065
FXUS66 KMTR 231705
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1005 AM PDT Mon Sep 23 2024

...New UPDATE, MARINE...

.SYNOPSIS...
Issued at 300 AM PDT Mon Sep 23 2024

Temperatures peak today and tomorrow with a Heat Advisory in effect
for the interior East Bay, South Bay, and the Santa Cruz Mountains
beginning at 11 AM PDT. Temperatures return to near seasonal
averages on Wednesday for the remainder of the extended forecast.

&&

.UPDATE...
Issued at 1005 AM PDT Mon Sep 23 2024

Satellite imagery shows that the stratus and fog deck has retreated
back to the immediate coast. In addition, cirrus clouds flowing
southwestward over the state of Nevada and into eastern California
hint at the offshore flow aloft, contributing to the warm
temperatures expected today. The RTMA analysis shows that
temperatures are warmer than this time yesterday across the higher
elevations, and colder than this time yesterday in the valleys.
Those cold trends are expected to disappear through the day as solar
heating kicks in. With a compressed marine layer (around 800 feet
via the Fort Ord profiler), not expecting a lot of stratus
development inland, although areas that do see stratus could see
mist or fog develop. Monitoring the marine layer evolution through
the day, as its inland extent tonight could determine how much
relief comes overnight, especially in the coastal ranges and near
San Francisco Bay.

The Heat Advisory for the interior East Bay, South Bay, and Santa
Cruz mountains goes into effect at 11 AM today, due to a risk for
heat-related illnesses for sensitive populations and people without
adequate hydration and/or cooling. Here`s a reminder about heat
safety:

* 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.

&&

.SHORT TERM...
(Today and tonight)
Issued at 300 AM PDT Mon Sep 23 2024

A Heat Advisory will go into effect later this morning
for the interior East Bay, South Bay and Santa Cruz mountains as
temperatures climb into the 90s to near 100 for many inland
locations. A warm airmass over our area defined by low/mid level
temperatures in the 90th percentile (H50 at -6.5C, H85 at 22C) or
slightly higher will peak today, though linger through tomorrow,
especially over the interior North Bay where a Heat Advisory will
remain in effect for Tuesday afternoon as well. With light winds
from the surface up to around H50, a lack of ventilation will lead
to some haze as well the next couple of days.

&&

.LONG TERM...
(Tuesday through Sunday)
Issued at 300 AM PDT Mon Sep 23 2024

By late Tuesday night into Wednesday, upper level flow, though still
relatively light will regain a westerly component as we begin to
feel the influence of a developing trough over the central
California coast. Cooler temperatures aloft will translate to near
normal surface temperatures for the remainder of the week into next
weekend as the upper low currently in our vicinity, is absorbed by a
broad, deepening trough out of the Gulf of Alaska that will persist
through the remainder of the extended forecast.

&&

.AVIATION...
(12Z TAFS)
Issued at 457 AM PDT Mon Sep 23 2024

Coastal stratus and fog /VLIFR-IFR/ moving locally inland this
morning otherwise it`s VFR.

Vicinity of SFO...VFR except tempo IFR 11z-15z today. Northwest
wind 5 to 10 knots becoming northeast near 5 knots this morning
then west to northwest near 10 knots this afternoon and evening.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Stratus and fog /VLIFR-IFR/ this morning,
conditions improving to MVFR-VFR by late morning. Mainly light
southeast winds, becoming west to northwest 5 to 15 knots in the
afternoon and early evening.

&&

.MARINE...
(Today through Saturday)
Issued at 1005 AM PDT Mon Sep 23 2024

High pressure remains over the Eastern Pacific keeping
northwesterly flow over the coastal waters through at least
midweek. Northwest winds will strengthen later in the week. Seas
rebuild to become rough in the outer waters by Thursday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 8 PM PDT Tuesday for CAZ510-515.

     Heat Advisory until 8 PM PDT this evening for CAZ512>514.

PZ...None.
&&

$$

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

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