711
FXUS66 KMTR 231757
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco Bay Area
957 AM PST Sun Feb 23 2020
.SYNOPSIS...Low clouds and onshore flow will persist through the
morning with continued cool high temps today. Dry and warmer
conditions will return throughout most of the week as high
pressure builds over the state.
&&
.DISCUSSION...as of 08:39 AM PST Sunday...For portions of the Bay
Area this morning it may feel more like summer than winter. Deep
stratus is covering some of the inland valleys making it feel damp
and cool. In fact, there have been numerous reports of drizzle.
The ground was wet here at the forecast office in Monterey. Clouds
will be somewhat slow to clear this morning, but once they do it
will be a cool and pleasant Sunday afternoon. Highs today will
generally be in the 60s.
No update needed at this time.
&&
.PREV DISCUSSION...as of 2:21 AM PST Sunday...A warming trend
will begin on Monday and continue through the week as a ridge of
high pressure builds over the state and weak northerly to offshore
flow develops. High temperatures are forecast to be in the upper
60s to upper 70s, and overnight lows in the 40s through much of
the week.
Medium range models continue to hint at rain chances a week from
today when an upper low drops south from the Gulf of Alaska and
then onshore over Southern California. More than a few ensemble
members of both the GFS and the ECMWF indicate measurable rain on
next Sunday, and at times throughout the following week. Keeping
fingers crossed.
&&
.AVIATION...as of 9:59 AM PST Sunday...for 18Z tafs...Field of
stratocumulus across the coastal waters and inland from
essentially KSFO-KOAK in the north to KMRY-KSNS in the south.
Upstream feed looks sufficient to bring at least SCT/BKN to
KSFO/KOAK through 1930-2000Z before becoming mostly clear through
the afternoon. For KMRY/KSNS there is potential to see BKN cigs
through the day as the discontinuous upstream feed is expected to
persist through the day. A steeper onshore gradient today will
bring breezy to occasionally onshore winds near the coast,
particularly later this afternoon to early evening. Then,
significant shift for the overnight forecast for the Bay Area taf
sites-- the local and national wrf show increasingly offshore
winds overnight, rapidly drying the mid to lower layers. Could see
some lower level FEW-SCT potentially even BKN form early in the
evening then gradually lower/mix out to become FEW/SKC by sunrise
Monday. Farther south, the Monterey Bay terminals could be locked
in to gradually lowering OVC-BKN overnight, with -DZ posbl. Mostly
clear skies for southern terminals by mid morning Monday.
Vicinity of KSFO...SCT-BKN cigs at or around 1600-2200 ft thru
1930-2000Z. Breezy,occasionally gusty, onshore winds through the
early evening. Could see some low clouds arrive this evening
before winds shift offshore overnight and dry out the mid to lower
layers. Medium confidence of VFR tomorrow morning.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...Most models suggest KMRY and potentially
KSNS will be under clouds through most the day even if satellite
imagery shows quite a discontinuous feed. May see intermittent
sunlight but feed upstream is robust enough could definitely see
this play out. Thus, MVFR cigs thru the day, with breezy onshore
winds. For tonight, -DZ with OVC IFR-LIFR cigs, clearing tomorrow
morning around 17Z.
&&
.MARINE...as of 09:48 AM PST Sunday...Moderate, locally gusty,
northwest winds today through early next week before easing mid
week. Moderate northwest seas. A long period northwest swell
arrives mid week.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tday...SCA...Pt Reyes to Pigeon Pt 0-10 nm
SCA...Pigeon Pt to Pt Pinos 0-10 nm
SCA...Pt Arena to Pt Reyes 0-10 nm
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
SCA...Pt Arena to Pigeon Pt 10-60 nm
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
SCA...Mry Bay
&&
$$
PUBLIC FORECAST: MM/Sims
AVIATION: DRP
MARINE: DRP
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