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NWS Technical
Weather Discussion |
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FXUS66 KMTR 142000
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
100 PM PDT Thu May 14 2026
...New SHORT TERM, LONG TERM...
.KEY MESSAGES...
Updated at 1258 PM PDT Thu May 14 2026
- Breezy and gusty winds return Friday into the weekend
- Hazardous marine conditions expected Friday into the weekend
- Elevated fire weather conditions Friday through Monday across
the interior with low humidities and strong gusts
&&
.SHORT TERM...
Issued at 1258 PM PDT Thu May 14 2026
(This evening through Friday)
Clear skies and warm temperatures have set up across the region as
mild ridging comes over the state. High temperatures today and
Friday range from the upper 70s to the middle 80s across the inland
valleys, perhaps reaching the upper 80s in the warmest spots, the
upper 60s to the upper 70s along the Bays, and the upper 50s to
middle 60s along the Pacific coast. Some breezy northwest winds will
develop at the coast, along ridgelines, and through gaps and passes
with gusts up to around 25 mph, but this will be relatively mild
compared to the forecast for the next few days.
Friday will mark the start of a developing inside slider as an upper
level trough moves into the Pacific Northwest and starts to sharpen
the pressure gradient across northern California. Northwest winds
will strengthen across the region leading to gusts reaching 35 to 45
mph along the coast, across the ridgelines, and through favored gaps
and passes including the northern Salinas Valley; the rest of the
forecast area should expect to see gusts reaching 25 to 35 mph.
While favored coastal locations and ridgelines may reach Wind
Advisory criteria (gusts of 45 mph or above), I'm not seeing gusts
these strong over a wide enough region to issue one at this time.
Still, these strong winds could still loosen branches and lead to
difficult driving conditions for high profile vehicles and isolated
power outages, especially when combined with hazardous wind-driven
waves and blowing sand at the beach and elevated fire danger across
the interior. These winds will contribute to hazardous beach
conditions, notably large wind-driven waves and blowing sand. A
Beach Hazards Statement has just been issued from Friday through
Monday due to these risks. See the BEACHES and FIRE WEATHER sections
for more details.
&&
.LONG TERM...
Issued at 1258 PM PDT Thu May 14 2026
(Friday night through next Wednesday)
The inside slider begins in earnest over the weekend as the upper
level trough stalls out over eastern Washington on Saturday before
dipping into the Great Basin on Sunday. This turns the upper level
flow from a more zonal (west to east) pattern into a more meridional
(north to south) pattern, and although the upper level flow remains
just to the west of due north, it will be enough to cause the winds
to turn more to the north and for humidities to dip, especially in
the interior regions where daytime relative humidity values from 10
to 25% are possible on Sunday.
The track of the low will also maintain the tight pressure gradient
over central California and maintain strong gusts over the region.
In addition, there is the potential for the mixing down of stronger
gusts across the coastal regions over the weekend as a coastal jet
sets up. The strongest gusts are expected to begin Saturday through
Monday morning, with gusts of 45 to 55 mph possible at the coast,
along the interior ridgelines of the North and East Bay, and through
the northern Salinas Valley and Altamont Pass; these strong gusts
could result in isolated downed trees. Can't rule out a Wind
Advisory for the coastal regions and the adjacent mountains for the
weekend. By Monday afternoon, the upper level low will weaken and
pull away into the northern Rockies, allowing the pressure gradient
to slacken and a developing upper level ridge over the eastern
Pacific to begin influencing the weather pattern.
Temperatures on Saturday and Sunday will back into the 70s to lower
80s in the inland valleys before the warming trend resumes early
next week. With California sitting between the building ridge and
the lingering trough, high temperatures across the region are still
a little uncertain. After collaboration with our neighbors and
national centers, the raw NBM output, which continues to run a
little warm, was tamped down by as much as 3 to 5 degrees,
especially along the coastal regions. The general pattern will be
for highs in the 80s to the lower 90s inland, the middle 70s to the
middle 80s near the bays, and the 60s to lower 70s along the Pacific
coast. Towards and after the end of the 7-day outlook, the
uncertainty ramps up as the interaction between the ridge over the
Pacific and any troughing over the Rockies becomes more variable
within the ensemble space. As noted yesterday around this time, the
inland valleys could see highs varying by around 5 or 10 degrees
around the current forecasts, while coastal and bayshore regions
could see drastically different changes in the outlook, especially
if a marine layer influence returns to more of the region.
&&
.AVIATION...
(18Z TAFS)
Issued at 1101 AM PDT Thu May 14 2026
VFR. Onshore winds are forecast to increase by early afternoon
before diminishing late in the evening and overnight. The greatest
potential for sub-VFR conditions will be along coastal sites (HAF &
MRY) late this evening and into early Friday morning. Elsewhere,
high confidence of VFR conditions prevailing through the TAF period.
Onshore winds increase once again Friday afternoon.
Vicinity of SFO...VFR through the TAF period. High confidence of
onshore winds increasing this afternoon and will persist through
late evening before diminishing slightly overnight and into Friday
morning. Gusts are likely to exceed 30 kt this afternoon and into
early evening. Onshore winds will once again increase Friday
afternoon and evening.
SFO Bridge Approach...Weaker onshore winds this afternoon
compared to SFO. Otherwise, similar to SFO.
Monterey Bay Terminals...VFR. High confidence of onshore winds
increasing this afternoon and will persist through early evening
before diminishing into Friday morning. Moderate confidence for
sub- MVFR conditions to develop around 05Z at MRY late tonight and
potentially lower to LIFR around 09Z Friday with SNS a TEMPO
group from 12Z-16Z (IFR). Conditions are likely to return to VFR
by mid-to- late morning on Friday.
&&
.MARINE...
(Today through Tuesday)
Issued at 1101 AM PDT Thu May 14 2026
Hazardous marine conditions have become widespread with gale
force winds affecting the northern waters into Thursday afternoon.
Gale-force gusts winds become widespread Friday morning and
continue to gain strength over the weekend. Locally stronger gusts
will be possible along some of the coastal jets where storm force
winds will be possible. The strong winds will drive seas between
12 to 19 feet. Winds peak on Sunday and reduce steadily into the
next work week.
&&
.FIRE WEATHER...
Issued at 530 AM PDT Thu May 14 2026
Fire weather concerns increase in the late week. Gusty offshore
winds build on Friday and strengthen through the weekend with peak
gusts above 30 mph for most areas and around 40 to 50 mph along
the coast, through gaps and passes, and across the ridgelines.
Very low daytime humidities of 15-25% will prevail across the
interior regions and higher peaks, with reduced overnight humidity
recoveries. Strong winds persist into the early part of Monday
before diminishing, but humidities will be slow to recover as a
modest offshore flow continues into the work week.
&&
.BEACHES...
Issued at 1258 PM PDT Thu May 14 2026
A Beach Hazards Statement has just been issued for west facing
beaches along the Pacific Coast from 3 PM Friday through 9 AM
Monday due to strong winds over the marine environment leading to
hazardously strong wind waves and overall rough seas. Dangerous
swimming, boating, and surfing conditions can be expected. Large
breaking waves can overpower swimmers resulting in significant
physical injury and increase the risk of drowning. Gusts will stay
strong along the immediate coast, causing blowing and drifting
sand and increased sea spray. Water rescue attempts may be
hampered by reduced visibilities from the spray and sand.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement from Friday afternoon through Monday
morning for CAZ006-505-509-530.
PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay.
Small Craft Advisory from 9 AM Friday to 3 PM PDT Saturday for
Mry Bay.
Gale Warning from 3 PM Saturday to 9 PM PDT Sunday for Mry Bay.
Small Craft Advisory until 3 PM PDT this afternoon for Pigeon Pt
to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena
to Pt Reyes 10-60 NM.
Gale Warning until 9 PM PDT Sunday for Pigeon Pt to Pt Pinos 10-
60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-
60 NM.
Small Craft Advisory until 9 PM PDT this evening for Pt Reyes to
Pigeon Pt 0-10 nm.
Gale Warning from 9 PM this evening to 9 PM PDT Sunday for Pt
Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory until 3 PM PDT Friday for Pigeon Pt to Pt
Pinos 0-10 nm.
Gale Warning from 3 PM Friday to 9 PM PDT Sunday for Pigeon Pt
to Pt Pinos 0-10 nm.
Small Craft Advisory until 3 AM PDT Friday for Pt Pinos to Pt
Piedras Blancas 0-10 nm.
Gale Warning from 3 AM Friday to 9 AM PDT Saturday for Pt Pinos
to Pt Piedras Blancas 0-10 nm.
Storm Watch from Saturday morning through Sunday evening for Pt
Pinos to Pt Piedras Blancas 0-10 nm.
&&
$$
SHORT TERM...DialH
LONG TERM....DialH
AVIATION...RGass
MARINE...RGass
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Prepared by Boulder-Creek.com Weather at: Thu May 14 14:30:03 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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