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NWS Technical
Weather Discussion |
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FXUS66 KMTR 142006
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
106 PM PDT Tue Jul 14 2026
...New SHORT TERM, LONG TERM, FIRE WEATHER...
.KEY MESSAGES...
Updated at 101 PM PDT Tue Jul 14 2026
- Moderate HeatRisk across the interior through Wednesday
- Breezy onshore winds today through Thursday afternoon
- Minor coastal flooding continues through Thursday due to large
tidal swings
&&
.SHORT TERM...
Issued at 101 PM PDT Tue Jul 14 2026
(This evening through Wednesday night)
This afternoon is forecast to be the warmest of the week with
temperatures across the interior peaking in the middle 90s up to
around 103 deg F. As such, we have a Heat Advisory out for most of
the interior through 10 PM tonight where we have Moderate
HeatRisk forecasted. Near the coast, temperatures will be
moderated by the afternoon sea breeze (yet up to 6 degrees above
average given the lack of a stratus deck). That said, very dry
conditions (especially in the higher terrain) will persist through
midweek as high pressure over the Rockies and Midwest persists.
Please see the Fire Weather section of the AFD for more
information.
Tonight, expecting mostly clear sky conditions across the region
and temperatures near the coast and in the valleys to be in the
60s. However, some guidance suggests the North Bay coast and
adjacent valleys and locations along the immediate coastline
across the entire region will cool into the 50s with better
radiational cooling given the lack of high cloud cover.
How much cooling that occurs overnight into Wednesday morning
will likely dictate how warm tomorrow will be to some extend. We
again continue to have a Heat Advisory in effect for the Santa
Lucia Rage, Los Padres National Forest, and the southern Salinas
Valley from 10 AM - 10 PM Wednesday where the most widespread
Moderate HeatRisk exists. Elsewhere, temperatures continue on a
downward trend for Wednesday (still above seasonal averages
however).
&&
.LONG TERM...
Issued at 101 PM PDT Tue Jul 14 2026
(Thursday through next Monday)
A mid/upper level trough just off of the Pacific Northwest coast
will deepen slightly late in the week, bring temperatures closer
to seasonal averages as onshore flow increases. This will also
bring Minor HeatRisk to just about all of the region Thursday and
beyond. As a result of increased onshore winds, the marine layer
is forecast to deepen to around 1,000 feet in depth.
From the previous forecaster: "At 500 mb the high pressure over the
Rockies will remain in place as the trough approaches the coast.
This pattern will keep mid-level winds out of the south to southwest
through the week. That means the tropical moisture conveyer belt
will remain open. While dry air will dominate the middle of the
week, there is an increasing chance that one of the many robust
tropical waves off the coast of Mexico will develop into a tropical
cyclone this week aided by the warm El Nino waters. If that happens,
there is a chance that some of the associated moisture will be drawn
into the SW winds and advect over the Bay Area, bringing us similar
impacts and considerations that we saw with recent monsoon moisture
event. Depending on the strength of the TC, there could also be
impacts from ocean swell at the beach. The uncertainty is still
high, but it's been trending more likely recently. The ECMWF 50
member ensemble has a mean PW returning above 1.0" by Sunday-
Monday. That's around the 90th percentile for this time of year. I
also noticed 7 of the members have a PW over 1.5", and 2 members are
over 2". The highest we've ever recorded is 1.79", and that was on
8/16/2020, when the remnants of Tropical Storm Fausto brought a
major dry lightning outbreak to the Bay Area and sparked several
wildfires. I'm certainly not predicting a repeat of August 2020, but
it's worth keeping an eye on this next potential moisture push given
the current warm temperatures and dry fuels."
&&
.AVIATION...
(18Z TAFS)
Issued at 1129 AM PDT Tue Jul 14 2026
Mainly clear skies and VFR conditions are expected for the TAF cycle
as the monsoon moisture exits the region. Winds will gradually
become onshore throughout the day. Very few hi-res models show low
clouds trying to develop late tonight and into Wednesday morning.
The signs for stratus development increase Wednesday night into,
with Thursday into Friday looking even better.
Vicinity of SFO...VFR conditions will prevail with the main story
being increasing onshore flow this afternoon and evening. Winds will
pick up between 19-21Z and then hold through roughly 03-4Z before
gradually decreasing. Sustained speeds will range from 12-18kt and
gusts may reach 25kt at times during this time frame. Wednesday
afternoon, the onshore push looks to be a bit stronger and roughly
around the same time frame. Gusts up to 25kt are expected, but may
get to 30kt for a few hours during the late afternoon and early
evening.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Light winds, clear skies, and VFR
conditions will prevail. A few models try to hint at the marine
layer making a return tonight; however, confidence is low in that
occuring. The signs for stratus development increase Wednesday night
into, with Thursday into Friday looking even better.
&&
.MARINE...
(Today through Sunday)
Issued at 1129 AM PDT Tue Jul 14 2026
Moderate to fresh northwesterly breezes are expected through
Wednesday leading to hazardous conditions for small craft will
result across the northern waters and along the Big Sur Coast.
Northwesterly breezes will increase on Thursday to become fresh to
strong, bringing widespread hazardous conditions for small craft.
Moderate seas will prevail, building to become rough in the outer
waters over the weekend.
&&
.FIRE WEATHER...
Issued at 101 PM PDT Tue Jul 14 2026
The warm temperatures we have had the past several days and
continued warm weather has resulted in fuels rapidly drying this
week. ERC charts are expected to exceed the 97th percentile across
the Mid Coast to Mendocino zone and get close to the 97th
percentile across the Central Coast. Fire weather concerns will
remain elevated this afternoon through Thursday due to near
critically dry conditions, gusty onshore winds, and very dry fuel
conditions. This may result in additional fire starts particularly
across the interior and higher elevations. Unsettled weather is
possible next weekend with returning potential for dry
thunderstorms and gusty, erratic winds.
RGass/Flynn
&&
.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 CAZ503-504-506-
510-513>517-528.
Coastal Flood Advisory until 4 AM PDT Wednesday for CAZ505-509-
529-530.
Heat Advisory from 10 AM to 10 PM PDT Wednesday for CAZ516-517.
PZ...Small Craft Advisory until 3 PM PDT Wednesday for Pt Arena to Pt
Reyes 0-10 nm.
Small Craft Advisory from 9 PM this evening to 9 AM PDT
Wednesday for Pt Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory until 3 PM PDT Wednesday for Pt Arena to Pt
Reyes 10-60 NM.
&&
$$
SHORT TERM...RGass
LONG TERM....RGass/Flynn
AVIATION...KR
MARINE...KR
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Prepared by Boulder-Creek.com Weather at: Tue Jul 14 16:30:03 PDT 2026
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From the National Weather
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Revised:
29 Mar 2008 09:53 -0800 GMT
(Pacific) |
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