Napa, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

803
FXUS66 KMTR 030207
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
707 PM PDT Wed Jul 2 2025

...New UPDATE, FIRE WEATHER...

.KEY MESSAGES...
Updated at 207 PM PDT Wed Jul 2 2025

 - Breezy northwest winds Thursday afternoon and evening.

 - Night and morning low clouds clearing to the coast each
   afternoon remains.

 - Near normal temperatures with a slightly below normal
   temperatures Thu & Fri.

&&

.UPDATE...
Issued at 649 PM PDT Wed Jul 2 2025

No changes needed to the forecast this evening as we turn our
attention to elevated fire weather conditions across higher
elevations in the East and South Bay tomorrow. A quick building
ridge will move through overnight before a deeper trough
approaches early Friday. This pattern change is already underway
as the 500 mb height has increased 30 m today (5820-5850). In
between the ridge and trough, strong upper level winds will mix
down to the higher elevations. While the temperatures drop a few
degrees, the air above the marine layer will dry out a bit. The
greatest impact will be from the strong winds, which will only
diminish marginally Friday. As a reminder, July 4th is by far the
day with the greatest wildfire starts across the country. Please
obey all firework restrictions to avoid a serious incident.

&&

.SHORT TERM...
Issued at 207 PM PDT Wed Jul 2 2025
(This evening through Thursday)

Water vapor satellite imagery shows the upper low tracking into
southern CA this afternoon. Behind it, weak upper level ridge has
taken it`s place. This will gradually be pushed to our east and
southeast by Thursday as the next upper level trough advances
towards the PacNW and northern CA. In addition to our routine
nighttime/morning clouds that clear to the coast each afternoon, we
will have slightly cooler high temperatures in the afternoon. We
will also be monitoring elevated to near critical fire weather
conditions for Diablo Range and Santa Cruz Mountains. Wind gusts
look to be around 25-40 mph higher terrain, and inland gaps/passes,
and for the aforementioned mountains RH values could fall to about
15-45% and recovering to 30-50% for the higher points of elevation.
The stronger wind gusts, of 25-40 mph, will also be observed over
the water and coastal areas.

&&

.LONG TERM...
Issued at 207 PM PDT Wed Jul 2 2025
(Thursday night through next Tuesday)

Upper level troughing looks to hold through the weekend, leading to
seasonably cool temperatures on the 4th. Expect the rinse and repeat
forecast in terms the stratus creeping in each night and then
receding to the coast each afternoon. Temperatures gradually become
seasonal over the weekend, putting us closer to the seasonal
averages.

A quick peak into next week shows we could see a pattern change
beginning around Wednesday. Cluster analysis shows high pressure
over the southwest building, which should kick off a warming
trend.

&&

.AVIATION...
(00Z TAFS)
Issued at 533 PM PDT Wed Jul 2 2025

IFR and MVFR CIGS are building along the coast along with mist and
drizzle and are affecting HAF as well as the Monterey Bay terminals.
Winds reduce across the region into the evening and CIGs look to
fall further into the night. Moments of low clouds also look to
affect OAK and the North Bay terminals later into Thursday morning.
Inland clearing begins in the mid morning with most TAF sites going
VFR before the midday. 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 Thursday afternoon, with gusty winds
expected around the SF Bay. Expect winds to reduce into Thursday
evening.

Vicinity of SFO...VFR through the TAF period. Breezy to gusty winds
reduce into early night, becoming moderate. Breezy west winds return
into the late morning on Thursday with stronger winds and around 31
kt gusts expected in the mid afternoon and through much of the
evening. These winds reduce in the late evening but look to stay
breezy through that night.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...MVFR CIGs fall to IFR levels into the night
as winds reduce. Winds become light overnight as LIFR CIGs form with
some pockets of mist and drizzle in the area. Winds become moderate
as again into mid to late Thursday morning CIGs erode over the
terminals, but expect cloud cover to linger over the Monterey Bay
itself.

&&

.MARINE...
(Tonight through next Tuesday)
Issued at 533 PM PDT Wed Jul 2 2025

A fresh to strong northwesterly breeze and rough seas will
continue through Thursday before diminishing slightly late week.
Gale force gusts will be likely across portions of the waters
tonight and again on Thursday. A low-amplitude long period
southerly swell will arrive Thursday and persist through Friday.

&&

.FIRE WEATHER...
Issued at 649 PM PDT Wed Jul 2 2025

Elevated fire weather conditions are expected Thursday afternoon
and evening in the East Bay Hills, Eastern Santa Clara Hills, and
Santa Cruz mountains driven by sustained winds as high as 30 mph.
A Red Flag Warning is not expected due to onshore winds and
moderate humidity. A cold front will move through Thursday, bringing
cooler temperatures and strong onshore wind. With lower
temperatures, the minimum RH will stay moderate with good
recovery overnight. Sustained winds will reach as high as 30 mph
in the higher elevations of the East and South Bay. While the wind
improves a bit, conditions remain elevated Friday (including
during peak firework time). Wind speeds will continue to decrease
through the weekend and into early next week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for SF Bay N of
     Bay Bridge.

     Small Craft Advisory from 3 PM to 9 PM PDT Thursday for Mry Bay-
     SF Bay N of Bay Bridge.

     Gale Warning until 9 PM PDT Thursday for Pt Arena to Pt Reyes 0-
     10 nm-Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory until 3 AM PDT Friday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory from 9 AM to 9 PM PDT Thursday for Pigeon
     Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory until 3 PM PDT Thursday for Pt Pinos to Pt
     Piedras Blancas 0-10 nm.

     Gale Warning from 3 PM Thursday to 3 AM PDT Friday for Pt Pinos
     to Pt Piedras Blancas 0-10 nm.

&&

$$

SHORT TERM...KR
LONG TERM....KR
AVIATION...Murdock
MARINE...RGass

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