Cupertino, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

489
FXUS66 KMTR 090802
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
102 AM PDT Wed Jul 9 2025

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

.KEY MESSAGES...
Updated at 101 AM PDT Wed Jul 9 2025

 - Warming trend begins today through the weekend, with patchy
   Moderate HeatRisk across the Bay Area and Central Coast
   Thursday and Friday.

 - Localized elevated fire weather threat starting today through
   the weekend across the higher elevations.

&&

.SHORT TERM...
Issued at 101 AM PDT Wed Jul 9 2025
(Today and tonight)

Satellite imagery shows widespread marine layer stratus across the
valleys of the Bay Area and Central Coast, as data from the Fort Ord
profiler shows the top of the marine layer becoming more diffuse
while rising to at least 3000 feet over the last evening. Low
temperatures this morning will hover in the lower to middle 50s in
the lower elevations, and as high as the lower 60s in the highest
peaks.

Today marks a pattern change from the cooler regime of the last few
days to a warming pattern that (spoiler alert) looks to set up for
the rest of the week. The upper level low that brought us the robust
marine layer and the cool temperatures is dissipating while it
meanders towards landfall in the North Coast. This will allow an
ridge that`s set up over the desert Southwest to edge into the state
while a synoptic high pressure system develops in the east Pacific,
causing temperatures to warm. Temperatures will range from the upper
70s to the middle 80s inland, with the warmest spots in southern
Monterey and San Benito Counties reaching the upper 90s, while
locations on the Bays reach highs in the upper 60s and the 70s. The
marine layer will compress, but the coastal areas should remain
rather cool with highs in the upper 50s to the lower 60s.

Some elevated fire weather threat is forecast to develop today
across areas above and inland of the marine layer`s influence. The
combination of dry daytime humidities of around 15-30% and localized
gusts to 30 mp will be the main factors behind the elevated threat.
However, the winds will remain onshore, leading to the fire weather
threat being diurnally driven, especially in the foothills where
lighter winds and good overnight recoveries are expected each
night.

&&

.LONG TERM...
Issued at 101 AM PDT Wed Jul 9 2025
(Thursday through Tuesday)

Temperatures continue to rise on Thursday and Friday as the high
pressure systems become more established, with the inland valleys
seeing highs in the middle 80s to middle 90s on both days, while the
warmest interior locations see temperatures rising up to a few
degrees above 100. Patches of Moderate HeatRisk are expected on
Thursday and Friday across the interior North Bay, East Bay, and
South Bay, in addition to the Santa Lucia mountains and the southern
tip of San Benito County. Remember to take frequent cooling breaks
and drink plenty of water if participating in outdoor activities on
both days.

As a very weak upper level disturbance passes through the state this
weekend, temperatures will cool slightly to the lower 80s to lower
90s in the interior Bay Area with an shortwave trough coming through
the West Coast, while the interior Central Coast remains rather warm
with temperatures in the 90s. The pattern will otherwise remain
rather stable through the early part of next week, with warm inland
temperatures, cool coastal temperatures, light onshore winds, and
localized elevated fire weather threat in the interior developing
each afternoon.

&&

.AVIATION...
(06Z TAFS)
Issued at 1002 PM PDT Tue Jul 8 2025

IFR and MVFR CIGS are building along the coast and have filled at
HAF as well as the SF Bay And Monterey Bay terminals. Winds will
stay light to moderate through the night as widespread IFR CIGs
affect the region with MRY and HAF falling to LIFR into the early
morning. Inland clearing begins in the mid morning with most TAF
sites going VFR in the late morning and early afternoon. The
exception will be HAF, which keeps CIGs through the TAF period.
Winds look to stay light to moderate through the morning and
increase into late Wednesday morning and afternoon. Expect winds
to reduce into Wednesday evening with CIGs slower to move inland
that night.

Vicinity of SFO...IFR lasts into the late morning. Winds are
reducing and look to stay light through the night and much of the
morning. Expect CIGs to  erode into the late morning as moderate
to breezy west winds arrive. These winds reduce into late
Wednesday evening.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR CIGs have filled over the terminals
and winds are reducing, becoming light. MRY sees winds become
very light into the night and CIGs fall to LIFR with some pockets
of mist and drizzle in the area into early Wednesday. Winds
become moderate into mid to late Wednesday morning as CIGs erode
over the terminals.

&&

.MARINE...
(Tonight through next Monday)
Issued at 900 PM PDT Tue Jul 8 2025

Expect light to moderate winds with weak seas into Wednesday.
Winds will strengthen and turn more northerly by Wednesday
afternoon and continue strengthening, becoming fresh to strong on
Thursday and into the weekend. Significant wave heights will be
rough to very rough Thursday through Saturday for the outer
waters.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 3 AM PDT
     Thursday for Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt
     Piedras Blancas 0-10 nm.

     Small Craft Advisory from 3 PM this afternoon to 3 PM PDT
     Thursday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt
     Reyes 10-60 NM.

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Murdock
MARINE...Murdock

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