FXUS66 KMTR 281925
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1225 PM PDT Tue Apr 28 2026

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

.KEY MESSAGES...
Updated at 1222 PM PDT Tue Apr 28 2026

 - Overnight and early morning stratus returns to the forecast

 - Warming and drying trend continues into the late week for 
   areas away from the coast

 - Cooler conditions return this weekend with a chance of drizzle
   and/or light rain into early next week 

&&

.SHORT TERM...
Issued at 1222 PM PDT Tue Apr 28 2026
(This evening through Wednesday)

Temperatures this afternoon will warm into the upper 50s to mid 60s 
near the coast and the interior reaching into the mid 60s to lower 
70s under mostly sunny sky conditions. These temperatures are 
slightly below seasonal averages, generally up to 5 deg F cooler and 
up to 15 deg F cooler in the higher terrain. This is as a short-wave 
trough lingers over the Bay Area and northern Central Coast. 

Expecting low clouds to return to the coast and locally inland into 
the coastal adjacent valleys overnight tonight and more so into 
Wednesday morning. There is a greater probability of this to occur as 
the marine layer is forecast to deepen overnight to around 1,000 
feet. 

On Wednesday, as low clouds gradually retreat to the coast, 
temperatures rebound to near or slightly above (up to 5 deg F) 
seasonal averages. However, cooler temperatures will persist in the 
higher elevations. This is as high pressure begins to build eastward 
from the eastern Pacific. 

&&

.LONG TERM...
Issued at 1222 PM PDT Tue Apr 28 2026
(Wednesday night through next Monday)

The warming trend will continue into late week with interior 
temperatures up to 10 deg F above normal by Friday as the 
aforementioned ridge builds overhead. Friday is when we have the 
greatest probability of reaching or exceeding 85 deg F across the 
interior, with the warmest being across the interior Central Coast 
(greater than 50%). However, the marine layer will remain in place 
and keep temperatures cooler near the coast. This is as the ebb and 
flow of late evening and overnight stratus returns to the coast and 
coastal adjacent valleys each day. 

A slight cooling trend is forecast to return on Saturday as a 
mid/upper level low drops southward out of the Gulf of Alaska. This 
low pressure system will eventually become a cut-off low with high 
pressure building across British Columbia late in the upcoming 
weekend setting up a Rex block. This would bring drizzle and/or 
light rain to the coastal waters Saturday night and into Sunday. 
Then, as the mid/upper level low shifts inland Monday and Tuesday, 
it will bring increasing chances for drizzle and/or light rain to 
the Bay Area and Central Coast. Rainfall amounts from this system 
are expected to remain light, however they will make for wet 
roadways across the region. 

&&

.AVIATION...
(18Z TAFS)
Issued at 1015 AM PDT Tue Apr 28 2026

The morning low clouds were much more scattered than I thought 
they would be at this time yesterday. There is still enough
instability in the lower atmosphere to stay well mixed. In fact,
we are starting to see some fair weather cumulus clouds pop up 
over the southern hills as the surface temperatures warm and take 
advantage of this instability. That being said, these midday 
clouds are not expected to bring significant impacts to the TAF 
sites, and there is high confidence in widespread VMC through 
through day. Clouds will start to roll in again overnight, but the
coverage will again be spotty. High resolution models are pretty 
confident that the North Bay will stay clear of stratus, but that 
opens the possibility for radiation fog. The rest of the Bay Area 
has a decent chance for MVFR impacts as the marine layer gradually
works to gain some structure overnight.

Vicinity of SFO...Relatively standard conditions today with clear
skies and moderate onshore winds in the afternoon. The challenging
part of the forecast is tomorrow morning. There is a 6 hour window
between 12Z and 18Z where there is a 30-50% chance of MVFR impacts
over the terminal. As we saw this morning (OAK developed a 
ceiling for 6 hours, while SFO only had it for 30 mins) the 
stratus deck doesn't look very healthy tomorrow and the forecast 
confidence is quite low.

SFO Bridge Approach...Similar to SFO

Monterey Bay Terminals...After a clear afternoon, the southern 
terminals have the best chance for both MVFR and IFR impacts
overnight due to a more compressed boundary layer and better 
onshore flow. The high res models are fairly confident, but the 
persistence forecast is more optimistic, so it's not a slam dunk.

&&

.MARINE...
(Today through Sunday)
Issued at 818 AM PDT Tue Apr 28 2026

The gradient between high pressure over the Eastern Pacific and
low pressure over California will build over the next few days,
generating a strong NW breeze from Wednesday through Friday. These
winds will build rough seas of 8-12 feet across exposed waters.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM Wednesday to 3 AM PDT Thursday 
     for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 
     nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 9 AM PDT Thursday for Pt Arena to Pt 
     Reyes 10-60 NM.

     Small Craft Advisory from 3 PM Wednesday to 9 AM PDT Thursday 
     for Pigeon Pt to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Flynn
MARINE...Flynn

Visit us at www.weather.gov/sanfrancisco

Follow us on Facebook, X, and YouTube at:
www.facebook.com/nwsbayarea
x.com/nwsbayarea
www.youtube.com/nwsbayarea


  
Prepared by Boulder-Creek.com Weather at: Tue Apr 28 16:30:03 PDT 2026