-- Discussion containing changed information from previous version are highlighted. --
459
FXUS66 KMTR 211111
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
411 AM PDT Fri Jun 21 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 1231 AM PDT Fri Jun 21 2024

Warm temperatures across the region today and Saturday. A Heat
Advisory comes into effect on Saturday for the interior regions with
a moderate risk of heat-related illnesses. Temperatures moderate
through the early part of next week.

&&

.SHORT TERM...
(Today and tonight)
Issued at 1231 AM PDT Fri Jun 21 2024

Marine layer stratus is developing again tonight with the Fort Ord
profiler showing a marine layer depth of 1500 feet and a robust
onshore pressure gradient, with SFO-SAC showing a +3.9 mb gradient
as of the last update. Expect the stratus to continue expanding
across the inland valleys through the night before the morning sees
the stratus pared back to the immediate coastal regions. Tonight`s
lows remain in the upper 40s to mid 50s across the lower elevations,
and into the upper 50s to lower 60s in the higher elevations.

Today sees the first day of a significant warmup in temperatures as
an upper level trough fades into a ridge moving into the western
United States. High temperatures today will range from the mid 80s
to the mid 90s in the inland valleys, perhaps close to or at 100 in
the warmest spots of the northern North Bay, eastern East bay, and
southern Central Coast. Elsewhere, expect highs near the low to mid
60s along the coast and in the 70s for the Bayshore.

We begin to see Moderate HeatRisk in some of the interior regions
today, most notably the interior East Bay, South Bay, and southern
Salinas Valley. This means that there is a risk of heat-related
illnesses for most people sensitive to heat, including children, the
elderly, pregnant women, those working or living outside, and those
with certain medical conditions. Here are heat safety tips:

* Stay hydrated and drink plenty of fluids.
* Wear lightweight, light-colored clothing.
* Reduce time spent outdoors or stay in the shade.
* Never leave people or pets unattended in vehicles.
* Use sunscreen if going to the coast or the pool.

&&

.LONG TERM...
(Saturday through Thursday)
Issued at 1231 AM PDT Fri Jun 21 2024

Temperatures peak on Saturday, with highs ranging from the mid 90s
to the mid 100s in the inland valleys, the mid 70s to mid 80s for
the Bayshore, and the 60s and low 70s along the Pacific coast. A
Heat Advisory will be in effect on Saturday for the interior North
Bay mountains, East Bay, South Bay, and Central Coast, where
Moderate HeatRisk continues through the day.

Sunday should be noticeably cooler with an upper level trough to our
west beginning to promote stronger onshore flow. High temperatures
will drop into the mid 80s to the low 90s in the interior valleys
(perhaps close to 100 in the warmest spots), the 70s into the lower
80s along the Bayshore, and the upper 50s to the 60s along the
coast. Expect these temperatures to continue into the next work
week. Beyond that, CPC outlooks continue to suggest chances for
temperatures above seasonal averages (around 33-50% probability) and
precipitation near or below seasonal averages into the first few
days of July.

&&

.AVIATION...
-- Changed Discussion --
(12Z TAFS)
Issued at 410 AM PDT Fri Jun 21 2024

Stratus remains socked in over all terminals along the coast
creating a mix of MVFR/IFR/LIFR conditions. High confidence that
stratus will lift and erode back to the coast, allowing for VFR to
prevail through the remainder of the TAF period, except KMRY where
stratus is expected to return Friday evening. Models do hint at
MVFR/IFR conditions returning for some terminals, but with the
warmer temperatures, and drier conditions, confidence were low to
include lower CIGs at this moment. Onshore winds will remain light
to moderate before rebuilding Friday afternoon with possible gusty
winds through coastal gaps and passes.

Vicinity of SFO...IFR will continue until the early morning where
VFR will return. Models hint at MVFR ceilings returning Friday
night, but with the ridging pattern, there is a higher chance for
VFR will prevail for the remainder of the TAF period. Winds will
become breezy and gusty up to 23-25 knots Friday afternoon,
before returning to light Friday night.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR conditions, but there are chances for
temporary LIFR ceilings for the next few hours. VFR conditions are
expected near 17-18Z. KMRY IFR/MVFR conditions may linger a bit
longer into Friday morning, but higher confidence between 18-19Z.
Models show good agreement of possible IFR/LIFR conditions for KMRY
Friday night, but still some uncertainty on timing and ceiling
height.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
(Today through Wednesday)
Issued at 410 AM PDT Fri Jun 21 2024

  Moderate to fresh northwesterly winds persist tonight and
prevail into the weekend, with strong near gale forced winds over
the northern outer waters. These stronger gusts may pose hazardous
for small  craft. Significant wave heights of 6-8 feet will
persist until the end of the week, then build back up to 10-12
feet over the outer  waters for the weekend, when northwest winds
increase once again  over much of the waters. Light southerly
swell continues to move  through the waters today, accompanied by
moderate NW swell.
-- End Changed Discussion --

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CA...Heat Advisory from 11 AM to 10 PM PDT Saturday for CAZ504-510-
     513>518.

PZ...Small Craft Advisory until 9 PM PDT Saturday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM.
-- End Changed Discussion --

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...SO
MARINE...SO

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