FXUS66 KMTR 271852
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1152 AM PDT Mon Jul 27 2026
...New AVIATION...
.KEY MESSAGES...
Updated at 1238 AM PDT Mon Jul 27 2026
- Breezy onshore winds expected each afternoon and evening through early
in the week
- Gradual warming starting midweek, with increasing Moderate HeatRisk
for interior locations heading into the weekend
- Elevated fire weather threat across the Diablo and Santa Lucia Ranges
this week
- Hazardous beach conditions at the Pacific Coast with an increased
risk for sneaker waves and rip currents thru mid-week
&&
.UPDATE...
Issued at 1016 AM PDT Mon Jul 27 2026
Overall the forecast seems to be on track, though forecast
temperatures are running 1-2 degrees below current observations.
We'll continue to examine the potential for hotter conditions
through this week with the latest guidance remaining consistent
with projections for Moderate HeatRisk for much of the interior
portions of the Bay Area and Central Coast, particularly across
the Diablo and Santa Lucia Ranges. Additional information will be
forthcoming with our full forecast update later today.
&&
.SHORT TERM...
Issued at 1238 AM PDT Mon Jul 27 2026
(Today and tonight)
Satellite imagery tonight continues to indicate marine stratus
struggling to make a push inland. The SFO-SAC pressure gradient is
around +4 which should result in an inland push by early morning,
and clearing by late morning, possibly early afternoon for the
terminals closer to the coast. Temperatures today are generally
right around normal for this time of year, warmer than normal at
higher elevations (~1500ft and higher). Breezy onshore flow
especially into the gaps and valleys across our area will continue
to dry fuels (see fire weather discussion for more details) and lead
to elevated fire weather concerns, especially at higher elevations
that will not see good RH recovery overnight. The most dangerous
portion of the forecast both today and through the remainder of the
week is the S-SW swell producing sneaker waves and riptides. One
count had over 25 water rescues across our Pacific coastline Sunday,
and likely more that didn't get reported to the media. Be extra
careful and never turn your back on the water.
&&
.LONG TERM...
Issued at 1238 AM PDT Mon Jul 27 2026
(Tuesday through Sunday)
Warmer temperatures are on the way, especially by the end of the
week into next weekend with increasing odds of more widespread
Moderate HeatRisk and potential heat advisories. However, there's
still plenty uncertainty in the magnitude of the increasing heat.
Cluster analysis maintains some troughing in our vicinity until late
next weekend into the first week of August. Deterministic guidance
struggled with Fausto this far out and expect that to continue with
Genevieve. Depending how far north Genevieve tracks will determine
how far north the persistent troughing over the EPAC gets nudged
north and allows more impactful H50 height rises and thickness
increases. The forecast remains dry throughout with the exception of
possible coastal drizzle associated with the marine layer. Fire
weather concerns will continue to increase through the extended
forecast as fuels continue to dry and cure. Avoid any activities
that could lead to a spark and ignition, fires that do start are
likely to spread quickly.
&&
.AVIATION...
(18Z TAFS)
Issued at 1151 AM PDT Mon Jul 27 2026
Widespread moderate onshore breezes (10-20 kt) prevail through the
afternoon and ease by sunset. Coastal sites and SFO have a high
chance of experiencing gusts in excess of 18 kt this afternoon.
Lingering clouds should dissipate no later than noon, except at HAF
where they will linger until ~22Z today. Model guidance tends to be
in agreement on a very shallow marine layer tonight of less than
1000 feet. Therefore, low confidence on how far inland it will push.
Highest confidence for IFR-MVFR ceilings is at our coastal sites
(HAF, MRY, and SNS). Depending on how warm SJC gets today, the bay-
land temperature contrast may be strong enough to develop a land
breeze overnight. Some models have hinted at the possibility, but
considering the winds will be light and the trend from the past few
nights, confidence is low at this time so the TAF was left with a
predominant NW flow.
Vicinity of SFO...VFR through the afternoon with moderate westerly
breezes. SFO will have another round of gusts around 30 kt today.
Medium confidence on stratus arrival tonight as low-end MVFR
ceilings may arrive between 09-12Z Tuesday and linger until ~18-19Z
tomorrow.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR anticipated shortly at MRY and then VFR
forecast to prevail through 05-09Z Tuesday. Gusty onshore flow ramps
up between 19Z-21Z with peak gusts in the 20-22 knot range. The
general model consensus is for MVFR/IFR cigs to re-develop over the
bay and infiltrate both sites by sunrise Tuesday. Confidence is low
to medium on the exact timing thanks to the slightly compressed
marine layer. The earliest arrival time for intermittent stratus
would be 05Z Tuesday at MRY and closer to 10Z Tuesday at SNS,
several hours later than climatological norm. Trends in satellite
will be monitored as earlier cloud development (or later as it has
been lately) across the bay may necessitate bumping the onset time
up earlier. Confidence is high that VFR will return at SNS before
the valid end time of the current TAF set. At MRY, confidence in a
return to VFR isn't as high, but ceilings should transition from IFR
to MVFR after 15Z Tuesday.
&&
.MARINE...
(Today through Saturday)
Issued at 947 AM PDT Mon Jul 27 2026
Fresh northwesterly breezes increase to strong today, persisting
through the week with frequent gale force gusts along the Big Sur
and Point Reyes coastal jet regions. Moderate seas build to rough
in the outer waters by tomorrow and continue through the week.
Distant tropical cyclones continue to send long period southerly
swells our way through the work week.
&&
.FIRE WEATHER...
Issued at 534 AM PDT Mon Jul 27 2026
Breezy onshore winds and critically dry afternoon RH through the
week will translate to an elevated fire weather threat. This threat
will persist through mid-week and potentially into the latter half
of the week and into the weekend. The most likely region for starts
and fire spread will be across the interior Central Coast where
Energy Release Components (ERC) are projected to climb above the
95th percentile. While morning RH recovery will moderate some
through the week, the shallow marine layer will equate to generally
poor overnight recovery for elevations at or above 2,000 feet
through Wednesday morning. This will be particularly true across the
Mayacamas, highest peaks of the East Bay Hills, the Diablo Range,
Santa Cruz Mountains, Santa Lucia and Gabilan Ranges. Nocturnal
drying (rapid decrease in RH through the pre-danw hours) may also
transpire which will increase the burn period or time in which fire
behavior may not diminish. Individuals across the area are advised
to avoid activities that may spark a fire. Fire crews are urged to
exercise extra caution when executing any prescribed burns,
especially where fuels, topography, and weather align.
&&
.BEACHES...
Issued at 145 PM PDT Sun Jul 26 2026
Tropical cyclones in the Eastern Pacific will continue to
generate 18-20 second (long-period) southwesterly swell which has
reached the coastline of the San Francisco Bay Area and Central
Coast. As such, sneaker waves and strong rip currents are the
primary concerns. However, breaking waves can reach up to 10 feet
along some south and southwest facing beaches and break points
(like Santa Cruz, Pacifica, and parts of Stinson or Ocean Beach).
This can be particularly surprising when wave heights increase
suddenly after a period of seemingly tranquil wave action.
In fact, sneaker waves can have 20+ minutes in between the larger
sets (breaking waves) with significant "flat/calm looking" times
between them. Due to the long period, sneaker waves are powerful
and can catch beachgoers by surprise and can result in people and
pets being swept into the cold, turbulent ocean. Rip currents are
strong enough to pull the strongest swimmers away from shore.
Check conditions before you head out! Swim near a lifeguard if
possible. Stay back from the beach, and away from jetties, piers,
beachside rocks, and other waterside infrastructure. Never turn
your back to the ocean and if you have small children or pets at
the beach, please keep an eye on them. Hazardous beach conditions
are anticipated to persist through Wednesday afternoon.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Wednesday afternoon for CAZ006-
505-509-529-530.
PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay-SF
Bay N of Bay Bridge.
Small Craft Advisory until 9 AM PDT Tuesday for Pigeon Pt to Pt
Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt
Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Reyes to
Pigeon Pt 0-10 nm.
Gale Warning until 9 AM PDT Tuesday for Pt Pinos to Pt Piedras
Blancas 0-10 nm.
&&
$$
SHORT TERM...JM
LONG TERM....JM
AVIATION...Navarrete/Bain
MARINE...Navarrete
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Prepared by Boulder-Creek.com Weather at: Mon Jul 27 12:30:03 PDT 2026
From the National Weather Service
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