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

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FXUS66 KMTR 260540

Area Forecast Discussion
National Weather Service San Francisco Bay Area
1040 PM PDT Thu May 25 2017

.SYNOPSIS...Seasonably cool temperatures will continue into
Friday with a deep marine layer near the coast. Seasonable
temperatures on Saturday should trend warmer inland by Sunday and
Memorial Day Monday. Aside from the isolated coastal drizzle, dry
weather forecast through the next 7 to 10 days.


.DISCUSSION...As of 9:00 PM PDT Thursday...Cool temperatures were
observed across the region today with most locations topping out
in the mid 50s to mid 60s. Warmest inland locations reached into
the low 70s. It was a mixed bag of trends with some locations
warming a few degrees with others cooling as much as 22 degrees
over yesterdays temperatures. The deep marine layer allowed for
significant inland intrusion of the cool marine air and cloudy
conditions limited the amount of, if any, sunlight to reach the
ground. Low pressure over the region will maintain the deep and
undefined marine layer across the region through Friday and hence
similar temperatures to those that were seen today. Coastal
drizzle will once again be possible Friday morning.

The upper level trough that currently dominates the western United
States is forecast to begin moving eastward on Friday. This will
allow a shortwave ridge to build over California beginning
Saturday, and result in a modest warming trend for inland areas
over the Memorial Day Weekend. However, coastal areas are not
expected to warm much over the weekend since onshore flow will
continue, along with a persistent marine layer.

Longer range models indicate the arrival of a trough along the
West Coast around the middle of next week which should result in
at least slight cooling for inland areas during the second half of
the week.


.AVIATION...As of 10:40 PM PDT Thursday...A deep marine layer and
southerly low level onshore flow will maintain widespread MVFR
ceilings across the region overnight and into Friday morning.
Low clouds are expected to scatter out in most areas by late
Friday morning or early Friday afternoon. Winds will generally be
light from the south and southwest.

Vicinity of KSFO...MVFR ceilings expected to develop by 07Z and
continue until about 17-18Z Friday. However, southerly flow over
the Santa Cruz Mountains may result in sufficient downslope
warming and drying to delay development of low clouds and lead to
earlier clearing on Friday. Light southwest winds overnight and
into Friday morning, increasing in the afternoon.

SFO Bridge Approach...Similar to KSFO except likely earlier
development of ceilings this evening.

Monterey Bay Terminals...MVFR ceilings expected overnight and
through Friday morning with likely VFR conditions during Friday
afternoon, followed by early return of low clouds Friday evening.
Light south to southwest winds.

&& of 07:48 PM PDT Thursday...Gusty south to southwest
winds along the coast and over the bays will diminish through the
late evening. generally light winds are then expected overnight
and into friday. high pressure will  redevelop over the eastern
pacific late week and into the  memorial day weekend bringing a
return to more typical afternoon  and evening onshore winds to the
coastal waters and bays.




MARINE: Dykema

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