Scientific Forecaster Discussion
fxus66 kmtr 290359
Area forecast discussion
National Weather Service San Francisco Bay area
859 PM PDT Tue Mar 28 2017
Synopsis...a gradual warming trend will continue through
Wednesday as high pressure builds over the region. Cooler and
breezy conditions return on Thursday as a cold front sweeps
through the region. While a few light rain showers will be
possible, most locations will remain dry. The ridge will then
rebuild back over the region late in the week resulting in another
warming trend heading into the upcoming weekend.
Discussion...as of 8:59 PM PDT Tuesday...temperatures finished
off the day an average of 10 degrees warmer than yesterday across
most locations. Highs topped out in the 60s to mid 70s this
afternoon...about 5 to 10 degrees above average under sunny skies.
High pressure situated over the eastern Pacific will continue to
ridge across northern California this evening resulting in
continued dry weather, clear skies and moderate to locally gusty
winds across the district. Windiest location persist across the
north and East Bay mountains as well as select locations along the
coastal ranges. Temperatures will continue to climb Wednesday as
high pressure prevails. Highs in the mid 60s and 70s with a few
lower 80s expected in the afternoon.
A shift in the pattern is expected late Wednesday night as an
upper level low approaches from the north. The low and associated
cold front will then slides south across the region bringing a
slight chance of precipitation and cooler temperatures to the
area. Models continue to indicate that the greatest rain chances
will remain to the east with only a slight chance over the
forecast area for late Wednesday night into Thursday. Gusty winds
are also expected to accompany this system with strongest winds
anticipated over elevated terrain of the north and east bays as
well as along the coastal ranges. Breezy conditions will continue
into Friday with our local high resolution model indicating a
period of strong northerly winds late Thursday night into Friday
morning in the wake of this system. Strongest winds are expected
between 09z-15z Friday and will again impact the north and East
Bay mountains as well as the coastal ranges with coastal waters
also being impacted. Slightly warmer temperatures are expected
From previous discussion...high pressure is forecast to rebuild
back across the region late Friday into the upcoming weekend. As a
result, inland areas will rebound back into the 70s and lower 80s
with mostly sunny skies. Medium range guidance suggest dry
weather and seasonably mild temperatures will persist into early
next week as well with the ridge aloft. While confidence this far
out remains low, the models do hint at the potential return to a
wetter pattern late next week.
Aviation...as of 5:28 PM PDT Tuesday...near high confidence VFR
persists for the evening hours. Late afternoon visible imagery as
well as 24 hour trends indicate warmer and drier conditions all
supporting ongoing vfr; it's a gorgeous Spring day out there.
While there's presently an absence of coastal stratus and/or fog
lower level inversions are strengthening under mid-upper level
ridging and there could be a more organized stratus and/or fog
pattern visiting the coastline as early as Wednesday afternoon
and evening. This would precede the passage of a cold front
Thursday morning thus an intrusion of stratus and/or fog is
increasingly likely from later Wednesday evening into Thursday
morning. Just a heads up, following taf cycles may need to include
more in the way of cigs.
Vicinity of ksfo...westerly winds 20 to near 30 knots til 05z then
lighter westerly winds forecast for the remainder of tonight. Gusty
westerly winds resume on Wednesday. VFR.
Sfo bridge approach...similar to ksfo.
Monterey Bay terminals...westerly winds occasionally gusting to near
20 knots early this evening, lighter winds quickly returning thereafter.
VFR except possibly could see local MVFR cigs near sunrise Wednesday,
otherwise it looks favorable for VFR in 00z taf cycle. Stratus and/or
fog are possible Wednesday evening and night.
Marine...as of 4:41 PM PDT Tuesday...moderate and gusty northwest
winds will continue through the next several days as high pressure
strengthens over the eastern Pacific and tightens the pressure
gradient along the central coast of California. Northwest swell
will slowly decrease some tonight and will continue to through
about Thursday morning before building again late Thursday and
through the weekend.
... Arena to pt Reyes 0-10 nm
Small Craft Advisory...pt Reyes to Pigeon pt 0-10 nm
Small Craft Advisory...Pigeon pt to pt pinos 0-10 nm
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm
Small Craft Advisory...pt Arena to Pigeon pt 10-60 nm
Small Craft Advisory...Pigeon pt to pt Piedras Blancas 10-60 nm
Small Craft Advisory...rough bar advisory for sf bar
Small Craft Advisory...mry Bay until 9 PM
Public forecast: CW
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