FXUS66 KMTR 301928
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1228 PM PDT Thu Jul 30 2026
...New SHORT TERM, LONG TERM, BEACHES, FIRE WEATHER...
.KEY MESSAGES...
Updated at 1216 PM PDT Thu Jul 30 2026
- Gradual warming trend through Saturday with Moderate HeatRisk
in the interior through the early part of next week
- Elevated fire weather threat across the interior North and East
Bays, and the Diablo and Santa Lucia ranges through the early
part of next week
- Hazardous beach conditions across the Pacific Coast with an
increased risk for sneaker waves and rip currents through the
weekend
&&
.SHORT TERM...
Issued at 1216 PM PDT Thu Jul 30 2026
(This evening through Friday night)
Generally clear skies prevail over the region with limited patches
of stratus lingering over the western side of San Francisco, along
the coast of the San Mateo Peninsula down to Pillar Point, and at
the immediate coast of the Monterey Bay region. Today will be the
first day of a warming trend that will dominate the weather pattern
for the next few days and bring temperatures above seasonal averages
to the inland regions, driven by a building high pressure system
expanding into California from the Desert Southwest. High
temperatures will range from the middle 80s to middle 90s across the
inland valleys, up to around 102 within the warmest spots of
southern Monterey and San Benito Counties, the lower 70s to lower
80s along the Bays, and the lower to middle 60s along the Pacific
coast. An onshore push will develop this afternoon and evening,
bringing gusts of 25 to 35 mph along the coast, through gaps and
passes, and within the Salinas Valley.
Tonight, expect the building high pressure system to compress the
marine layer, limiting any stratus and fog impacts to the immediate
coastal regions. Low temperatures on Friday morning range from the
middle to upper 50s in the valleys, to the 60s and lower 70s within
the thermal belts. Highs on Friday will continue to warm with
temperatures around a couple degrees warmer than today's across most
of the region, save the immediate coast where the compressed marine
layer keeps the region cooler.
Patches of Moderate HeatRisk develop in the interior on Friday,
followed by more widespread Moderate HeatRisk in the interior
Saturday through the early part of next week. This corresponds to a
moderate risk for heat related illnesses for sensitive populations,
including children, the elderly, pregnant women, people with certain
medical conditions, and people who work or live outdoors without
adequate shelter or hydration. Follow these tips to avoid heat-
related illnesses:
* 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...
Issued at 1216 PM PDT Thu Jul 30 2026
(Saturday through next Wednesday)
Saturday looks to be the warmest day of this strand of warming with
triple digit highs possible in the far interior regions of northern
Sonoma, northeastern Napa, and eastern Contra Costa counties, while
southern Monterey County sees highs reaching 105 with some isolated
and heavily favored locations making a run for 110. Elsewhere the
inland valleys remain in the 90s while downtown San Francisco and
Oakland hover in the middle 70s to lower 80s. On Sunday, a trough
passing by the Pacific Northwest will interrupt the building ridge
and cause temperatures to plateau, but large scale ridging returns
the next day and could continue into the middle of the next week.
Regarding potential strong winds across the coastal waters this
weekend, the ECMWF EFI backed down a little bit from what the
previous forecaster was seeing last night, but are still showing
high EFI values with a strong shift of tails. Or in layman's terms,
there's a strong signal for strong winds and a relatively high
probability for remarkably strong winds, a "boom" situation, if you
will. The PG&E WRF model continues to show a swath of storm force
gusts over 60 mph across the northern waters off the coast of Sonoma
and Marin counties, but it's almost alone in depicting this, with
the deterministic GFS and the experimental RRFS showing isolated
storm force gusts in the area while the NAM12 and deterministic
ECMWF keep wind gusts at gale force. Will be interesting how the
other high resolution models, namely the higher-resolution NAM and
the HRRR, depict the wind gusts in this are where the time comes.
For now, there wasn't enough confidence to bump up the wind gusts
for the weekend.
In addition, the upper level pattern could bring us a couple of
offshore bursts over the region, with a notable pulse Sunday night
into Monday particularly across the North Bay and SF Bay regions. As
noted by the previous forecaster, the fire weather concerns
regarding nocturnal drying and downslope warming are obvious, but
that downslope warming could also cause coastal temperatures to be
much warmer than the forecast if it extends through Monday.
As a final note, beach hazards and fire weather concerns continue
into the weekend. See the BEACHES and FIRE WEATHER sections for more
details. One less spark, one less fire, and never turn your back to
the ocean!
&&
.AVIATION...
(18Z TAFS)
Issued at 1124 AM PDT Thu Jul 30 2026
Beginning the day with widespread VFR conditions, yay! Onshore winds
increase to 10-15 kt by the early afternoon and ease to ~5 kt
overnight. Winds at STS and APC remain more S-SW meanwhile sites
located south of the Golden Gate remain W-NW. As the ridge continues
to move westward and the 500 mb heights over our region increase,
the marine layer tonight will be compressed to around 1000 feet or
less. This will confine stratus coverage to coastal sites only (HAF,
MRY, and SNS), potentially bringing borderline IFR-LIFR ceilings.
The compressed marine layer increases the chances for patchy coastal
drizzle and fog, though confidence is low on the exact duration and
timing. Elsewhere should remain VFR through the TAF period.
Vicinity of SFO...Gentle onshore breezes increase to ~15 kt this
afternoon (20-21Z) with SFO experiencing another round of gusts
around 25 kt. Low confidence on the development of MVFR ceilings
this TAF period. Most model guidance (HREF, REFS, LAMP, and NBM)
tends to agree on limited stratus coverage tonight. If the marine
layer deepens beyond 1000 feet, there may be a chance for stratus to
trickle over SFO and OAK around 10-12Z. However, the atmosphere
seems to be to dry at 925 mb and above, which helps to limit the
expansion of stratus.
SFO Bridge Approach...Similar to SFO. Winds may be a couple knots
lower than SFO.
Monterey Bay Terminals...VFR through the day. Onshore winds increase
to ~10-12 kt this afternoon with gusts around 18-22 kt. A compressed
marine layer will also delay the arrival of IFR ceilings compared to
the previous night. As a result, they may arrive around 11-13Z,
impacting MRY first and then SNS. Ceilings may intermittently become
LIFR at OVC003-004, but low confidence on the exact timing. If
conditions do become LIFR, coastal drizzle and patchy fog is
possible which will impact visibility to around 1-2 SM. MRY has a
higher chance of visibility impacts under these conditions compared
to SNS.
&&
.MARINE...
(Today through Tuesday)
Issued at 908 AM PDT Thu Jul 30 2026
Northwesterly breezes remain fresh to strong with embedded near
gale force gusts into the weekend. Wind driven moderate seas
build to rough by Sunday. Northwest winds increase to gale by the
end of the weekend as well. Our coastal waters continue to
experience a long period southerly swell from distant tropical
activity.
&&
.FIRE WEATHER...
Issued at 1216 PM PDT Thu Jul 30 2026
The overall fire weather picture remains similar to the previous
discussion, with elevated fire weather threats persisting at the
higher elevations through the weekend and possibly beyond.
Overnight RH recovery remains moderate to poor at locations at or
above 2,000 feet with values between 35 to 45 percent, with some
favored locations struggling to even reach 25 percent. This will
be particularly true across the Mayacamas, highest peaks of the
East Bay Hills, the Diablo Range, the Santa Cruz Mountains, the
Santa Lucia and Gabilan Ranges. Nocturnal drying (rapid decrease
in RH through the pre- dawn hours) may also transpire which will
increase the burn period or time in which fire behavior may remain
active. Afternoon RH remains critically dry with values between
15 and 30 percent, with far southern portions of the interior
Central Coast potentially seeing min RH near 10 percent. Energy
Release Components (ERC) are projected to climb above the 97th
percentile across the interior Central Coast. 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 1216 PM PDT Thu Jul 30 2026
Long period southerly to southwesterly swell of 14-17 seconds
continues to impact our coastline through at least Saturday
afternoon, bringing hazardous beach conditions to the Central
Coast and the San Francisco Bay Area. Sneaker waves and strong rip
currents will be the primary threats, with breaking waves up to
10 feet along some south and southwest facing beaches and break
points, such as 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, resulting in people
and pets being swept into the cold, turbulent ocean. Rip currents
are strong enough to pull even the strongest swimmers away from
shore. Check marine conditions before you head out! Swim near a
lifeguard, if possible. Maintain a safe distance from the water,
and stay 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.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Saturday 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 Saturday for Pt Arena to Pt
Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.
Gale Warning from 9 AM to 3 PM PDT Saturday for Pt Arena to Pt
Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory until 9 PM PDT this evening for Pt Reyes to
Pigeon Pt 0-10 nm.
Small Craft Advisory from 3 PM Friday to 3 PM PDT Saturday for
Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory until 9 PM PDT Friday for Pigeon Pt to Pt
Pinos 0-10 nm.
Small Craft Advisory from 9 AM to 3 PM PDT Saturday for Pigeon
Pt to Pt Pinos 0-10 nm.
Small Craft Advisory until 3 PM PDT Saturday for Pigeon Pt to Pt
Pinos 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.
&&
$$
SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Navarrete
MARINE...Navarrete
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Prepared by Boulder-Creek.com Weather at: Thu Jul 30 12:30:02 PDT 2026
From the National Weather Service
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