Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

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FXUS66 KMTR 201130
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
430 AM PDT Mon May 20 2019

.SYNOPSIS...Dry weather conditions are expected through much of the
day ahead of another storm system set to arrive tonight. Look for
light rain to develop late this evening over the North Bay and then
across the remainder of the region overnight. Showers will linger
into Tuesday before the return of dry conditions Tuesday night into
Wednesday. Cool and unsettled conditions are likely through the
remainder of the week, yet widspread rainfall appears less likely.

&&

.DISCUSSION...as of 02:55 AM PDT Monday...Isolated showers linger
off of the Central Coast early this morning as the core of a cold
mid/upper level low shifts eastward away from the region.
Expecting a drying trend to continue region-wide through much of
the day with temperatures warming only into the 60s for most
locations this afternoon. A mix of sun and clouds can also be
expected through the afternoon ahead of the next approaching
weather system.

Another mid/upper level storm system is forecast to push inland over
the Pacific Northwest today with the tail end of a frontal boundary
dropping across the San Francisco Bay Area late this evening and
through the Central Coast tonight. Light rain will first develop
over the North Bay this evening before spreading southward/inland
during the overnight hours. Rainfall will generally range from a few
hundredths of an inch to around one-quarter inch through the night.
In wake of the frontal passage, lingering showers will persist into
Tuesday as the core of the mid/upper level trough drops southward
over the West Coast. The post frontal showers will be mostly
isolated to scattered in nature with the potential for brief
moderate to locally heavy rainfall. Overall, this system will be
weaker and produce less rainfall than the system that moved across
the region this past weekend.

Drier weather is forecast to develop Wednesday and likely to persist
into late week. However, a broad upper trough remains over the
western portion of the country keeping temperatures below seasonal
averages. The best chance for precipitation looks to stay over the
interior portion of the state. Chances for precipitation may return
late in the week and into the upcoming weekend as weak disturbances
round the base of the retrograding trough. Thus, look for cool and
unsettled conditions to persist through the end of the month.

&&

.AVIATION...as of 04:30 AM PDT Monday...For 12z tafs. Showers have
mainly ended across the region. Ample low level moisture remains
in place leaving patchy MVFR cigs and fog in the North Bay. Cigs
should become more widely scattered by late this morning. An
upper low will bring increasing clouds and westerly winds to the
area tonight along with some scattered showers. Winds may be gusty
tomorrow morning.

Vicinity of KSFO...Patchy cigs around the Bay Area between
2000-4000 ft AGL. Cigs may occasionally become BKN this morning
before scattering out by the afternoon. West to southwest winds
through the period becoming gusty tomorrow morning. Cigs will
lower as showers approach this evening.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...Showers have mainly ended with patchy
VFR/MVFR cigs 2500-5000 ft through mid morning. Cigs will
redevelop early this evening as showers approach.

&&

.MARINE...as of 02:55 AM PDT Monday...Generally light west to
northwest winds will persist over the coastal waters through
tonight before increasing on Tuesday. Winds will then remain
elevated through late this week. Large swells generated by the
last storm system will continue to create hazardous conditions,
particularly for smaller vessels. West to northwest swell will
briefly decrease later today and tonight before building again
Tuesday and Wednesday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tday...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...Pt Arena to Pigeon Pt 10-60 nm
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
             SCA...Rough Bar Advisory for SF Bar until 4 PM
             SCA...Mry Bay from 1 PM

&&

$$

PUBLIC FORECAST: RGass
AVIATION: AS
MARINE: AS

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