Technical NOAA Weather Discussion

FXUS66 KMTR 152353
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
453 PM PDT Wed Jul 15 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 126 PM PDT Wed Jul 15 2026

 - Moderate HeatRisk continues across the interior today

 - Breezy onshore winds through Friday 

 - Elevated fire weather conditions through Thursday

&&

.SHORT TERM...
Issued at 138 PM PDT Wed Jul 15 2026
(This evening through Thursday night)

The marine layer is making a good attempt at returning! However, hot 
temperatures, very dry conditions, and breezy winds persist across 
the interior and higher terrain across the region this afternoon. 
With full sunshine, temperatures will warm into the 90s to 103 deg F 
(in the warmest interior spots). These temperatures are slightly 
cooler than yesterday, yet are up to 10 degrees above seasonal 
averages (up to 20 degrees above for the higher elevations). Cooler 
temperatures will persist near the coast as onshore winds prevail. 
The aforementioned hot, dry, and windy conditions are creating 
elevated fire weather conditions across the interior and higher 
terrain. Please see the Fire Weather Section of the AFD for more 
information.

The marine layer is forecast to deepen to around 500 feet tonight. 
However, cloud cover is a bit more uncertain. There is a 30-50% 
probability of stratus returning to the coastline and Monterey Bay 
during the overnight hours and into early Thursday morning. However, 
any low clouds that do develop will quickly dissipate by mid-to-late 
morning. 

For Thursday afternoon, temperatures generally cool to near seasonal 
averages for much of the region as onshore winds increase. This will 
lower HeatRisk to Minor category and bring an end to the warming 
trend as a mid/upper level trough of low pressure deepens off of the 
Pacific Northwest coast. Heading into Thursday night, the marine 
layer is forecast to deepen to around 1,000 feet and increase the 
potential for low clouds. 

&&

.LONG TERM...
Issued at 138 PM PDT Wed Jul 15 2026
(Friday through next Tuesday)

Onshore winds will persist through much of the upcoming weekend and 
will allow for the marine layer to deepen and remain steady at 
around 1,500 feet. Thus, expect temperatures to remain near to 
slightly below normal for mid July with stratus more likely into the 
weekend. These low clouds will retreat back to the coast by mid-to-
late morning. 

Heading into late weekend and early next week, we are keeping an eye 
on monsoon moisture working its way northward around the Southern 
Plains' mid/upper level high. However, latest trends indicate the 
focus for thunderstorms has shifted to the east over the Sierra 
Nevada Sunday into Monday. That said, still expecting mid-to-high 
level clouds over the region. This will need to be closely monitored 
over the coming days as any high based thunderstorms will likely 
result in dry lightning that can spark wildfires.

&&

.AVIATION...
(00Z TAFS)
Issued at 453 PM PDT Wed Jul 15 2026

VFR through the forecast except along the coast where low to 
moderate confidence in a late return of stratus tonight. Breezy 
winds continue through this evening before easing overnight. Winds 
generally stay out of the NW through the forecast period with the 
exception of the North Bay where winds are more southerly. Guidance 
indicates potential for stratus along the coast tonight but 
confidence is low to moderate. Satellite is currently clear so if 
any stratus is able to redevelop tonight it will be late and likely 
bring IFR to LIFR CIGs.

Vicinity of SFO...VFR. Winds out of the NW with gusts to around 30 
knots are expected this afternoon and again tomorrow afternoon. 
Guidance shows some potential for stratus to filter into the SF Bay 
tonight, potentially reaching SFO, but confidence is low.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR with low to moderate confidence in IFR 
conditions overnight. Breezy W to NW winds continue through this 
evening before diminishing overnight. Satellite is currently clear 
but models are indicating some potential for stratus to return 
tonight. If stratus does return it will be a late return (closer to 
10Z) with IFR to LIFR conditions possible.

&&

.MARINE...
(Tonight through next Monday)
Issued at 453 PM PDT Wed Jul 15 2026

Moderate to strong gusty wind across the coastal waters and  bays
will produce hazardous conditions for small crafts through  much
of the week. Gale force gusts are expected along the coastal  jet
regions of Point Reyes and Point Sur. Moderate to rough seas  will
prevail through Friday.

&&

.FIRE WEATHER...
Issued at 138 PM PDT Wed Jul 15 2026

The warm temperatures we have had the past several days and 
continued warm weather has resulted in fuels rapidly drying this 
week. Fire weather concerns will remain elevated this afternoon with 
afternoon relative humidity dropping to between 10-20% across the 
interior and higher elevations (away from the marine influences), 
gusty onshore winds, and very dry fuels. This may result in 
additional fire starts particularly across the interior and higher 
elevations. These conditions are gradually forecast to improve as 
the marine layer returns Thursday and deepens into Friday. Unsettled 
weather is possible late this weekend and into early next week with 
returning potential for dry thunderstorms and gusty, erratic winds. 
However, the focus has shift to the east more over the Sierra 
Nevada. 

RGass

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until 4 AM PDT Thursday for CAZ006-506-
     508.

     Heat Advisory until 10 PM PDT this evening for CAZ516-517.

PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay-SF 
     Bay N of Bay Bridge.

     Small Craft Advisory from 9 AM to 3 PM PDT Thursday for Mry Bay.

     Small Craft Advisory until 3 AM PDT Friday for Pigeon Pt to Pt 
     Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to 
     Pigeon Pt 0-10 nm.

     Small Craft Advisory until 9 AM PDT Thursday for Pt Pinos to Pt 
     Piedras Blancas 0-10 nm.

     Gale Warning from 9 AM to 8 PM PDT Thursday for Pt Pinos to Pt 
     Piedras Blancas 0-10 nm.

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

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Kennedy
MARINE...CW

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Prepared by Boulder-Creek.com Weather at: Wed Jul 15 18:30:03 PDT 2026
From the National Weather Service