FXUS66 KMTR 141756
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1056 AM PDT Wed Oct 14 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1216 AM PDT Wed Oct 14 2026
- Warming trend continues through the end of the work week with
above normal temperatures peaking Friday
- Coastal Flooding Advisory remains in effect through 4 PM today
for bayshore locations along the San Pablo Bay
- Elevated fire weather conditions due to moderate offshore flow
and very dry conditions across the higher elevations mid to
late week
&&
.SHORT TERM...
Issued at 1216 AM PDT Wed Oct 14 2026
(Today and tonight)
Upper level troughing continues to progress eastward with ridging
building just to our west over the Pacific Ocean. The warming trend
becomes more noticeable on Wednesday as ridging starts to push
inland and becomes the dominate force across our region. High
temperatures will be more seasonable in the upper 70s to low 80s
across the interior and 60s along the coastline. Morning low
temperatures will remain slightly chillier in the 40s to 50s
Wednesday morning and Thursday morning. Temperatures continue to
warm on Thursday with highs reaching into the 80s to low 90s across
the interior (5-10 degrees above normal) and 60s to 70s along the
coast. Little to no cloud cover is expected overnight with upper
level ridging keeping the marine layer mixed out. This in turn is
creating much drier daytime and overnight conditions, particularly
across the higher elevations.
Our main concern for the upcoming week continues to be the potential
for multiple rounds of offshore winds in the overnight through late
morning hours with emphasis on the North Bay Interior Mountains. In
the short term, offshore winds are expected Tuesday night into
Wednesday but they are expected to be weaker than what is expected
Thursday into Friday. The SFO-WMC pressure gradient shows it peaking
around -3 to -4 mb overnight tonight into Wednesday. This is a
fairly weak gradient with offshore winds not anticipated to be too
strong tonight and gusts peak around 20 mph for the North Bay
Interior Mountains tonight. The story is a little different heading
into Wednesday. The SFO-WMC gradient initially starts out fairly
weak (-3 to -4 mb) but it looks to strengthen to -8 to -9 mb by late
Thursday morning. This indicates more moderate offshore winds are
likely across the North Bay Interior Mountains with gusts between 30
to 35 mph likely. Why the changeup? To explain, we go back to our
synoptic setup. As the trough exits to our east, a part of it splits
off from the jet stream and becomes a cut-off low that gradually
retrogrades back towards the Desert Southwest Wednesday night into
Thursday morning. As the cut-off low settles over Southern
California, it will force the upper level ridging over Northern
California to take on a more positive tilt (northeast to southwest
orientation) which is more conducive for offshore flow across the
region. The combination of strengthening offshore winds Thursday and
dry daytime/overnight conditions will result in elevated fire
weather concerns for the higher elevations with emphasis on the
North Bay Interior Mountains. Elevated fire weather concerns will
continue through Friday with further discussion in the Long Term.
&&
.LONG TERM...
Issued at 1216 AM PDT Wed Oct 14 2026
(Thursday through Tuesday)
Moderate offshore flow continues across the higher elevations
Thursday afternoon through Friday morning with the SFO-WMC
gradient peaking around -10 to -11 mb Thursday night into Friday
morning. The NAM suggests further strengthening to -12 to -13 mb
is possible which could support stronger gusts than outlined in
the short term (currently forecast peak gusts of 30 to 40 mph).
The driest conditions are expected overnight Thursday into Friday
with overnight RH recoveries only reaching 25-35% across the
highest elevations and daytime RH values dropping back into the
10s to 20s. Winds gradually diminish late morning into the
afternoon as the pressure gradient relaxes. Elevated fire weather
conditions continue for the higher elevations through Friday with
conditions improving as winds decrease. If you are participating
in any activity involving fire be very cautious and make sure
sparks/flames do not escape as fuels are incredibly dry and ready
to go.
High temperatures peak Friday in the 80s to low 90s with patches of
upper 90s across the higher elevations and southern Santa Clara
Valley. Temperatures cool slightly into the 80s by Saturday with
only a few hot spots reaching the low 90s as the ridge relaxes and
troughing becomes more dominant. The cut-off low will then merge
with the jet stream and result in widespread troughing across the
West Coast late weekend into early next week. As this trough pushes
inland it will bring us our first weak storm system of the season.
Initial guidance shows a weak cold front passing through California
early next week that will bring both a return of below normal
temperatures in the 60s to low 70s, a chance for light rain, and
gusty onshore winds. Fall mornings return as well with morning lows
dropping back into the 40s again late weekend into early next week.
Initial guidance suggests a more widespread potential for light rain
(up to a few tenths of an inch) early to mid next week. Onshore
winds ramp up along the coast and across mountain gaps/passes Sunday
into mid next week. The current forecast does not currently meet
Wind Advisory criteria but it is something to keep an eye on as this
system approaches given the stronger winds already associated with
it.
&&
.AVIATION...
(18Z TAFS)
Issued at 1055 AM PDT Wed Oct 14 2026
VFR conditions are forecast for much of the region through the
TAF period as high pressure builds in from the eastern Pacific. As
mentioned earlier, some of the high resolution models are showing
stratus developing late tonight and into Thursday morning, yet
mainly along the coast of the North Bay and San Francisco
Peninsula. Onshore winds are forecast to return by early afternoon
and prevail into the early evening before becoming light/variable
and then weak offshore early Thursday morning. Medium to high
confidence for inland and low to moderate for coastal sites.
Vicinity of SFO...VFR. Light/variable to offshore flow this
morning becoming onshore by early afternoon. Winds are forecast to
be west- northwest between 10-15kt before easing after sunset.
Weak offshore flow is forecast after sunrise before becoming
onshore by early Thursday afternoon.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR. Onshore winds have returned to MRY
while drainage (southeasterly) winds persist at SNS. Onshore flow
is expected by early afternoon at both terminals before easing
after sunset.
&&
.MARINE...
(Today through Monday)
Issued at 1055 AM PDT Wed Oct 14 2026
Seas will continue to subside through tonight with moderate seas
expected for the offshore zones through the week while nearshore
waters observe moderate to slight seas. During this time frame
gentle to fresh northerly breezes persist. Moderate to fresh
northerly winds return for the weekend, which should lead to rough
seas.
&&
.FIRE WEATHER...
Issued at 502 AM PDT Wed Oct 14 2026
Elevated to near critical fire weather conditions are expected for
the higher elevations late tonight through Friday morning. The main
areas of concern will be for the North Bay Interior Mountains and
East Bay Hills. The strongest winds look to be over the North Bay
Interior Mountains where gusts 30-40 mph are possible, perhaps up to
45mph or higher for the highest elevations. The East Bay Hills will
be breezy as well, but may be closer to 25-35 mph with locally
higher gust for exposed ridges and areas of higher terrain. Both
areas will be dry with poor overnight RH recovery, which combined
with the breezy winds, warmer weather, and available fuels leads to
the elevated to near critical fire weather conditions.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until 4 PM PDT this afternoon for CAZ506.
PZ...None.
&&
$$
SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...RGass
MARINE...RGass
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: Wed Oct 14 12:30:03 PDT 2026
From the National Weather Service
|