FXUS66 KMTR 272130
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
230 PM PDT Mon Jul 27 2026

...New SHORT TERM, LONG TERM...

.KEY MESSAGES...
Updated at 216 PM PDT Mon Jul 27 2026

- Breezy onshore winds expected each afternoon and evening through
  early midweek

- Gradual warming starting midweek, with Moderate HeatRisk for
  interior locations

- 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 through the 
  end of the week

&&

.SHORT TERM...
Issued at 216 PM PDT Mon Jul 27 2026 
(This evening through Tuesday night)

Pleasant conditions persist this afternoon across the 
Bay Area and Central Coast. 24 hour tendencies in temperatures 
indicate most areas are running anywhere from 1-4 degrees lower than 
this time yesterday. While the stratus footprint has dwindled to 
the San Mateo coastline, persistent onshore flow is likely the 
culprit for the cooler conditions. As troughing continues on 
Tuesday, we'll contend with another period of onshore flow. 
There's some uncertainty with regard to the inland extent of 
marine stratus, but overall, mostly sunny skies are anticipated 
late morning and into the early afternoon on Tuesday. 

&&

.LONG TERM...
Issued at 216 PM PDT Mon Jul 27 2026 
(Wednesday through next Sunday)

Wednesday will be the start of our warming trend. The 
region will be on the backside of the aforementioned upper level 
trough with the Pacific Southwest Ridge projected to gradually 
expand westward Wednesday and into Thursday. While another compact 
upper level wave will move eastward onto the Oregon Coast late 
Thursday, it's impact on our weather seems to be an increase in
the winds over the marine environment thanks to the development 
of several coastal jet features. This, in theory, could help 
induce upwelling which may promote marine stratus development. 
However, forecast soundings from traditional NWP along with cross-
sections from the PG&E/SJSU WRF indicate the marine layer 
compressing to under 1000 feet (potentially lower through the end 
of the week). As such, infiltration of marine stratus should be 
limited spatially and at a minimal if at all. If stratus does 
develop, it'll likely dissipate rather quickly by mid to late 
morning. This promotes moderating temperatures, particularly 
across the interior and poor to moderate humidity recovery 
(30-50%) at elevation. More intel on this in the fire weather 
section below. 

Temperature wise, guidance remains in fair agreement with moderating 
conditions on Wednesday and into the weekend across the Bay Area 
and Central Coast. We still maintain some very diffuse troughing 
aloft on the synoptic scale, but the ridge expands more noticeably
Thursday and into the weekend. Confidence has increased that the 
ridge will expand sufficiently enough to compress the marine 
layer, particularly across the Central Coast where the areal 
extent of Moderate HeatRisk increases quickly. There's still a 
chance that current MaxT forecasts may need to be trended upward 
across interior sections, but likely only on the order of 1-3 
degrees. Across the Santa Lucia and Galiban Ranges, pockets of 
Major HeatRisk enter the forecast with some on Wednesday, but 
especially Thursday and into the weekend. Those recreating across 
this region should ensure they are adequately hydrated with plenty
of water and have access to shade. Moderate HeatRisk becomes most
expansive Thursday and into Friday across the remainder of the 
Central Coast and this is when the potential for more formal heat 
products increases.

While there's strong consensus for hot conditions across the 
interior, coastal regions, including the population centers, 
model forecasts exhibit a much more significant spread. For 
instance, the KSFO MaxT interquartile ranges from the mid-60s on 
the low end to low to mid-80s on the high end Thursday and into 
the weekend. What will likely modulate just how hot it gets for 
coastal locations will be onshore vs. offshore flow. 925mb flow in
the deterministic guidance starts to diminish especially Friday 
and into the weekend. As flow drops below 10 knots, there's the 
potential for a large degree of variability in direction and 
should a given location experience periods of either very weak 
onshore flow or offshore winds, MaxT will likely verify on the 
higher end of the spread. In the case of KSFO, mid-80s would be 
nearly 10-15 degrees warmer than normal. For now the forecast 
currently resides on the warmer end of things through at least 
Thursday, but additional adjustments will be made as we venture 
closer to mid- week. Regardless, it'll be important for those 
across the area to remain hydrated with plenty of water, stay cool
and limit strenuous outdoor activities to the cooler portions of 
the day. Never leave kids or pets unattended in vehicles! In 
addition, if headed to our Pacific coast beaches for relief, be 
mindful of the increased risk for sneaker waves and rip currents. 


&&

.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 152 PM PDT Mon Jul 27 2026

The elevated fire weather threat will persist across portions of
the area through mid-week. Overnight RH recovery will remain
moderate at locations at or above 2,000 feet with values around 40
to 50 percent. 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-dawn hours) may also
transpire which will increase the burn period or time in which 
fire behavior may remain active. Afternoon RH will remain 
critically dry with values between 20 and 40 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 95th 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 145 PM PDT Sun Jul 26 2026 

Distant tropical cyclones in the Eastern Pacific will continue to
generate 16-18 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. Breaking waves can reach up to 12 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. Hazardous beach conditions are anticipated to persist 
through Saturday afternoon.

&&

.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 from 2 PM to 9 PM PDT Tuesday for Mry Bay-
     SF Bay N of Bay Bridge.

     Small Craft Advisory until 3 AM PDT Wednesday 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...Bain
LONG TERM....Bain
AVIATION...Navarrete/Bain
MARINE...Navarrete
FIRE WEATHER...Bain
BEACHES...Navarrete

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Prepared by Boulder-Creek.com Weather at: Mon Jul 27 16:30:04 PDT 2026