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

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000
FXUS66 KMTR 250048
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
548 PM PDT TUE MAY 24 2016

.SYNOPSIS...Showers and potentially an isolated thunderstorm or
two will be possible over the inland hills/mountains through this
evening. Otherwise, temperatures will remain seasonably cool
through Wednesday with diminishing chances of showers. A gradual
warming and drying trend is then slated for the remainder of the
week and into the upcoming weekend.

&&

.DISCUSSION...as of 01:30 PM PDT Tuesday...Shower activity
showing up on KMUX Radar this afternoon, mainly over the higher
elevations of the Central Coast, far East Bay Hills/Mountains and
extreme northern portion of Napa County. Given the cool air mass
aloft, cannot rule out an isolated thunderstorm or two through the
early evening that may produce small hail. Area reporting gauges
do indicate brief moderate to locally heavy rainfall associated
with these showers. Otherwise, most of the major urban areas will
remain dry through the remainder of the day.

The broad mid/upper level trough and associated low pressure system
aloft will begin to slowly shift eastward, away from the region on
Wednesday. However, do expect low clouds to once again impact the
region overnight into Wednesday morning with the possibility of
patchy drizzle along the coast. Temperatures on Wednesday may warm
by a few degrees region-wide, yet will likely remain below seasonal
averages for one more day due to the proximate of the exiting
mid/upper level low. In addition, shower activity will be less
likely and more remote tomorrow afternoon, yet not completely out of
the question. For now, the best chance of any shower development on
Wednesday will be confined to the northeast portions of the North
Bay.

As the upper level trough ejects eastward into the Plains late in
the week, mid/upper level high pressure will build over the Eastern
Pacific. This will result in a gradual warming and drying trend
through the upcoming weekend. Daytime temperatures will likely
rebound back into the 70s to lower 80s inland while coastal
locations remain in the 60s to lower 70s. The warmer and drier
conditions will likely extended into early next week.

&&

.AVIATION...as of 5:48 PM PDT Tuesday...A closed upper level low
was centered 150 miles SW of the Monterey Peninsula this afternoon.
This low is forecast to move south tonight and be near Point Mugu
Wednesday morning.

Similar to yesterday there`s mostly convective clouds around the
area along with a mix of some ocean based strato-cu clouds (not
technically a marine layer due to a near abscence of low level
inversions per area profilers). The 00Z Oakland sounding showed a
very weak inversion at 900 mb however this temp profile`s colder
than current and typical sea temps.

00Z terminal forecasts follow persistence based on the slow moving
upper low and areas where up/down vertical motion are favored to
persist into this evening. 00Z Oak sounding indicates the amount
of water vapor throughout the column is similar to this morning
thus with onset of night-time cooling a trend toward increasing
low clouds is anticipated...in-line with recent model boundary
layer humidity forecasts. HRRR model forecasts inland convective
showers to end by 04z-05z this evening. Patchy drizzle or sprinkles
are a possibility Wednesday morning.

Vicinity of KSFO...As briefed by the dayshift and per most recent
vis imagery a continuous feed of low clouds persists from the CA
coastal waters. Tempo sct-bkn forecast this evening then prevailing
MVFR cig for the overnight. Westerly wind gusts to around 20 knots
til about 06z this evening. VFR forecast to return by late Wednesday
morning.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...Location of aformentioned low center is
resulting in cloud cover moving into the area from a general SE
direction. MVFR cigs forecast to develop 05z-06z timeframe. MVFR
cigs persist overnight with clearing by late Wednesday morning.

&&

.MARINE...as of 08:43 AM PDT Tuesday...Light to moderate winds and
small seas will persist today. Winds will increase tonight and
Wednesday as high pressure builds over the region. The winds will
be strongest north of Point Reyes.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tngt...SCA...Pt Arena to Pigeon Pt 10-60 nm from 3 AM
             SCA...SF Bay until 9 PM

&&

$$

PUBLIC FORECAST: RGass
AVIATION: Canepa
MARINE: MM


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