FXUS66 KMTR 291057
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
357 AM PDT Mon Jul 29 2024

...New SYNOPSIS, SHORT TERM, LONG TERM, AVIATION, MARINE...

.SYNOPSIS...
Issued at 355 AM PDT Mon Jul 29 2024

Near to slightly below seasonal normal temps to start this week.
Gradual warm up expected into this weekend with above average
temps by the latter half of the week.

&&

.SHORT TERM...
(Today and tonight)
Issued at 355 AM PDT Mon Jul 29 2024

Current satellite showing thick stratus coverage over most of the
populated areas this morning. Still holding on to a very deep
(~2000 ft) marine layer today with decent moisture return in the
onshore flow, so most coastal locations will likely hold on to
most of their cloud cover through today. There may also be some
patchy drizzle along the coast and favored upslope areas this
morning. Not much more than the past couple of mornings, but a few
select locations have the possibility of picking up a trace or a
hundredth.

&&

.LONG TERM...
(Tuesday through Sunday)
Issued at 355 AM PDT Mon Jul 29 2024

The larger scale pattern continues to promote a deep marine layer
and patchy drizzle each morning through mid week as an elongated and
relatively stagnant upper low sits over the north and west portions
of the country. By mid week, a gradual pattern change begins to take
place as a ridge builds over the western US. Gradually building
500mb heights promote a slow warm up into the weekend with temps
about 5-7 degrees above normal by Saturday. No major hazards to
speak of with confidence in the forecast period. A couple of things
to note: By the end of the week, several inland locations will be
seeing temps in the mid-to-upper 90s to near 100, leading to a
moderate risk of heat-related illness. Will continue to watch these
inland areas for any heat highlights as needed. Also, ensemble
guidance reasonably advertises a weak slug of monsoonal moisture
being advected into central and northern CA around the periphery of
the ridge by about Friday night into Saturday morning. At the
moment, nothing stands out in terms of dry lightning potential, but
will continue to watch this as well.

&&

.AVIATION...
(12Z TAFS)
Issued at 355 AM PDT Mon Jul 29 2024

Mix of LIFR directly along the coast and IFR-MVFR everywhere else.
The marine layer has compressed slightly compared to earlier in the
evening which may result in some sites that are currently on the IFR-
MVFR border to temporarily transition from low end MVFR CIGs to high
end IFR CIGs. Moderate confidence that CIGs will clear between 18-
21Z for most airports. Ensemble guidance indicated some uncertainty
if stratus would clear from SFO, OAK, and MRY today. For OAK and
SFO, leaning towards stratus becoming more scattered by 20-21Z due
to decreasing RH values. Widespread MVFR-IFR CIGs will return
tonight with moderate confidence on the current timing. Onshore flow
persists through the forecast period with moderate, gusty winds
returning during the afternoon.

Vicinity of SFO...IFR becoming VFR by the early afternoon. IFR CIGs
are expected to persist through late morning before CIGs start to
rise and eventually become more scattered. Low to moderate
confidence that CIGs will clear this morning. More pessimistic
ensemble guidance indicates CIGs may stick through the day. In
comparison, the NBM and GFSLAMP indicate clearing will briefly
develop this afternoon/evening before CIGs return. The KSFO-KWMC
pressure gradient is forecast to be between 5 to 10 hPa and shows
that strong onshore flow is expected to develop this afternoon/evening.
Gusts are currently forecast to reach 29 kts but some ensemble
guidance suggests gusts between 30-31 kts may develop.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...LIFR conditions becoming MVFR at MRY by
late this morning. Ensemble guidance shows MRY on the border of
stratus clearing vs not clearing. For now, leaning on the side of
stratus not clearing due to high RH values forecast throughout the
day. IFR-LIFR CIGs will return to MRY by the early evening with some
potential for decreases in visibility by the late evening. IFR
becoming VFR at SNS by late this morning before IFR CIGs return late
this evening. Onshore flow continues through the period with winds
becoming more moderate during the afternoon.

&&

.MARINE...
(Today through Saturday)
Issued at 355 AM PDT Mon Jul 29 2024

Mild conditions continue over the waters with gentle to moderate
winds and fresh gusts continuing through the forecast period.
Occasional borderline fresh to strong gusts are possible directly
along the Big Sur Coast through this evening. Significant wave
heights will build slightly by the middle of the week but remain
below small craft advisory criteria

&&

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

$$

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

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