FXUS66 KMTR 161155
Area Forecast Discussion
National Weather Service San Francisco Bay Area
455 AM PDT Wed Aug 16 2017
.SYNOPSIS...Temperatures will warm through the week as a ridge of
high pressure builds into our region. Clouds can be expected ever
night especially for locations near the coast.
.DISCUSSION...as of 3:00 AM PDT Wednesday...Another round of
widespread clouds overnight with virtually all urban locations
seeing clouds at this hour. Surface gradient has gone directly
from the west around 1.5 MB with a marine layer still over 2000
feet, so most spots will be cloudy through the morning hours. By
afternoon should see burn-off toward the coast. A ridge of high
pressure that is slowly building toward our region will help to
push temperatures up a few degrees especially well away from the
coast. Highs will generally be in the 60s at the coast with 70s
and 80s inland. Far eastern spots will go into the lower 90s.
Temperatures will trend warmer the next several days as the
ridge continues to progress toward our region. At the same time
850 MB temperates will warm 1 to 2 C each day. Highs will return
to warmer than normal levels for far inland spots with mid 80s
to upper 90s likely. However, elevated heat risk levels will
generally remain low. At the coast a continued onshore flow with
waters in the upper 50s to lower 60s will keep temperatures on the
An upper level low will drop into our region by next work week.
This will lower inland highs, however it could lead to more
disruption to the stratus which would mean more sunshine at the
.AVIATION...As of 4:50 AM PDT Wednesday... Marine layer reacting
to East Pacific ridge building towards coast by thinning by at
least 1500 feet since yesterday morning. Cloud bases at or around
1400-1800 feet this morning may drop another 100-200 feet through
the early morning, with tops 2400-2600 feet. KSTS is IFR while
other sites are MVFR. Key difference is the slope of warmer air
above the marine layer from north to south. Thinner marine layer
will mix burn off quicker than yesterday as reflected in the TAF.
This trend continues into tomorrow, with continued compression and
thinning of the marine layer with warm air advection at the top
of the marine inversion. Otherwise, light to breezy onshore winds
(strongest in the afternoon).
Vicinity of KSFO...Light onshore winds becoming breezy in
afternoon. MVFR cigs will linger until at least 16Z-17Z.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...MVFR cigs through most of the day around
the lip of the bay with some brief midday clearing. Light to
occasionally breezy onshore winds by the afternoon.
.MARINE...as of 04:47 AM PDT Wednesday...East Pacific ridge builds
towards the coast resulting in lighter winds overall. Some locally
gusty winds over the northern outer waters and northern San
Francisco Bay through the afternoon.
.Tday...SCA...Pt Arena to Pigeon Pt 10-60 nm until 9 AM
SCA...SF Bay from 9 AM
PUBLIC FORECAST: Bell
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