FXUS66 KMTR 141712
Area Forecast Discussion
National Weather Service San Francisco Bay Area
1012 AM PDT Tue Aug 14 2018
.SYNOPSIS...Temperatures will be near to slightly below seasonal
averages through midweek as a modest marine layer and onshore flow
persist over the region. High pressure is then forecast to rebuild
toward the West Coast late in the week and into next week bringing
warmer temperatures to the interior.
.DISCUSSION...as of 09:10 AM PDT Tuesday...Satellite imagery this
morning shows extensive cloud cover for this time of year with a
marine layer at around 1,500 feet in depth. Thus, low clouds
spread well inland into just about all valley locations overnight
with patchy drizzle reported along many coastal areas as well as
into the East Bay Hills. Aloft, high level clouds can be seen as
well as mid/upper level moisture advects northward over the
region. Any convection at this time appears to be across the
interior portion of the state. Given the cloud cover, have lowered
temperatures by a few degrees for locations around the greater
San Francisco Bay Area. Otherwise, the rest of the forecast
appears on track this morning. For additional details, please see
the previous forecast discussion below.
.PREV DISCUSSION...as of 3:41 AM PDT Tuesday...Average temperatures
Monday were a couple to a few degrees below August 13 normals at
the coast, around the bays, and inland. Sea surface temperatures
at the buoys are presently 54 to 56 (except Half Moon Bay's 59 SST
appears a bit mild in comparison. Half Moon Bay's morning lows
back through August 1st have been chillier than the buoy's sea sfc
temp) At any rate onshore breezes continue this morning, it's
chilliest ocean side along with patches of drizzle while mostly
cloudy skies extend well inland from the coast. Clearing back to
near the immediate coast will return by afternoon. Onshore breezes
will help keep daytime temperatures tempered at or below normal
maximum temperatures today and likely again Wednesday.
A warming trend will commence later in the week as the high pressure
center over the southwestern U.S. eventually returns and rebuilds
over California. Temperatures will then warm back up to normal to
a few degrees above mid August normals with 80s/90s maybe 100 degree
mark inland, but sea-breezes should keep seasonably cool temperatures
going along the coast, over the weekend.
.AVIATION...as of 10:12 AM PDT Tuesday...for 18Z TAF package.
Widespread stratus continues to impact the area this morning with
MVFR/IFR ceilings reported at some point at all TAF sites. GOES-
East visible shows that the stratus pushed well inland, up to the
Pacheco Pass along the Santa Clara/Merced County line. Expect late
clearing compared to usual at the terminals today, with some
locations possibly remaining overcast into the afternoon hours.
Vicinity of KSFO...MVFR/IFR ceilings are expected to continue for
the next few hours, associated with a deep marine layer, before
transitioning back to VFR. The latest TAF package brings the
return of the stratus several hours earlier based on current
trends and guidance.
SFO Bridge Approach...Similar to the terminal.
Monterey Bay Terminals...MVFR/IFR ceilings expected for much of
the morning at both KSNS and KMRY. Could be one of those events
with KMRY maintaining overcast skies all day. Expect ceilings to
drop again in the evening hours and after sunset with IFR
conditions into Wednesday morning.
.MARINE...as of 09:10 AM PDT Tuesday...Light to locally moderate
winds will continue this afternoon over the coastal waters. The
northwest swell is forecast to remain light to moderate this week,
while the southerly swell will gradually increase through the
week and into the weekend.
.Tday...SCA...SF Bay from 2 PM
PUBLIC FORECAST: RGass/Canepa
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