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

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FXUS66 KMTR 282102

Area Forecast Discussion
National Weather Service San Francisco Bay Area
202 PM PDT Wed Jun 28 2017

.SYNOPSIS...Seasonable summer pattern in place with a marine layer
along the coast leading to areas of night and morning low clouds
followed by sunny afternoons away from the coast right through the
4th of July Holiday.

&& of 2:02 PM PDT Wednesday...Marine layer has
compressed slightly to just under 2000 feet along the coast.
Marine clouds have been stubborn to clear from Pt Reyes to San
Mateo as well as around the south end of Monterey Bay with
persistent northwest winds. Current temperatures are running
seasonably cool with only mid 70s for the inland valleys.

In general high pressure will strengthen slightly tonight into
Thursday which should compress the marine layer and weaken onshore
flow. So if anything the inland valleys should notice a slight
warming trend through the end of the work week. As the marine
layer compresses nighttime fog may be dense at times near the
coast and coastal hills with early morning drizzle associated with
the night time marine intrusions.

The next upper trough arrives around 00z Saturday, which will
likely lead to a stronger seabreeze Friday evening with a
deepening of the marine layer. Latest 18z nam actually spits out a
few hundredths of precip by 12z Saturday morning as a result of
local drizzle associated with a deep marine layer.

850 mb temps look to stay in the 21-24 celsius range though the
weekend and into early next week. So in what will likely be a long
holiday weekend for many people it looks like dry and seasonable
pattern with perhaps slight cooling trend towards July 4th. Quiet
summer pattern overall.


.AVIATION...As of 10:47 AM PDT Wednesday...For 18z TAFs. 2000 ft
marine layer is holding strong this morning across much of the
immediate coastline along Central California. SFO and OAK barely
scattered out yesterday, due to local effects of the marine layer,
before stratus built back in early yesterday evening. Today has
the potential to be similar. However, tafs do reflect clearing
(VFR) by 1830-19z at all terminals. Will monitor accordingly.
Breezy onshore winds again this afternoon, ranging from 10 to 20
kt, with occasional gusts over 20 kt at SFO. Cigs return early
again tonight.

Moderate confidence.

Vicinity of KSFO...Borderline IFR/MVFR cigs through 18-19z, but
could potentially be later. VFR anticipated by early afternoon.
Winds 15-20 kt, with gusts around 25 kt through early evening.
MVFR to IFR cigs set to return around 04-05z, but will ultimately
depend on when/if clearing occurs this afternoon.

SFO Bridge Approach...Approach will clear before terminal,
sometime around 18-1830z.

Monterey Bay Terminals...Satellite shows nice clearing through the
Salinas Valley. SNS should be clear by 18z, followed by MRY by
1830-19z. Moderate and occasionally gusty westerly winds this
afternoon, 10-15 kt on average. Cigs return by early evening or
late afternoon.

&& of 01:42 PM PDT Wednesday...Northerly winds will
continue to increase along the Central Coast as high pressure
builds off the coast. Gusty winds will result in hazardous sea
conditions with steep wind waves and fresh swell.


     .Tngt...SCA...Pigeon Pt to Pt Pinos 0-10 nm
             SCA...Pt Arena to Pt Reyes 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...Pt Reyes to Pigeon Pt 0-10 nm until 3 AM
             SCA...Mry Bay until 9 PM
             SCA...SF Bay until 9 PM




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