Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
FXUS66 KMTR 300059
Area Forecast Discussion
National Weather Service San Francisco Bay Area
559 PM PDT FRI JUL 29 2016
.SYNOPSIS...Typical summertime conditions will continue over the
next several days with clouds and cooler temperatures near the
coast with warmer weather inland. A cooling trend is slated to
begin during the weekend as an upper level trough approaches the
west coast. Smokey conditions will continue over portions of
Monterey Bay to the South Bay.
.DISCUSSION...as of 2:30 PM PDT Friday...Very similar conditions
to yesterday with around a 2 MB onshore flow combined with a 1000
foot marine layer lead to a wide range in temperature. Coastal
locations at this hour are in the upper 50s to lower 70s with
inland spots generally in the 80s and 90s. 24 hour change product
shows most locations are within 2 degrees of yesterday. Main item
of note remains the Soberanes fire with its very visible presence
on satellite. Smoke can be seen extending to the north and
northeast into a large portion of the Monterey Bay Region.
Forecast wise, minor cooling can be expected over the next several
days as a longwave trof approaches the west coast. This will help
to increase the onshore flow and bring higher humidity values to
our region. The biggest impact will be for inland spots that have
been the hottest. Temperatures there will see a 5 to 10 degree
drop by Sunday and Monday compared to today.
Longer range forecast indicates little change through the
remainder of next week and possibly longer with a weak zonal flow
in place aloft and a continual onshore flow at the surface.
Temperatures should average near normal for the period.
.AVIATION...as of 5:58 PM PDT Friday...A strong mid-upper level
high center will remain stationary near KLAS while a weak and dry
surface-mid level low develops over the EPAC and overlaps the
coastal waters tonight and Saturday. On/off SMX-SFO gradient in
recent days peaking 1 to 2 mb each afternoon and evening is
currently 1.8 mb. The NAM model forecasts slight increases in
surface ridging over the Central Coast through Saturday night
likely furthering the SMX-SFO gradient leading to a southerly wind
reversal over the inner waters during this period. Southerly flow
aloft is also forecast to persist transporting smoke layers to the
Bay Area and Central Valley. The marine layer is 1,000 feet deep;
stratus and fog also mixed with areas of smoke on the north Central
Coast are likely to stay confined to the immediate coast with onshore
winds resulting in marginal late night and morning intrusions into
the San Francisco Bay and northern Salinas Valley.
Vicinity of KSFO...W-NW winds gusting to 20-25 knots until 04z
then lighter westerly winds forecast tonight. Moderate-high
confidence VFR. Gusty westerly winds resume Saturday afternoon and
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...VFR then IFR/LIFR this evening and overnight
as stratus and fog fill in over the area on light onshore winds.
MVFR/VFR returns by late Saturday morning.
.MARINE...as of 07:59 AM PDT Friday...High pressure over the
eastern pacific coupled with a thermal trough along the coast will
maintain light to moderate northwesterly winds across the coastal
waters. strongest winds will remain over the northern outer waters
and north of the bay bridge. a mixed swell will continue across
the coastal waters.
.Tngt...SCA...SF Bay until 11 PM
PUBLIC FORECAST: Bell
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