Small Craft Advisory 117, NWS San Francisco Bay Area, CA

Area Forecast Discussion
National Weather Service San Francisco Bay Area
217 PM PDT Wed Jun 14 2017

.SYNOPSIS...The region-wide warming trend is forecast to continue
today into Thursday as high pressure builds over the southwestern
portion of the country. By Friday and into the weekend, inland
temperatures will warm to as much as 20 degrees above seasonal
averages and begin to pose potential heat related illnesses. Dry
weather conditions and mostly clear/sunny skies will also prevail
through the forecast period.

&&

.DISCUSSION...as of 02:15 PM PDT Wednesday... Today marks the
return of above average temperatures and the mid point of a robust
warming/drying trend created as a result of a broad (but
relatively low amplitude) high pressure ridge. Temperatures are
generally running warmer across the board today as a result, with
the highest magnitude of warming (of 10+ degrees as of 1PM)
observed in the Santa Cruz mountains and the coastal North Bay
range near Guerneville, while 850MB temperatures increase by
around 4C over the last day. Warm air advection and subsidence
aloft will continue to contribute to a general warming and drying
trend through the remainder of this week and into this weekend.

For tomorrow, temperatures will warm by just a few degrees over
today, with a much larger increase in temperatures beginning on
Friday as 850MB temps rise to 20-22C. By this weekend, forecast
models show the broad ridge beginning to strengthen, especially
along the Pacific coastline. By Saturday, 850MB temperatures
rise further to 23-24C, bringing triple digit temperatures to the
surface and/or temperatures 20 degrees above normal. Overnight
lows through the next several days will generally run in the 50s
to low 60s for most valley communities, while lows in the 70s can
be expected for those living in the thermal belt at the top of the
nocturnal inversion in the hills/mountains.

The latest model runs indicate that Sunday will be just as warm,
if not warmer, than Saturday, which is a notable change compared
to previous forecast packages. This shift is occuring because the
four-corners ridge is strengthening and backbuilding into
California at a more intense rate that previously suggested.
Additionally, the four-corners high looks more likely to persist
over California into much of next week, continuing the trend of
above average temperatures for the area.

These hot temperatures come after an extended period of
unseasonably cool temperatures, so many individuals may have
trouble acclimating to the sudden heat. This may increase the risk
of heat related illnesses across the area. An excessive heat
watch has been issued for all non-coastal areas in our forecast
area for Friday through Sunday as a result. Please see the latest
NPWMTR for more information. And remember to look before you
lock-- dont leave pets or children in hot cars for any amount of
time.

While confidence is high that we will see these excessively warm
temperatures for our inland areas, the direction of the winds
will dictate how much of a warming/cooling effect near coast and
coastal regions the wind will provide. This is something that will
come play more for the late weekend/early next week and should
come into better focus as the short term models come into range.

Closer to the immediate coast, temperatures will be much more
seasonal as the marine influence moderates the weather there. For
those considering traveling to the coast to cool off this
weekend, please be advised that the ocean is very cold and can
quickly lead to hypothermia. In addition, rip currents can pull
beachgoers far out to sea. It is important to take a few minutes
to read about these hazardous and how to avoid them if you
infrequently visit the ocean.

&&

.AVIATION...As of 10:35 AM PDT Wednesday...For 18z TAFS. VFR
conditions currently at all terminals. VFR conditions expected to
prevail through the period with the exception of low cigs possible
tomorrow morning at KMRY and KSNS. Breezy onshore winds are
expected to develop by this afternoon with gusts up to 30 kt
possible at KSFO.

Vicinity of KSFO...VFR conditions expected with mostly clear
skies. Expect increasing W to NW winds this afternoon at 15 to 25
kt with gusts around 30 kt possible.

SFO Bridge Approach...Similar to KSFO but lighter winds.

Monterey Bay Terminals...Currently VFR. Morning low clouds have
cleared out. Expecting VFR conditions to prevail with increasing
westerly winds this afternoon. Return of MVFR/IFR cigs possible
tomorrow morning.

&&

.MARINE...as of 8:00 AM PDT Wednesday...Moderate northwesterly
winds will continue over the coastal waters through the remainder
of the week and through the weekend as high pressure remains over
the Eastern Pacific and a thermal trough develops over California.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tngt...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 Arena to Pigeon Pt 10-60 nm
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
             SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
             SCA...Mry Bay until 9 PM

&&

PUBLIC FORECAST: DRP
AVIATION: Anna
MARINE: Anna

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