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

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FXUS66 KMTR 261155

Area Forecast Discussion
National Weather Service San Francisco Bay Area
455 AM PDT Fri May 26 2017

.SYNOPSIS...Deep marine layer with nearly all areas starting the
day cloudy which will keep temperatures on the cool side of normal
today. Saturday will trend back towards seasonable temperatures as
high pressure begins to build. Dry and warmer Sunday and Monday.
Another trough begins to approach by Tuesday and Wednesday with a
modest cooling trend and continued coastal clouds.

&& of 2:46 AM PDT Friday...Profiler data shows the
marine layer is very deep, around 4000 feet with fairly cool
temperatures aloft. This has allowed higher based marine clouds to
spread over nearly all locations in the district. The sfo to sac
gradient is weaker this morning at 1.2 mb onshore with lighter
winds most locations. Nonetheless the widespread clouds and upper
trough just to our east will once again keep temperatures on the
cool side of normal today, especially inland.

The trough axis nudges inland over the Great Basin while high
pressure begins to build Saturday. This will allow inland
temperatures to trend back closer to normal with more readings
into the 70s vs the cool 60s forecast for today.

High pressure continues to build Sunday with inland areas warming
back into the 70s and lower 80s. So pleasant weather for the
upcoming holiday weekend with no real hot weather to contend with
but still warm enough to use the pool. Beaches will remain cool
with onshore flow in place. SST have trended a few degrees warmer
the last few days as stronger nw winds have eased allowing SST to
warm back into mid 50s and in turn keep overnight lows a little
more mild near the coast and coastal valleys.

It`ll stay seasonably warm inland for Memorial Day with inland
highs from the mid 70s to mid 80s. The beaches will stay in the
upper 50s and 60s as another trough will approach by Monday
afternoon with increasing onshore winds. The models almost want to
generate some qpf around the middle of next week with the next
trough but that seems dubious at this time so will keep the
forecast dry. Trend should be for cooling back to seasonable norms
Tuesday and Weds with longer range ecmwf wanting to build a warm ridge
the second half of next week.


.AVIATION...As of 4:55 AM PDT Friday...A deep marine intrusion
bringing mostly MVFR to VFR cigs across the region this morning.
Ceilings of 2500-3500 ft AGL around the Bay Area, but may descend
down to 2000 ft into sunrise. The deep marine layer will mix out
between 17-19Z, depending on location. Light to breezy south to
southwest winds today.

Vicinity of KSFO...Borderline MVFR to VFR cigs this morning. Light
S-SW winds, increasing to become breezy in the afternoon. Stratus
returns tonight.

SFO Bridge Approach...Similar to terminal.

Monterey Bay Terminals...Primarily MVFR as stratus deck lingers
around the coast. A few pockets of IFR. Light S-SW winds,
increasing in the afternoon to become breezy.

&& of 02:24 AM PDT Friday...Light onshore flow and
moderate seas expected through tonight into Friday. Winds will
increasing over the Memorial day weekend as high pressure
redevelop over the eastern Pacific.






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