk across areas outside the daytime marine influence. In terms
of what temperatures will look like, current best forecast is in
the realm of 8-15 degrees above seasonal normals, with Wednesday
being the warmest. Details remain to be ironed out, but looking at
the long range guidance, it seems this may be our first larger
scale prolonged hot period across the west.

&&

.AVIATION...
(12Z TAFS)
Issued at 433 AM PDT Thu May 30 2024

VFR through much of the TAF period, though stratus will begin to
make a resurgence out of the south in the early morning of Friday,
bringing low clouds to terminals nearest to the coast. Monterey Bay
is likely to be the one exception, with IFR CIGs forming early
Friday. Otherwise, winds onshore and breezy this afternoon, then
easing into the nighttime to become light.

Vicinity of SFO...VFR through the TAF period. Not expecting
approaching stratus Friday morning to impact the terminal, though
this will be something to keep an eye on in future updates.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR conditions have developed around the
terminal this morning as a result of a patch of isolated stratus.
VFR conditions are expected to return after sunrise as stratus
begins to mix out. Onshore and breezy winds return in the afternoon,
later becoming light. In the early morning of Friday, stratus is
likely to bring IFR CIGs as low clouds push inland.

&&

.MARINE...
-- Changed Discussion --
Issued at 841 AM PDT Thu May 30 2024

Breezy to gusty winds last in the outer waters into the weekend
with gale force winds expected to return into Saturday morning.
Significant wave heights offshore build to 12 feet tonight with
but abating into Friday and through the weekend.
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&&

.MTR WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Friday for Pt Arena to Pt
     Reyes 0-10 nm.

     Small Craft Advisory from 3 PM Friday to 3 AM PDT Saturday for
     Pt Arena to Pt Reyes 0-10 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.

     Gale Warning from 3 PM Friday to 3 AM PDT Saturday for Pt Arena
     to Pt Reyes 10-60 NM.

     Small Craft Advisory until 3 AM PDT Saturday for Pigeon Pt to Pt
     Pinos 10-60 NM.
-- End Changed Discussion --

&&

$$

SHORT TERM...Palmer
LONG TERM....Behringer
AVIATION...AC
MARINE...Murdock

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