485
FXUS66 KMTR 091746
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1046 AM PDT Thu May 9 2024

...New AVIATION...

.SYNOPSIS...
Issued at 245 AM PDT Thu May 9 2024

A warming trend that kicked off yesterday will continue today and
persist into tomorrow across the interior. Conditions begin to cool
near the coast on Saturday with interior areas remaining 5-15
degrees above average into early next week.

&&

.UPDATE...
Issued at 958 AM PDT Thu May 9 2024

Significant warming continues today, especially in the Sonoma
County valleys, where earlier this morning, many stations
reported temperatures 15 to 20 degrees above yesterday at the same
time. The Wind Advisory has been allowed to expire for the North
Bay interior mountains, with some notable wind gusts this morning
including 74 mph at Pine Flat Road, 68 mph at Mount Saint Helena,
and 54 mph at Mount Diablo. No changes to the forecast.

DialH

&&

.SHORT TERM...
(Today and tonight)
Issued at 245 AM PDT Thu May 9 2024

Clear sky conditions prevail across the region this morning as off
shore winds continue aloft. This will result in a warming trend
today with temperatures reaching the mid-to-upper 80`s across the
interior while 70`s will be common near the coast (closer to the
lower 80`s in places such as Santa Cruz and Downtown San Fransico).
This will bring Minor HeatRisk to the coast today with Moderate
HeatRisk across the North Bay, East Bay, and South Bay both today
and Friday.

A Wind Advisory remains in effect for the North Bay Interior
Mountains with gusts expected to reach 45 mph and may exceed 55 mph
in the Mayacamas Mountains through 8 AM this morning. Gusts in the
East Bay Hills are not expected to be widespread enough to warrant
an advisory, but Mount Diablo is expected to see gusts of 40-50 mph
this morning.

Overnight lows will be warmest in the North Bay and interior part of
the East Bay given the weakening offshore flow with temperatures
only expected to cool into the mid-to-upper 50`s. Elsewhere, low-to-
mid 50`s are expected overnight. The HRRR is showing signs of a
southerly surge arriving by late afternoon and into the overnight
hours. If were to occur, expect much cooler temperatures near the
coast on Friday.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 245 AM PDT Thu May 9 2024

Friday is expected to be the warmest day of the week, especially for
inland locations. Again, a southerly surge may cool conditions at
the coast, but the interior will still warm into the mid-to-upper
80`s to lower 90`s.

With the significant warm up expected for the rest of the week,
here`s a reminder of some 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.

As onshore flow increases, temperatures will cool regionwide.
However, interior areas will remain 5-15 degrees above average into
early next week.

From the previous forecaster: "Ensemble models and clusters are
showing that another ridge approaches the West Coast next week,
which could help maintain temperatures above the seasonal averages.
CPC products are showing temperatures above seasonal averages
continuing into the third week of May."

&&

.AVIATION...
(18Z TAFS)
Issued at 1038 AM PDT Thu May 9 2024

VFR thanks to offshore flow. Winds are still breezy to gusty at
times, but less than yesterday. LLWS is less with stronger sfc
winds and decreasing winds aloft - better mixing. Hi-res models
show a southerly surge developing tonight with S winds already
developing along the Central Coast. Low cig impacts tonight look
to be mainly confined to MRY Bay region.

Vicinity of SFO...VFR through the period. Breezy to gusty NE flow
persisting through this afternoon before switching onshore late.
Low clouds associated with S surge remain outside of Golden Gate
through tonight.

SFO Bridge Approach...similar to SFO.

Monterey Bay Terminals...VFR through early tonight. Included some
cigs for KSNS early Friday due to low cigs sneaking up the Central
Coast. Ensemble guidance shows a 60-70% chc for low cigs at KSNS.
KMRY on the other hand are much lower at 15-20% and will only do
SCT cigs.

&&

.MARINE...
(Today through Tuesday)
Issued at 958 AM PDT Thu May 9 2024

High pressure to the north will maintain light to moderately
northerly winds for most of the coastal waters today. However,
winds will be locally more southerly along the Big Sur and
Monterey Bay region. Otherwise, gentle breezes out of the north
and northwest continue through the weekend first portion of the
weekend. Dry weather continues through the forecast period as high
pressure dominates.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 PM PDT this afternoon for Pt Pinos
     to Pt Piedras Blancas 0-10 nm.

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...MM
MARINE...MM

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