856
FXUS66 KMTR 220540
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1040 PM PDT Fri Jun 21 2024

...New AVIATION...

.SYNOPSIS...
Issued at 1253 PM PDT Fri Jun 21 2024

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, but
remain warm across the interior.

&&

.UPDATE...
Issued at 807 PM PDT Fri Jun 21 2024

No real changes needed for this evening and the ongoing forecast
is in fine shape. Satellite imagery reveals coastal stratus
starting to invade inlets and bays this evening as modest onshore
flow continues. With boundary layer flow being a bit less
perturbed than last night, the areal coverage of fog may be
slightly greater tonight compared to last night. That being said,
there aren`t any real signals from model guidance that widespread
dense fog will materialize, except maybe along the coastline. Interior
sections will see cooler conditions as mostly clear skies and
light winds promote ideal radiational cooling. Some of the
microclimates are already on display at this hour and portions of the
North Bay, the SF Peninsula, and interior Monterey County may dip
down into the upper 40s for overnight lows tonight into Saturday AM.

Otherwise, Saturday will be hot for locales away from the coast
with temperatures climbing into the upper 90s to near 105,
particularly across interior parts of the North Bay, East Bay, and
San Benito/Monterey counties. A Heat Advisory is in effect late
Saturday morning into Saturday evening. For more details, see the
short term discussion below.

&&

.SHORT TERM...
(This evening through Saturday)
Issued at 1253 PM PDT Fri Jun 21 2024

Tonight, temperatures will generally cool into the mid 50`s for most
locations away from the immediate coast with some upper 40`s in
those locations. However, warm temperatures will persist across the
higher elevations where temperatures will only dip into the upper
60`s to upper 70`s. Stratus will also return to the region this
evening, yet will penetrate less inland overnight as high pressure
compresses the marine layer.

Temperatures on Saturday will be the warmest of the week with
maximum temperatures reaching 105 degrees across the warmest inland
areas to mid 90`s in the interior valleys. This is where we have a
Heat Advisory in effect where HeatRisk reach moderate levels, across
the interior and higher elevations in the Santa Lucia Range. Near
the coast and areas just inland, mid 70`s to mid 80`s for the
Bayshore, and the 60`s and low 70`s along the Pacific coast as a
shallow marine layer remains in place.

Much of the interior is expected to see Moderate HeatRisk tomorrow,
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, the elderly, or pets unattended in vehicles.
* Use sunscreen if going to the coast or the pool.

&&

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

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...
(06Z TAFS)
Issued at 1040 PM PDT Fri Jun 21 2024

VFR tonight for inland terminals, while coastal terminals are
likely to see a brief period of low coastal clouds in the mid
morning (IFR CIGs), though confidence is only moderate on this.
Monterey Bay on the other hand is high confidence for developing
IFR CIGs, and dipping into LIFR territory overnight. Clearing is
expected in the mid to late morning of Saturday for all terminals
to VFR. Onshore and breezy winds return Saturday afternoon.

Vicinity of SFO...Currently VFR. VFR conditions last through the
majority of the night, though towards the mid morning of Saturday,
low clouds will begin to drift into the terminal vicinity. Current
thinking is that clouds may briefly and intermittently form IFR
CIGs, but confidence on this is only moderate. Winds overnight
expected to decrease and become light.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR CIGs last through the majority of the
night, though are expected to decrease to become LIFR in the mid
morning as higher pressure begins to build over the region. Clouds
clear and begin to erode beyond sunrise, leading to widespread
VFR conditions. Breezy westerly winds return in the afternoon
Saturday.

&&

.MARINE...
(Tonight through next Thursday)
Issued at 622 PM PDT Fri Jun 21 2024

Fresh northwesterly winds continue into the weekend with strong
gusts over the northern outer waters. These stronger gusts may
pose hazardous for small craft. Significant wave heights of 10-12
feet are expected over the outer waters through 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.

&&

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

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

     Small Craft Advisory until 9 PM PDT Saturday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...RGass
LONG TERM....DialH
AVIATION...Canepa/AC
MARINE...AC

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