Saranap, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

385
FXUS66 KMTR 222119
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
219 PM PDT Tue Apr 22 2025

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

.SYNOPSIS...
Issued at 218 PM PDT Tue Apr 22 2025

A pattern change happens tomorrow, which will kick off a cooling
trend through the weekend. Patchy drizzle and fog will be possible
if the marine layer Wed and Thu morning. Light rain and/or drizzle
is possible Fri into Saturday, with the best chances appearing to
be over the North Bay.

&&

.SHORT TERM...
(This evening through Wednesday)
Issued at 218 PM PDT Tue Apr 22 2025

Short Term Key Messages
*Slight chance for drizzle and patchy dense fog
*Cooling trend begins

A shortwave trough passes over the PacNW Wed into Thu, placing weak
troughing over us. This will increase onshore flow during this
period, which should allow the marine layer to deepen and penetrate
farther inland. Modest moisture looks to come with the onshore flow
and that should lead to pockets of drizzle late tonight and into Wed
morning. The most favorable areas look to be on along the coast, the
Monterey Bay area, and perhaps around San Francisco Bay, in addition
to areas with orographic lift. Currently have the drizzle/fog
potential ending around 11AM, with stratus clearing for the North,
East, and South Bay interior valleys. Coastal communities may
struggle a bit longer and could potentially see stratus and drizzle
linger to lunch time. High temperatures will range from near normal
to about 10 degrees below their normal for this time of year.
Ridges, gaps, and perhaps even some associated channels/valleys may
see gusts up to 20-35 mph Wed afternoon and evening.

&&

.LONG TERM...
(Wednesday night through next Monday)
Issued at 218 PM PDT Tue Apr 22 2025


Long Term Key Messages
*Increased onshore flow and a cooling trend through Saturday
*15-45% chance for drizzle/light rain Friday/Saturday

Onshore flow continues into Thu, pushing more moisture into the
region. This should lead to another cloudy night with pockets of
drizzle, similar to Tue night into Wed morning. Skies look to be
mostly cloudy during this time frame with more a brief period of
zonal flow setting up. Another cool day will be on tap with high
temperatures around 5 to 15 degrees below their normal. The signal
for gusty ridge, gap, and associated valley/channels shows up again
where they peak around 20-35 mph Thu afternoon and evening.

By Friday, models and cluster analysis agree that an upper level
troughing deepens. There is still some uncertainty as to how strong
or how far south this system goes and if it closes off. There is
some agreement that it has shifted a bit more south, which has
increased the PoP forecast across the region with the highest
amounts being in the North Bay and for higher elevation terrain.
Confidence still remains a bit on the lower side for rainfall
accumulation as we`re still only expecting light rain or drizzle.
The latest forecast gives a smattering of a 0.01-0.10" for those in
the North Bay mountains, along the Bay Area coast, and into the
Central Valley mountains. This will likely change over the next few
days as we get closer to the event.

As we head into early next week, clusters show upper level troughing
moving east with upper level ridging returning. This should put
temperatures closer to their seasonal normals.

&&

.AVIATION...
(18Z TAFS)
Issued at 1017 AM PDT Tue Apr 22 2025

Currently a mixed bag of IFR-VFR across the board with brief
widespread VFR expected this afternoon. High confidence in all
terminals experiencing a reduction to at least MVFR overnight as
an upper-level trough deepens the marine layer, allowing it to
penetrate further inland. Onshore flow will prevail through the
TAF period.

Vicinity of SFO...Currently VFR with offshore flow. High
confidence in MVFR conditions returning to the terminal overnight.
Winds will prevail out of the west once the sea breeze kicks in
this afternoon.

SFO Bridge Approach...San Mateo Bridge Approach continues to
clear with the low clouds remaining within the San Francisco Bay
expected to clear by the top of the hour.

Monterey Bay Terminals...Currently IFR with westerly flow at MRY
and MVFR with northerly flow at SNS. Stratus is expected to
continue retreating back toward the coast with VFR expected at
both terminals by this afternoon. Both terminals have an 80%
chance of IFR conditions returning this evening. Westerly winds
will prevail through the TAF period.

&&

.MARINE...
(Today through Sunday)
Issued at 913 AM PDT Tue Apr 22 2025

Strong northwesterly winds over the outer waters will continue
through Wednesday with gale force gusts expected over the
northern outer waters. Rough seas will be expected in the outer
waters through Wednesday. Moderate northwesterly winds and
moderate seas will prevail Thursday through Saturday with a chance
for light rain or drizzle Friday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Thursday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory until 9 AM PDT Wednesday for Pt Reyes to
     Pigeon Pt 0-10 nm.

     Small Craft Advisory from 9 AM Wednesday to 3 AM PDT Thursday
     for Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 3 PM PDT this afternoon for Pt Arena
     to Pt Reyes 10-60 NM.

     Gale Warning until 9 AM PDT Wednesday for Pt Arena to Pt Reyes
     10-60 NM.

&&

$$

SHORT TERM...KR
LONG TERM....KR
AVIATION...Sarment
MARINE...Sarment

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