444
FXUS66 KMTR 090606
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1106 PM PDT Wed May 8 2024

...New AVIATION...

.SYNOPSIS...
Issued at 1241 PM PDT Wed May 8 2024

Warming trend begins today  with the warmest temperatures expected
Thursday and Friday. Offshore winds continue through Thursday with a
Wind Advisory in effect for the North Bay interior mountains through
Thursday morning. A slight cooldown will begin this weekend and
continue into the early part of next week.

&&

.UPDATE...
Issued at 936 PM PDT Wed May 8 2024

The wind advisory remains in effect for the interior North Bay
mountains. While winds have come down in the valleys, a couple PGE
stations in the Mayacamas are reporting wind gusts above 50 mph.
Otherwise the forecast remains on track with dry and warm
conditions expected tomorrow. The temperatures have actually been
pretty slow to come down this evening, which may influence the
high temps tomorrow as the high resolution guidance adjusts before
the overnight forecast is issued.

&&

.SHORT TERM...
(This evening through Thursday)
Issued at 1241 PM PDT Wed May 8 2024

Summary:

* Warming trend begins today and peaks Thursday and Friday
* Minor HeatRisk throughout the region, Moderate HeatRisk in the
  interior Bay Area
* Breezy northerly winds continue today
* Wind Advisory for the North Bay interior mountains through 8 AM
  Thursday
* Gradual cooldown begins this weekend through early next week

The warmup has begun as temperatures across the region are generally
running around 5 to 10 degrees above the same time yesterday. A
ridge is building over the eastern North Pacific, building into
British Columbia and the Pacific Northwest through the next couple
of days. At the same time, an upper level low centered over the
northern Plains is elongating along a generally east-west axis, the
trough regressing into the Great Basin and breaking off into a weak
cut-off low. The combination of these two systems is leading to
north to northeast flow aloft, a situation that generally leads to
warmer temperatures in the area.

Forecast highs are generally reflecting today`s warming trend, with
interior locations seeing highs into the lower 80s, the Bayshore
seeing highs in the upper 70s, and mid to upper 60s expected along
the coast. Breezy north winds continue to develop with wind gusts up
to 20-25 miles per hour across the valley regions. The higher
elevations, especially in the North Bay, are in a lull through the
afternoon, but gusts up to 45 to 55 miles per hour are expected to
resume later this evening and continue through Thursday morning.
Thus, the Wind Advisory for the North Bay interior mountains
continues through 8 AM on Thursday.

Overnight lows will be quite warm across the Bay Area, with
temperatures on Thursday morning in the mid to upper 50s. The
Central coast will see somewhat cooler lows overnight in the upper
40s to low 50s. The heat event starts to peak on Thursday, with
interior highs in the mid to upper 80s and coastal highs in the low
to mid 70s. Of note, downtown San Francisco is currently expected to
reach 81 on Thursdsay; if the forecast verifies, it would be the
first 80-degree day in the city since last October. Winds are
expected to diminish through the day Thursday.

This section from yesterday continues to apply today: The seasonably
warm temperatures are causing a minor to moderate HeatRisk, meaning
that a low to moderate risk for heat related illnesses exists for
vulnerable populations (children, the elderly, pregnant women, or
those without adequate shelter or cooling), with moderate HeatRisk
values concentrated in the interior regions of the North, East, and
South Bays.

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.

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 1241 PM PDT Wed May 8 2024

Friday will be the second day of the peak heat event, and while
areas closer to the coast might see temperatures drop by a few
degrees, the interior areas should expect temperatures to rise even
further, as high as the lower 90s in the warmest locations. Cooling
begins Saturday, as a decaying ridge allows onshore flow to reassert
itself. Coastal regions will see the most cooling, and by Sunday,
should return to seasonal temperatures for this time of year
(generally, the low to mid 60s). At the same time, the interior will
continue to see highs in the low to mid 80s, warmer than the
seasonal average, through the early part of next week. 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...
(06Z TAFS)
Issued at 1106 PM PDT Wed May 8 2024

VFR through the TAF period, though stratus will begin to hug the
central coast in the early morning of Thursday as it begins to
travel northwards along the coast of California. At this time, not
expecting any intrusions of stratus over area terminals within the
current TAF period. Winds will remain elevated somewhat throughout
the night tonight for most terminals remaining above 7 knots. Winds
slowly turn throughout the morning and afternoon of Thursday to go
from NE to a more N/NW flow and increase to become breezy. By the
late evening of Thursday, winds will ease to become light.

Vicinity of SFO...VFR. Surface winds expected to ease to become
light tonight, though winds aloft will remain somewhat elevated, so
have included LLWS in the TAF to reflect this. In the afternoon of
Thursday, breezy N/NW winds return, but ease to become light and
variable into the late night.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the TAF period, though a
southerly surge of stratus will slowly creep its way up the coast,
hinting at the development of CIGs just beyond the current TAF
period. Otherwise, light winds overnight tonight and early Thursday
morning, though KSNS will see breezy southerly drainage winds in the
early morning. Come the afternoon, breezy onshore winds return.

&&

.MARINE...
(Today through Monday)
Issued at 908 AM PDT Wed May 8 2024

High pressure to the north and low pressure to the south will
maintain moderate to locally strong northerly winds over the
coastal waters and bays through tonight. The stronger northerly
winds will result if fresh steep swell today. By Friday, winds
are largely light to moderate across much of the waters. Wave
heights gradually diminish to around 5 to 7 feet by late week. Dry
weather continues through the forecast period as high pressure
dominates.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 8 AM PDT Thursday for CAZ504.

PZ...Small Craft Advisory until 3 AM PDT Thursday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...AC
MARINE...MM

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