474
FXUS66 KMTR 171802
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1102 AM PDT Tue Sep 17 2024

...New AVIATION...

.SYNOPSIS...
Issued at 215 AM PDT Tue Sep 17 2024

Pleasant day today with below normal temperatures and clear skies
inland. Marine stratus keep a hold on the coastline. Another round
of very light rain possible Wednesday. Warming trend on tap for
the end of the week.

&&

.UPDATE...
Issued at 900 AM PDT Tue Sep 17 2024

Drizzle was reported in the higher terrain over the region this
morning with rainfall amounts between a trace and 0.04". Meanwhile,
low clouds will retreat to the coast by midday while incoming high
clouds spread over the region from the northwest. Otherwise, the
ongoing forecast remains on track this morning with no updates
anticipated at this time.

&&

.SHORT TERM...
(Today and tonight)
Issued at 215 AM PDT Tue Sep 17 2024

Not much notable change to the short term forecast over the last
24 hours. Today will be a fairly pleasant day with temps in the
60s and 70s area-wide. Nice and sunny inland, but the coastal
areas will hang on to the marine stratus thanks to a reforming
marine layer in the wake of the departing trough. There is a
slight chance of drizzle to end the day today along coastal areas
and ranges as the next upper trough approaches, bringing light
rain chances Wednesday.

&&

.LONG TERM...
(Wednesday through Monday)
Issued at 215 AM PDT Tue Sep 17 2024

The system coming in Wednesday still looking weaker on the wind
side. Thinking more in line with 20-25 mph gusts as the front
rolls trough Tuesday afternoon, and still confined to the coast
and gap areas. A bit of a better chance for thunder with the
Wednesday system with increased low level moisture and slightly
better cooling aloft. Still a low chance (~15%) that mainly exists
over the North Bay through the mid-to-late morning. Rain amounts
still look to be on the lower side, if any. Beyond Wednesday there
really isn`t much noteworthy to write about. A casual warm up is
on tap going into the weekend that will bring our temperatures to
around seasonal normals. By the end of the weekend, there is still
a good deal of disagreement in ensemble guidance regarding the
strength of a possible ridge pattern. More on that in the coming
days.

&&

.AVIATION...
(18Z TAFS)
Issued at 1102 AM PDT Tue Sep 17 2024

Stratus is expected to clear out of most airports between 18-20Z.
Most sites should clear by 19Z but additional tempos may be needed
from 19-20Z for any lingering stratus coverage. VFR conditions are
then expected through the afternoon before MVFR CIGs return late
this evening/overnight. Stratus is expected to return earlier along
the coast with MVFR CIGs to return 00-03Z at MRY and SNS. Winds
generally stay light to moderate with southwesterly winds gradually
becoming more west to northwesterly during the afternoon/evening
throughout the Bay Area. Drizzle chances increase everywhere, except
STS and APC, after 12Z with a few sites seeing drizzle chances
starting earlier between 05-06Z. Any precipitation that makes it to
the surface will be fairly light with totals less than a few
hundredths of an inch. Drizzle chances continue through the TAF
period but likelihood will decrease heading into late Wednesday.

Vicinity of SFO...MVFR becoming VFR by 19-20Z before MVFR CIGs
return overnight. Stratus is expected to return between 02-03Z
tonight and persist through late tomorrow morning. Drizzle chances
generally increase after 12Z through the end of the TAF period.
Scattered showers may become more likely after 15-18Z tomorrow but
confidence remains too low to include in TAF. West to southwest
winds become more moderate during the afternoon/evening before
weakening overnight.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Stratus coverage is dissipating at MRY and
SNS with patchy scattered clouds showing up on satellite. Ensemble
guidance indicates an early return of stratus around 00Z but a few
scenarios leaned towards an earlier return closer to 22-23Z. CIGs
are generally expected to stay MVFR overnight but there is some
potential for CIGs to become IFR overnight. Drizzle chances
generally increase after 06Z with the highest probability of drizzle
occurring after 12Z. Light, variable winds continue through the
remainder of the morning before more moderate west to northwest
winds return this afternoon.

&&

.MARINE...
(Today through Sunday)
Issued at 900 AM PDT Tue Sep 17 2024

Seas continue to abate and light to gentle northerly winds
persist through Tuesday. Hazardous seas return Wednesday as a cold
front arrives and brings moderate to fresh NW winds and rough
seas to the outer coastal waters. Locally stronger winds are
expected over the far northern outer waters.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&

$$

SHORT TERM...Behringer
LONG TERM....Behringer
AVIATION...Kennedy
MARINE...Kennedy

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