Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area Forecast Discussion
National Weather Service San Francisco Bay Area
232 PM PDT MON JUL 25 2016

.SYNOPSIS...An inland warming trend will get underway on Tuesday
and persist through late week as high pressure aloft builds in
from the Desert Southwest. However, as onshore flow persists,
cooler conditions along with some overnight/morning clouds will be
likely near the coast. Region-wide cooling is then forecast for
the upcoming weekend as the high pressure weakens and an upper
level trough develops off of the Pacific Northwest Coast.

&& of 02:19 PM PDT Monday...While most inland cloud
cover has retreated to the coast, a deeper marine influence has
resulted in a general cool down compared to yesterday afternoon
over much of the region. This trend will be short lived as
mid/upper level high pressure builds westward from the Desert
Southwest through the remainder of the week. As a result, the
marine layer is forecast to become more compressed overnight with
less inland penetration of stratus tonight into Tuesday morning. 

Also expecting smoke and haze to impact the region through at
least Tuesday, especially the Monterey Bay Region as the Sobranes
Fire continues down the Big Sur Coast. Please see the Fire Weather
section below for additional details.

Temperatures region-wide, especially inland, will rebound back to
above seasonal averages tomorrow afternoon. Expecting widespread 90s
in the inland valleys and hills/mountains while upper 70s to 80s will
be common near the bays. Many of the warmest inland spots will
likely reach into the 100-105 degree range. Along the immediate coast
and across San Francisco, daytime temperatures will remain cooler,
generally in the 60s as onshore flow persists. These warmer
conditions will persist through at least Thursday as the ridge aloft
remains the dominate weather driver across the region. Do expect
some minor day to day fluctuations in the depth of the marine layer
and associated overnight/morning low clouds and cooler coastal

It is also worth noting that both the NAM and GFS do show an
increase in mid-level moisture advection into the region from late
Wednesday into Thursday from our southeast. At this time, any
potential for high based/elevated convection appears to remain over
the interior portion of the state, well east of our region. However,
will continue to monitor the forecast models in the coming days for
any potential for convection. Again, the forecast remains dry
through the forecast period at this time given the strong high
pressure ridge aloft. 

By the weekend, the models generally agree in a slight cooling
trend back to near seasonal averages as the high pressure weakens
and another mid/upper level trough develops off of the Pacific
Northwest Coast.

&& of 11:15 AM PDT Monday...Widespread stratus
coverage continues along the coast but has now cleared from around
San Francisco Bay, and should retreat to near the shores of
Monterey Bay within the next hour or so. Otherwise skies are
mostly clear, but with areas of smoke and haze from the wildfire
in Big Sur in the southern half of the district. Latest profiler
reports show the marine layer depth sloping upwards from about
1200 ft at Bodega Bay to near 1600 ft at Ft Ord/Monterey Bay. Low
cloudiness is expected to extend back inland this evening and
overnight, but less extensively than last night and with earlier
clearing on Tuesday as an upper level ridge builds in from the

Vicinity of KSFO...VFR conds continuing this afternoon and evening
with stratus return not expected until late overnight.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...Ceilings expected to clear by early
afternoon but then return this evening. Areas of smoke and haze
from the Big Sur wildfire will continue at times.

&& of 09:31 AM PDT Monday...Moderate to gusty northerly
winds will prevail over the coastal waters as high pressure
remains off the West Coast. The stronger winds will be mainly
over the outer waters north of Pigeon Point. Winds will gradually
decrease Tuesday, but remain gusty north of Point Reyes.


.FIRE of 02:19 PM PDT Monday...Smoke from the
Sobranes Fire is impacting heavier populated areas today across
the Monterey Bay Region and points to the north and northeast.
This is a result of winds aloft becoming more southerly, compared
to previous days when the smoke was being blown southward out over
the Pacific. Meanwhile, surface winds remain light and variable
and more terrain driven over the fire. Expecting a warming and
drying trend over the region the next few days as the
aforementioned high pressure builds in from the Desert Southwest.
This will also compress the marine layer down to around (or below)
1000 feet and make for more challenging fire weather conditions in
the coming days. However, strong surface winds are not expected
through at least midweek.


     .Tngt...SCA...Pt Arena to Pigeon Pt 10-60 nm
             SCA...Pt Arena to Pt Reyes 0-10 nm until 11 PM
             SCA...SF Bay until 9 PM




Visit us at

Follow us on Facebook and twitter at:

National Weather Service Glossary of Abbreviations