Scientific Forecaster Discussion
fxus66 kmtr 270550
Area forecast discussion
National Weather Service San Francisco Bay area
1050 PM PDT Fri may 26 2017
Synopsis...temperatures will begin trending back to seasonal
norms as high pressure builds over the region. Dry and warmer
Sunday and Monday. Another trough begins to approach by Tuesday
and Wednesday with a modest cooling trend and continued coastal
Discussion...as of 8:59 PM PDT Friday...low clouds were slow to
clear today with widespread low clouds holding on through the
late afternoon. The last few frames of visible satellite imagery
shows only patchy low clouds clinging to the hills at this hour.
Low clouds are expected to return once again late tonight.
Confidence is low as to when the stratus will return however it is
likely to fill in along the coast and locally inland under a
slightly more compressed 2000-2500 ft marine layer. The shallower
marine layer will likely limit stratus intrusion inland compared
to what we have seen the last couple of days.
Temperature varied by only a few degrees today from yesterdays
high with most locations topping out in the upper 50s to lower
60s along the coast to mid to upper 60s around the bays and
inland. The warmest inland locations that were exposed to a bit
more sun late in the day reached into the low to mid 70s.
Below average temperature are expected to begin warming ever so
slightly Saturday to near normal temperatures as high pressure
begins building in over the region. The warming trend will really
take hold on Sunday and Monday of this Memorial Day weekend as 850mb
temps soar to around 18 degrees c and 500mb heights reach 582 dam
by Monday. The most noticeable warming will be felt inland with
temperatures reaching into the 80s to low 90s in the warmest
locations. Near the coast temperatures will be tempered by the
cool ocean influence with temperatures only warming to around 60
to the 70s near the bays.
Temperatures will cool by midweek as an approaching upper level
trough moves across the state resulting in a deepening marine
layer, patchy drizzle along the coast and a cooler airmass
settling in over the area. Models do not have a good handle on
this system and hence will hold off on any mention of precip at
High pressure is forecast to fill in behind the low as it shift
south and east through the later half of the week. Temperatures
are expected to rebound to seasonal averages Friday and into the
As always if you plan to travel over this Holiday weekend please
take time to visit weather.Gov for the latest forecast for your
Route and travel destinations.
Aviation...as of 10:45 PM PDT Friday...low clouds cleared from
most terminals on Friday evening. But significant moisture remains
in the boundary layer and so it's likely that most terminals will
develop MVFR ceilings overnight, continuing through much of
Saturday morning. VFR expected at all terminals by midday
Saturday. Light southwest winds overnight will turn to the west
and northwest on Saturday afternoon and increase.
Vicinity of ksfo...VFR early in period with MVFR ceilings likely
to develop overnight...most likely around 09z although confidence
is low concerning timing. Clearing expected to take place by
17-18z Saturday morning with VFR conditions for the remainder of
the day. Light westerly winds overnight, increasing Saturday
Sfo bridge approach...similar to ksfo.
Monterey Bay terminals...VFR early in period with MVFR ceilings
likely to develop by 08z and continue until 19z Saturday. Light
Marine...as of 08:05 PM PDT Friday...light westerly winds will
prevail along the coast through early Saturday. High pressure
will build over the eastern Pacific this weekend resulting in
increasing winds along with steeper wind waves.
... Bay from 3 PM
Small Craft Advisory...Pigeon pt to pt pinos 0-10 nm from 3 PM
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm from 3 PM
Public forecast: CW
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