241
FXUS66 KMTR 312131
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
231 PM PDT Mon Mar 31 2025

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

.SYNOPSIS...
Issued at 201 AM PDT Mon Mar 31 2025

Rain, wind, and a slight chance for thunderstorms through
tomorrow. Warming and drying trend kicks off Wednesday.

&&

.SHORT TERM...
(This evening through Tuesday)
Issued at 230 PM PDT Mon Mar 31 2025

An upper level low off the Pacific Northwest coast will continue to
gradually move inland tonight into tomorrow through southwest Oregon
into NoCal. Out ahead of the main portion of the system today, a
relatively weak cold front is just now moving into the North Bay
early this afternoon and will continue south and east through the
remainder of today and this evening. Impressive H30 wind speeds
around 130kts will continue to stream across our region tonight into
early Tuesday morning, and then begin to ease on the backside of the
system as the center moves farther inland. However, the trough will
broaden over our area as the primary system shifts east keeping
cooler air aloft in place over the west through the middle of the
week. Slight chances for isolated thunderstorms this afternoon and
evening are associated with the surface front moving through our
area. Thunderstorm chances in the post-frontal environment Tuesday
will be driven by cold temperatures aloft enhancing low level
lapse rates. Convective chances in the morning across the North
Bay and Bay Area will shift south through the afternoon into the
Central Coast, waning by sunset. The coastal ranges and inland
valley upslope flow will provide enough lift for up to one inch of
rain by Tuesday evening. Most locations will see trace amounts up
to one tenth of an inch of rain. Farther south, the highest spots
in the Big Sur and Santa Lucias may see an inch or two of snow.

&&

.LONG TERM...
(Tuesday night through next Sunday)
Issued at 230 PM PDT Mon Mar 31 2025

A large amplitude ridge of high pressure begins to build in on the
backside of the upper low on Wednesday. Cooler temperatures will
linger Wednesday and Thursday (along the coast) before a very
pleasant warmup on Friday into the weekend for the whole region.
Extended guidance hints at the potential for another upper level
system to bring light rain chances as soon as Sunday evening to the
North Bay, with little to no impacts expected attm.

&&

.AVIATION...
(18Z TAFS)
Issued at 1127 AM PDT Mon Mar 31 2025

Scattered showers will continue across the region leaving us with
MVFR conditions at times as they move through. Otherwise, VFR
conditions will prevail with gusty westerly winds occuring. Gusts to
20-25 kt, isolated 30kt at times, will be possible through the
afternoon before decreasing later on in the period. There may be a
lull in the rain this evening, with showers returning late tonight
and into tomorrow morning. Thunder should be minimal this afternoon
across the majority of the region , with perhaps a few couple
rumbles of thunder possible in Sonoma County.

Vicinity of SFO...VFR conditions should prevail through the
afternoon and evening, though vicinity showers may mover through
which could bring MVFR cig and vis at times. Outside of that, gusty
westerly winds are forecast through the afternoon and early evening
where gusts to 20-25kt are possible. A period of dry weather is
expected through the early overnight hours, before showers return
early tomorrow morning.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...A mix of sun and clouds are being observed
around the Monterey Bay terminals this morning, with showers
currently to the north of the region. We may see a few showers
straggle south this afternoon with the better chance for rain being
tomorrow morning. Outside of that, gusty westerly winds up to 20-
25kt will be possible this afternoon. Should a shower pass over MVFR
cig and vis will be possible. Otherwise VFR conditions prevail for
much of the period.

&&

.MARINE...
(Today through Saturday)
Issued at 955 AM PDT Mon Mar 31 2025

A cold front is moving through the coastal zones bringing
scattered showers, strong westerly wind, and a slight chance for
thunderstorms through the day. By Tuesday, a large W-NW swell
will build as the strong breeze shifts from W to NW. Significant
wave heights will peak at around 15 feet Tuesday before subsiding
Wednesday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 AM to 9 PM PDT Tuesday for Mry Bay-
     Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras
     Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm-SF Bay N of
     Bay Bridge.

     Small Craft Advisory until 9 PM PDT Tuesday for Pt Arena to Pt
     Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory from 9 PM this evening to 9 PM PDT Tuesday
     for Pigeon Pt to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...JM
LONG TERM....JM
AVIATION...KR
MARINE...KR

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