Rip Current in California, May 4, 2019

Area Forecast Discussion
National Weather Service San Francisco Bay Area
1033 AM PDT Sat May 4 2019

.SYNOPSIS...A cooling trend is forecast over the weekend as an
upper level low approaches the central California coast from the
west, deepening the marine layer. This system will also bring an
increase in cloud cover and shower chances from Sunday through
Monday morning, primarily for areas south of the SF Bay Area. Dry
conditions districtwide are expected Monday afternoon through
through at least midweek.

&&

.DISCUSSION...As of 9:05 AM PDT Saturday...The marine layer
deepened overnight and is now about 1800 feet per the Fort Ord
profiler. Visible satellite imagery shows that low clouds are
still filling all inland valleys, thus clearing will occur late
near the coast. Temperatures are running cooler than yesterday at
this time at most locations, and surface pressure gradients are
pretty flat with only 1.4 mb from SFO to SAC, and 0.1 mb from SFO
to ACV. May have to lower some of today's max temps - doubtful if
some near-coastal areas will reach very far into the 60s.

Meanwhile, the upper low, currently located about 680 miles west
of Point Conception, continues to approach the central coast.
Latest models all have this low center reaching the Big Sur coast
by midday Sunday, and there is a consensus now concerning the
possibility for scattered showers, starting in for Monterey
county Sunday afternoon, and then into the Bay Area Sunday night
into Monday. Widespread rain is not expected, rather, hit and miss
showers will be the more likely scenario. After moving inland the
upper low is then forecast to move southeast and exit the state
Tuesday.

Continued cool temperatures are expected through Tuesday with
gradual warming into midweek. After midweek, there are still
questions surrounding a retrograding trough and whether or not it
will move far enough west to bring rain to the district late in
the week. The forecast is dry for now, but something to watch
over the next few days.

&&

.AVIATION...as of 10:33 AM PDT Saturday...For 18z tafs. Satellite
imagery showing stratus dissipating inland with low clouds
lingering along the coast. The marine layer has deepened to around
2,000 ft AGL per the Fort Ord profiler. VFR conditions to prevail
into this evening before stratus is forecast to return. MVFR to
IFR conditions expected tonight through tomorrow morning. Light
winds this morning to become onshore this afternoon 10-15 kt.

Vicinity of KSFO...VFR conditions through this evening before
stratus returns. Timing on the return of stratus this evening is
uncertain. Latest run of the local WRF model shows low clouds
moving into the area as early as 04z with other model guidance
holding off until 06z/07z. Regardless, expect MVFR conditions
overnight and through tomorrow morning. Onshore winds through the
period increasing this afternoon to around 15 kt.

SFO Bridge Approach...similar to KSFO

Monterey Bay Terminals...Satellite imagery shows low clouds have
dissipated this morning leaving VFR conditions. Expect VFR to
prevail into the late afternoon/early evening before marine
stratus returns. Low clouds could move into KMRY as early as 00z.
Cigs to lower to IFR overnight and persist into tomorrow morning.
Generally light winds through the period 10 kt or less.

&&

.MARINE...as of 8:04 AM PDT Saturday...Generally light northwest
winds will continue over the coastal waters this weekend as high
pressure remains off the coast of the Pacific Northwest. Locally
breezy conditions possible this afternoon and evening in the
northern San Francisco Bay near the Golden Gate and around Angel
Island. Winds will turn west to southwest tonight as an upper low
approaches the California coast. A mixed light northwest swell and
long period southerly swell will continue into next week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tday...SCA...SF Bay from 3 PM

&&

PUBLIC FORECAST: Sims
AVIATION: AS
MARINE: AS

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