Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
FXUS66 KMTR 251721
Area Forecast Discussion
National Weather Service San Francisco Bay Area
1021 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 08:37 AM PDT Tuesday...A mix of sun and
clouds across the region this morning as moisture continues to
advect inland ahead of an approaching system. Overall, should see
temperatures this afternoon near or slightly warmer than those
yesterday as any precipitation will likely stay north of the
region. However, can`t rule out very light rain over the far
northern portions of the North Bay through the day. Thus, will
keep the mention of precipitation across this area while the rest
of the region will remain dry. Have updated sky cover a bit to
reflect current trends with the greatest cloud cover likely across
the northern half of the region today while more sun can be
expected across the Central Coast. Otherwise, the ongoing forecast
remains on track for the short-term. Please see previous forecast
discussion below for additional details.
.PREV 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 10:19 AM PDT Tuesday...Mid and high level clouds
continue to stream in from the north ahead of the next system.
Expecting VFR today with breezy conditions. Cigs will gradually
lower overnight with -ra poss at KSTS early Wed, but will only do
VCSH for KOAK and KSFO.
Vicinity of KSFO...Little change from previous forecast. VFR
through today. MVFR cigs develop tonight/early Wednesday. A
passing shower poss early Wednesday.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...VFR. Afternoon sea breeze. Lower cigs
return tonight with MVFR category.
.MARINE...as of 10:17 AM PDT Tuesday...Moderate to locally strong
northerly winds will prevail as high pressure remains anchored off
the coast. The strongest winds will likely occur monterey bay
southward along the immediate coast. Winds and seas will increase
over all coastal waters on Wednesday as high pressure
.Tday...SCA...Pigeon Pt to Pt Pinos 0-10 nm
SCA...Mry Bay from 12 PM
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
PUBLIC FORECAST: RGass
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