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NWS Technical
Weather Discussion |
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FXUS66 KMTR 180453
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
953 PM PDT Fri Apr 17 2026
...New AVIATION, MARINE...
.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...
(06Z TAFS)
Issued at 953 PM PDT Fri Apr 17 2026
Breezy onshore winds are diminishing across much of the region with
only relatively breezy conditions continuing at SFO. Winds remain on
track to continue diminishing overnight and become variable. LAMP
guidance continues to indicate stratus is possible at HAF but
confidence remains low. If stratus were to develop at HAF it would
likely be short lived between 12Z-18Z. Elsewhere, VFR conditions
prevail through the remainder of the TAF period. Stratus looks to
return shortly after 06Z Sunday.
Vicinity of SFO...VFR. Breezy onshore winds continue to diminish
tonight before becoming variable through tomorrow morning. Winds
restrengthen during the afternoon/evening with winds around 15 knots
expected. Some potential for stratus to return towards the end of
the TAF period but confidence is currently lower.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR. Light, variable winds continue
overnight with breezy onshore winds redeveloping during the
afternoon/evening. Winds peak between 10 to 13 knots.&&
.MARINE...
(Tonight through next Thursday)
Issued at 953 PM PDT Fri Apr 17 2026
Fresh north to northwest winds will continue to diminish through
Saturday with moderate winds expected Saturday afternoon into
Sunday. Winds shift southerly Sunday ahead of an incoming low
pressure system and cold front. Winds are expected to strengthen
ahead of cold frontal passage Monday into Tuesday with localized
strong gusts expected. Moderate seas, rain, and a slight chance of
thunderstorms Monday and Tuesday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Kennedy
MARINE...Kennedy
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Prepared by Boulder-Creek.com Weather at: Fri Apr 17 22:30:02 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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