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Area forecast discussion 
National Weather Service San Francisco Bay area
447 PM PDT sun Oct 4 2015 upper low has exited south of our area today. An
upper level ridge will develop over California early in the week
and then strengthen late in the week. This will result in dry and
warming conditions through the upcoming weekend.

&& of 2:45 PM PDT Sunday... satellite imagery shows
mostly clear skies from Oregon southward through Big Sur as a cool
dry air mass is left lingering over a large area in the wake of an
anomalously energetic upper low. Water vapor imagery shows the
driest air mass extends over the coast from the California Oregon
border southward through most of Baja California California. This region is
on the backside of the aforementioned 557dm upper low and
accompanying cold front which pushed through the area last
evening/overnight. In case you missed it... the top gust from
yesterdays system was 62mph at Altamont. Montana Diablo peaked at 59
miles per hour and sfo Airport gusted to 48 miles per hour. The top precipitation
observations was 0.20" at Napa Airport whereas most other
locations reported just a few hundredths or less.

The lightning detection network is picking up a large number
(thousands) of lightning strikes over the southern Sierra Nevada
and Death Valley region of the state below the northeastern sector
of the upper low. This is well outside of our forecast area... but
the most interesting phenomenon occurring across California this

For our forecast area.... a few storm cells are attempting to
rotate into extreme southeastern Monterey and San Benito
counties... however these cells are dissipating as they are
entrained by the more stable air mass within northwest sector of
the upper low... and further inhibited by the downsloping effects
encountered by traversing the complex terrain near Pinnacles
National Park.

For the week ahead... onshore flow will keep temperatures near
current levels for the next few days. Then an eastern Pacific
Ridge will shift downstream and strengthen over California at a
leisurely rate. This will lead to a gradual warming and drying
trend for the area beginning midweek and lasting through the
upcoming weekend. The warmest temperatures are expected late in
the week and early weekend when onshore flow dwindles or reverses
and subsidence aloft increases. Initial model data suggests highs
will be 5 to 10 degrees above normal for Friday and Saturday. The
ridge is flattened by early nex week an approaching shortwave
arrives from the northwest. This shortwave is currently modeled
to deflect back into the Pacific northwest region as the ridge
weakens over California... which will likely leave the area dry
for at least the next 7-10 days.

&& of 4:45 PM PDT Sunday...dry northeast flow over the
area will keep VFR conditions over the sfo and mry Bay area
through Monday. Patchy fog/ceilings in the inland valleys possibly
impacting sts.

Vicinity of ksfo...VFR.

Ksfo bridge approach...VFR.

Monterey Bay area terminals...VFR.

&& of 02:08 PM PDT Sunday...winds have subsided over the
area this morning as the low pressure system that brought the
strong winds to the area yesterday continues to move toward
Southern California today. Northwest winds will continue through
today but at much lighter speeds. High pressure will build over
the coastal waters and bays through the week.


Mtr watches/warnings/advisories...


Public forecast: drp
aviation: west pi
marine: Sims

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