FXUS66 KMTR 162014
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
114 PM PDT Thu Apr 16 2026

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

.KEY MESSAGES...
Updated at 112 PM PDT Thu Apr 16 2026

 - Periods of gusty offshore winds, especially at higher
   elevations, continue through early Friday morning

 - Seasonably warm temperatures expected Friday and Saturday

 - Cooler temperatures and beneficial rain Sunday into early next
   week

&&

.SHORT TERM...
Issued at 112 PM PDT Thu Apr 16 2026
(This evening through Friday)

Gusty offshore winds continue across the higher terrain through late 
Friday morning as a deep upper level trough pushes into the Northern 
Rockies. The strongest gusts are expected across the Vaca Range and 
the Mayacamas Range in Sonoma and Napa Counties respectfully. Winds 
shifted offshore (north to northeast) early this morning with Mt. 
St. Helena reporting a peak gust of 58 mph at 9:30AM this morning. 
Outside of the highest peaks (including Mt. St. Helena), gusts are 
expected to peak between 35 to 45 mph with locally stronger gusts 
across the highest peaks/ridgelines. Winds ease slightly this 
afternoon/evening before restrengthening tonight into Friday 
morning. By late Friday morning, winds will diminish across the 
higher elevations as the deep upper level trough progresses eastward 
and ridging builds over the West Coast. Very dry daytime conditions 
continue across the interior today and tomorrow due to the moderate 
offshore winds. Overnight humidity recoveries will be good along the 
coast but poor across the interior higher terrain (where gusty 
winds continue throughout the night). Fire concerns remain minimal
thanks to the recent wetting rains and the upcoming wetting rains
next week. 

Seasonal high temperatures in the 60s to low 70s continue across the 
interior while highs in the 50s to 60s prevail along the coast. 
Friday morning continues to look chilly as clear skies overnight 
will lead to increased radiational cooling. Much of the region will 
see low temperatures in the 40s on Friday while portions of the 
eastern Santa Clara Hills and the interior Central Coast drop into 
the 30s. Residents in the vicinity of Parkfield and Bradley 
(Monterey County) will see temperatures drop into the low 30s. By 
the afternoon, chilly temperatures will be a distant memory with 
highs rising back into the low to mid 70s across the interior and 
50s to 60s along the coast. This slight warming trend will continue 
into Saturday as upper level ridging rebuilds over the West Coast.

&&

.LONG TERM...
Issued at 112 PM PDT Thu Apr 16 2026
(Friday night through next Wednesday)

Seasonably warm temperatures continue into Saturday as upper level 
ridging builds. Interior highs will peak in the mid to upper 70s 
with coastal areas staying in the 60s. Temperatures start to cool 
Sunday as the ridge progresses east with seasonal temperatures in 
the 60s to low 70s expected across most of the region. Seasonably 
warm temperatures continue for one more day across the interior 
Central Coast where highs linger in the mid to upper 70s. As the 
ridge exits, a deep upper level trough will push into the West Coast 
with an associated weak surface low and cold front. Model guidance 
is still split as to when the trough will arrive. The GFS favors a 
slower arrival (more so Monday-Tuesday) whereas the ECMWF favors a 
slightly faster arrival late Sunday into Monday. In terms of 
ensemble cluster guidance, three of the five clusters support a 
stronger low that lingers offshore of California Sunday through 
Tuesday. The other two clusters support a more progressive low that 
moves inland faster.  If the cut-off low lingers offshore, rather 
than progressing inland, that may allow the storm to overperform 
slightly and see higher amounts of rain across the region. 
Thunderstorms are also possible Monday and Tuesday afternoons with 
around a 10-20% chance of thunderstorms on Tuesday. Guidance shows a 
few hundred joules of MUCAPE with decent lift and moisture from the 
low. Models are showing early potential for a NCFR to develop on 
Tuesday which will be interesting to see how it evolves as this 
system gets closer in time. Rainfall totals from this event are 
still beneficial with around 1.5-2.5" expected across the North Bay, 
1-2" across the coastal mountain ranges, and 0.5-1.0" across the 
lower elevations. Locally gusty onshore winds are expected Monday 
into Tuesday along the coast and across the higher elevations but 
winds are forecast to stay below Wind Advisory criteria. 
Temperatures drop into the 60s across the region starting Monday and 
remain there through midweek while morning lows remain in the 40s to 
low 50s.

&&

.AVIATION...
(18Z TAFS)
Issued at 1201 PM PDT Thu Apr 16 2026
VFR conditions are expected through the forecast period, with the 
highlight being increasing offshore flow. These winds have 
already picked up over the North Bay earlier this morning and are 
being observed across much of the region. When winds pick up later
this evening and into the overnight hours, the threat for low 
level wind shear increases over the North Bay and Bay Area 
terminals. The most likely terminals to see LLWS will be KAPC, 
KSTS, and KLVK with a bit more uncertainty for KSFO, KOAK, and 
KSJC. For LVK, there is some uncertainty regarding the exact wind
direction around 03Z which is associated with the onset of the 
low level wind shear. Model guidance is showing some component of 
southerly flow combined with northerly wind gusts. The exact 
timing of the persistent southwesterly winds is uncertain and may 
occur earlier than 08Z. LLWS chances begin to ease for most sites 
between 10-13Z as winds ease overall. 

Vicinity of SFO...

SFO Bridge Approach...Winds around SFO this morning are generally from 
the N to NE, but should return to the NW over the next couple of 
hours. Wind speed should increase to roughly 10-15kt, with the 
possibility of gusts to 25-30kt after 21Z and continue through 
sunset. Onshore winds should begin to ease then, with offshore winds 
returning between 6Z-9Z and holding through the overnight hours. 
Looking at soundings around KSFO, there is the possibility for LLWS. 
opted to adjust the TAF slightly and cap it around 30kt rather than 
40kt given the uncertainty of how strong the northerly winds will 
be. Any threat of wind shear should ease just before or around 
sunrise, as winds ease. Onshore flow returns tomorrow afternoon. 

Monterey Bay Terminals... 
At SNS, there is uncertainty regarding the exact timing on the 
return of offshore winds after 10Z. It may return in the later end 
of the TAF period, but model guidance is not consistent at this 
time. Will update as needed. Aside from that, expect VFR conditions. 
There will be a break from the moderate winds through the night 
before picking up again early morning tomorrow.

&&

.MARINE...
(Today through Tuesday)
Issued at 433 AM PDT Thu Apr 16 2026

A weak cold front will sweep across the coastal waters early this
morning. The passing front will bring fresh to near gale breezes
to the coastal waters and bays through today. These winds will
build rough seas of 10-12 feet across the outer coastal waters.
Winds will ease back to moderate northwest breezes Friday through
Saturday, allowing seas to gradually subside.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay.

     Small Craft Advisory until 9 PM PDT this evening 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 3 AM PDT Friday for Pigeon Pt to Pt 
     Pinos 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Gale Warning until 9 PM PDT this evening for Pt Arena to Pt 
     Reyes 10-60 NM.

&&

$$

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

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Prepared by Boulder-Creek.com Weather at: Thu Apr 16 14:30:02 PDT 2026