Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
342 am PST Tuesday Jan 27 2015
Synopsis...a weak upper level system will continue to move
across central California and bring light precipitation to
portions of the central coast through this afternoon. Dry weather
conditions and mild temperatures return Wednesday and persist into
the weekend as high pressure builds over the region.
Discussion...as of 03:19 am PST Tuesday...light rain being
reported across southern Monterey and San Benito counties early
this morning underneath a cloud deck generally above 5kft based
off recent automated observations. This precipitation is a result
of a weak middle/upper level low pressure system that continues to
move northward across southern and central California. While middle-
level moisture continues to advect northward over the region this
morning...the lower levels of remain relatively dry. Given
this...expecting precipitation to remain light especially given
the weak middle/upper level support associated with the system. The
latest model analysis shows the upper low already becoming more
disorganized at this hour and is forecast to become an open wave
later today as it begins to shift toward the northeast. Aside
from lingering showers through the early afternoon...precipitation
chances quickly drop off later today as the system pulls away from
Another weak middle/upper level trough and associated low pressure
system is forecast to undercut the larger scale ridge and
approach Southern California later this week. The models
generally agree this system will stay well enough to our south
and will lack needed moisture/support to bring precipitation to
our region. Thus...dry weather conditions will persist through
the remainder of the work week as the ridge off of the West Coast
The ridge aloft will then nose into northern California during
the upcoming weekend and bring a warming trend back to the
Monterey/San Francisco Bay area. Daytime temperatures will likely
warm into the upper 60s to 70s once again by Saturday and Sunday.
These above average temperatures and dry conditions will likely
persist at least into the beginning of next week.
Aviation...as of 3:42 am PST Tuesday...middle and high level clouds
will continue to stream across the region today as a weak weather
system moves over the central coast. Mainly VFR conditions are
expected through the forecast period. Light and locally variable
winds will prevail.
Vicinity of ksfo...VFR. Light winds.
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR. Light winds.
Marine...as of 2:06 am PST Tuesday...a weak weather system
moving across the region will result in light southerly winds
across the coastal waters. By midweek high pressure will build off
the northern California coast bringing light to moderate northwest
winds to the coastal waters for the second half of the week.
Public forecast: rgass
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