Rip Current in California, January 5, 2019

Area Forecast Discussion
National Weather Service San Francisco Bay Area
353 PM PST Sat Jan 5 2019

.SYNOPSIS...Unsettled weather conditions will continue through the
remainder of the weekend with another round of widespread
rainfall and gusty winds forecast for Sunday. An active weather
pattern is likely to continue through next week with a storm
system set to impact the region Tuesday into Wednesday and another
late in the week.

&&

.DISCUSSION...as of 01:51 PM PST Saturday...The main cold front
has pushed through the region as of early this afternoon. As many
have noticed, the region has not received as much rainfall as
previously thought. It appears the front was more north to south
oriented as it moved inland over our region with a stronger narrow
cold-frontal band currently impacting southern California. With
this said, winds have ended up being the greatest impact with wind
gusts up to 70 mph in the highest peaks in the northern portion
of the region and 40 to 50 mph gusts even in the lower elevations
(52 mph gust reported at SFO around 12:25 PM PST). Wind speeds
have been moderate to locally gusty as well over the Central
Coast, yet not as strong as to areas in the San Francisco Bay
Area. Will keep the Wind Advisory in place through 4 PM PST as
winds are forecast to diminish region-wide as the surface low
pressure system pushes into northern California.

In wake of the frontal passage, showers have been on the increase
and are likely to continue through the afternoon as the atmosphere
becomes more unstable. While confidence is low, there continues to
be the potential for a few stronger storms to develop over the
region through the afternoon. Thus, cannot rule out strong gusty
winds mixing down with any thunderstorms that develop along with
small hail, brief heavy rainfall, and occasional lightning. Rain
showers will then tapper off through the evening and into early
Sunday morning. Snow levels remain on track to fall to around 4,000
tonight with the possibility of snow in the region's highest peaks,
especially in the Santa Lucia range.

While the region did not pick up much rainfall from this initial
cold front, the latest short-range models show another system
dropping southward along the back side of the mid/upper level trough
on Sunday. This should bring another chance of widespread rainfall
to the region with rain developing around or just after sunrise and
then spreading inland and to the south during the day. Look for the
North Bay and coastal ranges to pick up 1.00" to 2.00" (locally up
to 2.50" in the wetter spots). Most urban areas can expect around
0.33" (rain shadowed valleys) to 1.00" with locally higher amounts
possible within heavier showers that develop. It is worth noting
that the high resolution models do show amounts exceeding 3.00" in
the Santa Cruz Mountains and along the coastal ranges of the Big Sur
coast on Sunday. Overall, not expecting widespread flooding
concerns, especially given the lack of rainfall from today's system.

Winds will likely increase as well on Sunday as another surface low
approaches the coast. Thus, a Wind Advisory will likely be needed
for portions of the region on Sunday. Be sure to stay tuned for the
latest forecast information.

Long story short with respect to the remainder of the forecast
period, an active weather pattern is likely to continue into next
week. While a few showers may linger into Monday, it appears much of
the region will see a break in rainfall. Another cold front is then
projected to push inland Tuesday into Wednesday with another round
of wind and rain. The current forecast models show conditions drying
out Wednesday night into Thursday before another mid/upper level
system impacts the coast late in the week and into next weekend as
well.

&&

.AVIATION...As of 3:53 PM PST Saturday...for 00Z Sunday TAF
Package. Impactful morning and afternoon for all terminals with
strong southerly winds as well as MVFR ceilings (and even brief
IFR visibilities). Over the next several hours, winds at all
terminals should veer more southwesterly behind the frontal
passage. Winds will subside as the night progresses; however,
these lighter winds will be rather short-lived as winds will
become southeasterly again in advance of the next system that will
bring more strong winds, MVFR ceilings, and periods of rain.

Vicinity of KSFO...Conditions are forecast to gradually improve
over the next several hours as winds will acquire a bit more of a
westerly component as well as subside. Generally expect VFR
conditions to prevail with more SCT/BKN-type decks at or above
3,000 ft AGL, though, can't rule out brief periods of MVFR
conditions with a passing shower in this post-frontal environment.
The winds will continue to subside through the evening hours,
likely under 8 kts around midnight. By sunrise, though, winds will
become southeasterly again, as well as increase and become gusty
during the morning hours. Periods of rain will return by the
afternoon hours, as well as MVFR-level ceilings.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...MVFR/VFR conditions are anticipated over
the next several hours, with VFR conditions likely prevailing
later in the evening and overnight hours. Strong/gusty southerly
winds will become more southwesterly as the front passes through
MRY and SNS in the coming hours, then are expected to subside
through the evening. Winds will turn southeasterly again closer to
the morning hours ahead of the next approaching system that will
bring more strong winds, periods of rain, and lower ceilings.

&&

.MARINE...as of 03:33 PM PST Saturday...Coastal waters are
transitioning into the post frontal environment behind an
energetic cold front this afternoon. Widespread light to moderate
rain showers have developed in the wake of the front. Winds will
ease and shift towards the SW to W into the evening and overnight
but are expected to shift towards the S to SE ahead of the next
storm system arriving tomorrow. Another round of gusty possible
gale force winds are expected across the coastal waters  tomorrow.
Hazardous conditions for small craft vessels will exist  across
the coastal waters between these storm systems due to  squared
seas at 14-16 ft and seconds.

&&

.MTR WATCHES/WARNINGS/ADVISORIES..
     .Tngt...Wind Advisory...CAZ006-505>512-517-518-528>530
             SCA...Mry Bay
             SCA...Pt Arena to Pt Reyes 0-10 nm
             SCA...Pt Reyes to Pigeon Pt 0-10 nm
             SCA...Pigeon Pt to Pt Pinos 0-10 nm
             SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
             SCA...Pt Arena to Pigeon Pt 10-60 nm
             GLW...SF Bay until 9 PM

&&

PUBLIC FORECAST: RGass
AVIATION: Rowe
MARINE: DRP

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