FXUS66 KMTR 172349
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
449 PM PDT Fri Apr 17 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 1148 AM PDT Fri Apr 17 2026

 - Seasonably warm temperatures expected through the weekend

 - Cooler temperatures and beneficial rain for the beginning of 
   next week

&&

.SHORT TERM...
Issued at 1148 AM PDT Fri Apr 17 2026
(This afternoon through Saturday)

Gusty offshore winds prevail across the Vaca Range, Mayacamas 
Range, and higher elevations of the East Bay Hills (such as Mt. 
Diablo). However, as the day progresses, wind speeds will 
gradually diminish as high pressure builds in from the eastern 
Pacific. Thus, a gradual warming trend will continue today with 
temperatures reaching the mid 60s to low 70s across the interior 
(potentially mid 70s in the warmest interior locations).

Overnight, temperatures will be chilly and lower into the 40s 
across most of the lower elevations and near 50 degrees F closer 
to the coast. However, these temperatures are near seasonal 
averages. High clouds are forecast to stream in from the west 
during the overnight hours. 

These high clouds will persist into Saturday when we are 
forecasting the warmest temperatures of the weekend to occur. This
is as the mid/upper level short wave ridge axis will become 
positioned over much of the Bay Area and Central Coast. There is a
greater than 50% probability for San Jose, Gilroy, Hollister, and
King City to exceed 80 degrees F on Saturday afternoon (but near 
0% of exceeding 85 degrees F). Elsewhere, we are expecting mid-to-
upper 60s on northwest facing coastal locations and low-to-upper 
70s across the rest of the region. 

&&

.LONG TERM...
Issued at 1148 AM PDT Fri Apr 17 2026
(Saturday night through next Thursday)

A gradual cooling trend will begin on Sunday as a mid/upper level
low drops out of the Gulf of Alaska and approaches the Pacific 
Northwest and northern California coast. This will bring unsettled
weather to much of the region Monday and Tuesday with 
temperatures dropping to below seasonal averages. Rain chances 
begin across the North Bay late Sunday, yet rainfall amounts will 
generally be light (if any occurs). There are still differences in
the deterministic models with the ECMWF bringing rain to the 
North Bay late Sunday while the GFS does not bring widespread 
precipitation in until Monday afternoon and evening. Southerly 
winds will also increase ahead of and along the frontal boundary, 
yet how strong they will be remains in question. Tuesday will be 
when the Bay Area and Central Coast will have the greatest 
potential for scattered showers and possible thunderstorms. We 
will have a better handle on the evolution of this system once we 
get in the range of the high resolution and convection-allowing 
models. Post-frontal rain showers look to linger into Wednesday. 
There still is no clear signal of what the pattern looks like 
heading into late next week.

&&

.AVIATION...
(00Z TAFS)
Issued at 449 PM PDT Fri Apr 17 2026

VFR through the TAF period. HREF shows some potential for low level 
clouds to impact HAF overnight but confidence was too low to include 
in TAF. Gusty onshore winds continue through this evening before 
diminishing overnight and becoming variable. Breezy onshore winds 
return again tomorrow afternoon with most sites seeing winds between 
10-15 knots.

Vicinity of SFO...VFR. Gusty onshore winds continue through this 
evening before diminishing and becoming variable overnight. Winds 
look to restrengthen around 21Z and continue through the late 
evening. Winds may reduce as early as 05/06Z tomorrow night but 
confidence was too low to include in current TAF.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR. Breezy onshore winds continue through 
this evening before diminishing overnight. There is some potential 
for moderate SE winds at SNS early tomorrow morning before winds 
shift NW and strengthen during the afternoon/evening for both MRY 
and SNS.

&&

.MARINE...
(Tonight through next Wednesday)
Issued at 252 PM PDT Fri Apr 17 2026

Fresh northwest winds will continue to decrease through Saturday,
allowing seas to subside as well. On Sunday winds will shift to
the south ahead of a Pacific low pressure system that will bring
rain to the area beginning early next week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&

$$

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

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