Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
1033 am PDT Tuesday Oct 6 2015
Synopsis...dry weather conditions will persist along with a
gradual warming trend through late week as high pressure builds
over the California coast.
Discussion...as of 8:35 am PDT Tuesday...more clouds this morning
compared to yesterday although with a few patches already
indicated, it should burn-off fairly fast. Highs today will be
similar to yesterday with most spots in the middle 60s to upper 70s.
A few 80s are possible well inland.
A ridge of high pressure will build back to our region as the week
progresses. This will allow temperatures to slowly warm back to above
normal levels. Friday and Saturday should be the warmest for most
locations. In general highs will be 7 to 12 degrees warmer than
what we will see today.
Various computer models (both operational and ensemble) show
virtually all moisture associated with hurricane oho to remain to
our west and north through the weekend although a few sprinkles
cannot be entirely ruled out for the North Bay. Will probably put
in a slight chance with the afternoon package.
Other issue of concern is the possibility of subtropical moisture
returning to our area next week as the models bring a moist flow
toward our County Warning Area from the southeast. This is still at least a week
out, however will need to be closely monitored especially due to
fire weather concerns.
Previous discussion...an upper level low remains centered over
far southeastern California this morning and is forecast to slowly
shift east- southeast through midweek. Meanwhile...an upper level
ridge will continue build on along the California coast and result
in a warming and drying trend through late week. By Friday...the
ridge is forecast to peak above 590 dam with temperatures back
above average. 70s to lower 80s will be likely near the coast with
80s to lower 90s over inland areas.
The ridge is then forecast to flatten by the upcoming weekend as
a series of middle/upper level systems push into the Pacific
northwest and British Columbia. This will allow temperatures to
cool slightly...yet remain above seasonal averages. The GFS and
Canadian both bring a frontal boundary down into the San
Francisco Bay area late Saturday into Sunday...even showing light
amounts of precipitation. Meanwhile...the European model (ecmwf) keeps conditions
dry across our region. In addition...the models show the current
middle/upper level cut-off low over Southern California retrograding
back off of the Baja California California coast this weekend and slowly
moving northward into early next week. This could spread middle-level
moisture back over Southern California. With all that said...will
keep dry conditions in the forecast at this time given the lack of
consistency in the medium range models. Regardless...a few
features Worth watching in the coming days.
Aviation...as of 10:29 am PDT Tuesday...VFR this afternoon and
this evening for most terminals. The only potential hiccup are low
stratus lurking near Monterey. Will have to monitor.
Otherwise...ample stratus remains off the coast and will likely
come inland tonight with IFR to MVFR conditions at most locations.
Overall conf is medium.
Vicinity of ksfo...VFR conditions. Winds may be briefly NE...but
should switch west to northwest this afternoon. Ceilings return tonight...but
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR this afternoon...but ceilings return
shortly after 00z this evening.
Marine...as of 10:29 am PDT Tuesday...southerly winds will
continue across the coastal waters as high pressure remains off
the Southern California coast. Gusty winds are possible this
afternoon and evening over the San Francisco Bay north of the Bay
Bridge. Otherwise generally light winds and seas are expected
through midweek...then modestly increasing through the second half
of the work week. Southwesterly swell up to 2 feet will mix with
northwesterly swell this week.
... Bay from 2 PM
Public forecast: Bell
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