Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
FXUS66 KMTR 251217
Area Forecast Discussion
National Weather Service San Francisco Bay Area
517 AM PDT Tue Apr 25 2017
.SYNOPSIS...Dry weather with comfortable temperatures can be
expected today. Another chance of rain, mainly over the North
Bay, is slated for Wednesday, with dry and seasonably cool weather
expected elsewhere. Dry weather along with a warming trend is
forecast across the region from Thursday through the weekend as
high pressure builds in. Breezy conditions are likely from
Thursday and Friday, especially in the hills.
.DISCUSSION...as of 3:10 AM PDT Tuesday...Showers moved completely
out of our CWA yesterday evening with mostly clear skies now for
most the area from SF southward. Satellite does show higher clouds
over the north bay. Temperatures will be a degree or two warmer
compared to yesterday -- mostly 60s to lower 70s.
Synoptically a system will move into the Pac NW on Wednesday with
the far southern edge of moisture forecast to possibly go across
the North Bay. Guidance has been trending slightly drier compared
to yesterday with a chunk of the models keeping virtually our
entire area now dry. Amounts will be minor -- less than a tenth
for most of the North Bay with little to no accumulations
forecast for SF Bay southward. In fact, totals may be close to
what we saw from the system on Monday.
A substantial change in the pattern will begin to take shape on
Thursday as a ridge of high pressure aloft beings to build toward
the coast. At the same time off to our east the flow will become
tighter and northerly as a system drops into the central Conus
from Canada. The amplification will continue to increase Friday
into Saturday as an upper low dives into the Four Corners Region.
Winds will increase with breezy conditions likely Thursday into
Friday. Models have backed off a bit compared to previous runs, so
a little less concern for fire weather interests compared to 12
Closer to the surface a ridge of high pressure will move to our
region leading to warmer temperatures especially by the weekend.
Highs on Saturday and Sunday will be in the 70s to mid 80s for
most spots away from the coast. Should be enough of a sea breeze
to keep many beaches and locations right at the coast in the 60s
to lower 70s. Any rain chances will be well to our north.
The ridge will slowly advance to the coast and then flatten and
progress off to the east next work week. The storm track will stay
well to our north with warmer than normal temperatures likely.
.AVIATION...as of 05:15 aM PDT TUESday...Predominately VFR after
some lower cigs earlier in the night. Look for few-sct cloud decks
in the lower to upper levels today as moisture streams in from the
northwest aloft. Breezy northwest winds in favored valleys, over
higher terrain, and along the coast through the day today with
gusts 20-25kt possible. Low CIGS return tonight.
Vicinity of KSFO...VFR with breezy, occasionally gusting to 25 kt,
west winds today. FEW-SCT cloud decks through low to high levels
through the day... with increasing low clouds overnight tonight.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...VFR. Afternoon sea breeze. Lower cigs
.MARINE...as of 05:11 AM PDT Tuesday...High pressure off the coast
will lead to breezy west to northwest winds with locally stronger
winds along the Big Sur coast. Winds and seas will increase
Wednesday night into Thursday as high pressure strengthens over
the eastern Pacific resulting in a tighter pressure gradient
across the coastal waters.
.Tday...SCA...Mry Bay from 9 AM
SCA...Pigeon Pt to Pt Pinos 0-10 nm from 9 AM
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
PUBLIC FORECAST: Bell
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