Day Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

307
FXUS66 KMTR 112303
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
303 PM PST Wed Dec 11 2024

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

.SYNOPSIS...
Issued at 300 PM PST Wed Dec 11 2024

Key Messages:
- Multiple rounds of rainfall tonight through the weekend
- Light rain may start as soon as 7-8pm tonight across the North Bay
- Periods of moderate rain after midnight through sunrise tomorrow
over the North Bay
- Rainfall shifts south and east across the Bay Area, East Bay and
rest of the Central Coast through the remainder of tomorrow morning
- First wave of rainfall exits east by early Thursday afternoon
- More impactful, longer duration rainfall expected Friday evening
through Saturday with gusty south winds during that time as well
- Another round of primarily light rain arrives late Sunday into
Monday with minor impacts expected
- Coastal flooding impacts will be further enhanced by the timing of
a King Tide tomorrow through the weekend, which will also result in
beach hazard concerns

&&

.SHORT TERM...
(This evening through Thursday)
Issued at 300 PM PST Wed Dec 11 2024

Not much change in thinking wrt rainfall set to arrive across the
North Bay later this evening. The North Bay coastal ranges will
begin to see pre-frontal rain develop as early as 7-8pm tonight as a
strengthening closed low approaches NorCal later during the
overnight. Steadier, light to moderate rainfall will gradually
expand in coverage after midnight from the North Bay south and east
across the Bay Area and the remainder of the Central Coast,
eventually shifting east of our area by early tomorrow afternoon.

Overall, portions of the North Bay, especially the coastal ranges
can expect 1.5 to 2.5" of rainfall by late tomorrow morning. The
highest rainfall rates should peak at around 0.5"/hr in the 1am-4am
time frame along the coastal ranges, and otherwise hover around
0.25"/hr as the system moves inland Thursday morning.

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 300 PM PST Wed Dec 11 2024

Light rain will linger Thursday afternoon through early Friday as
weak mid-level shortwaves transect our area out ahead of the next
system as it strengths over open water. The leading edge of more
intense rainfall rates arrive along the coastal ranges of the North
Bay by Friday evening. A +100kt H30 SSW-NNE oriented jet develops
over our area Friday night with more widespread moderate rainfall
expected during the overnight Friday, beginning over the North
Bay once again, gradually spreading south and east through the
remainder of the day Saturday across the rest of our area. Coastal
ranges farther south from the Bay Area to the Santa Lucias may
see 1-2" Friday night through early Sunday with the remainder of
our interior locations looking at wetting rains between 0.25" to
0.75". Sunday is mostly dry before another disturbance arrives for
the beginning of next week. Attm, it appears to be a fairly
progressive trough, with 0.5" to 1.0" possible from the Bay Area
north, with lesser amounts across the East Bay and the remainder
of the Central Coast.

&&

.AVIATION...
(18Z TAFS)
Issued at 1007 AM PST Wed Dec 11 2024

A cold front will bring strong winds and widespread rain to the
region. Winds will initially be out of the south, strengthening as
the cold front approaches, transitioning to become northwesterly in
its wake. Ceilings will lower into the evening with rain set to
begin late tonight. Steady rain overnight will be followed by
post-frontal rain showers tomorrow morning.

Vicinity of SFO...Currently VFR with easterly flow. Winds will
slowly start to back, strengthening and becoming southerly ahead of
the cold front. Steady rain is expected 07Z-13Z with post-frontal
rain showers expected through the afternoon.

SFO Bridge Approach...Slant range visibilities will likely be
reduced due to haze.

Monterey Bay Terminals...Currently VFR and calm at MRY and VFR with
drainage flow at SNS. Steady rain is expected 10Z-16Z with post-
frontal rain showers continuing through the morning.

&&

.MARINE...
(Tonight through next Monday)
Issued at 201 PM PST Wed Dec 11 2024

Unsettled weather returns today with a parade of storms set to
impact the West Coast over the next week. Waveheights will remain
rough to very rough during this time. Winds will be strong out of
the south with gale-force gusts likely. Widespread rainfall is
expected each day except Sunday where some rain showers may
linger. Slight thunderstorm chances also exist over the weekend.

&&

.BEACHES...
Issued at 201 PM PST Wed Dec 11 2024

There will be multiple hazards across the Bays, Pacific Ocean, and
their associated beaches as three storm systems take aim at the West
Coast and King Tides return. A Coastal Flood Advisory has been
issued from 6 AM Thursday through 1 PM Monday along the bayshore of
the San Francisco Bay and San Pablo Bay with the highest tides: 6.74
ft at 8:12 am Thursday, 6.98 ft at 8:54 am Friday, 7.07 ft at 9:37
am Saturday, 7.02 ft at 10:22 am Sunday, and 6.82 ft at 11:08 am
Monday. These very high tides in tandem with long period
northwesterly swell will allow for large sets of waves to run a lot
farther up the beaches. A High Surf Advisory has been issued for 1
PM Thursday through 4 AM Friday for all west and northwest facing
beaches for breaking waves of 18-22 feet. Other impacts will be rip
current risk, longshore current risk, gale-force gusts, slight
thunderstorm chances, and widespread rainfall. There are going to be
poor conditions everywhere, especially on the water or at the
beach.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory from 6 AM Thursday to 1 PM PST Monday for
     CAZ006-506-508.

     High Surf Advisory from 1 PM Thursday to 4 AM PST Friday for
     CAZ006-505-509-530.

PZ...Small Craft Advisory from 9 PM this evening to 3 PM PST Thursday
     for SF Bay N of Bay Bridge.

     Small Craft Advisory from 3 AM Thursday to 3 AM PST Friday for
     Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos
     10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory from 9 PM this evening to 3 AM PST Friday
     for Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10
     nm.

     Small Craft Advisory until 3 AM PST Friday for Pt Arena to Pt
     Reyes 10-60 NM.

&&

$$

SHORT TERM...JM
LONG TERM....JM
AVIATION...Sarment
MARINE...Sarment

Visit us at www.weather.gov/sanfrancisco

Follow us on Facebook, Twitter, and YouTube at:
www.facebook.com/nwsbayarea
www.twitter.com/nwsbayarea
www.youtube.com/nwsbayarea