Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
313 am PDT Wednesday Aug 5 2015
Synopsis...a modest warming trend is forecast for Wednesday and
Thursday as high pressure ridge builds over the region. Cooler
temperatures return late in the week along with a slight chance of
showers and thunderstorms Thursday night and Friday as an upper
level low approaches the region from the west. Drier and warmer
conditions are expected over the weekend.
Discussion...as of 3:00 am PDT Wednesday...stratus is once again
staying well away from the coast so only a few patches are
expected over the district this morning. An upper level ridge is
building over the area from the upper high over the southwest.
This will bring about 4 to 6 degrees of warming today and
High clouds will stream over the southern part of the district
today and spread north on Thursday ahead of a developing upper
level low currently about 700 miles west of Monterey. This low
is forecast to move inland across the County Warning Area on Friday. Increasing
instability and middle level moisture will bring a slight chance of
showers or thunderstorms from the Santa Cruz Mountains north
Thursday night and Friday. Cooler temperatures will also result.
The upper low will move out of the area Friday night and the
convective threat will end. For the weekend upper level troffing
will develop off the West Coast from an upper low approaching
British Columbia. This will keep temperatures near seasonal
normals with low clouds returning to the coast.
Aviation...as of 10:45 PM PDT Tuesday...a few areas of low clouds
are redeveloping near Point Reyes and middle/high clouds with the
sub-tropical jet stream continue to stream NE over the Bay area
and central coast. Otherwise VFR conditions prevail this evening.
The marine layer is absent on The Fort Ord and Bodega Bay profilers.
There's a little bit of warming actually showing up near the surface
due to proximity to warmer coastal waters. A gradual warming in the
lower to middle levels is forecast tonight and Wednesday as a ridge
develops over the area. However due to a lack of temperature
difference from the normally cooler ocean waters to warmer lower
levels stratus and fog coverage will likely be at a minimum during
Vicinity of ksfo...low to moderate confidence MVFR ceilings will redevelop
Ksfo bridge approach... similar to ksfo.
Monterey Bay area terminals...VFR conditions with mainly high clouds.
Light winds. Low to moderate confidence IFR redeveloping tonight.
Marine...as of 9:52 PM PDT Tuesday...mainly light winds will
continue over the coastal waters...but northwest winds will tend
to increase once again by late in the week. An upper level low
pressure area over the eastern Pacific will move over the coastal
waters Thursday into Friday with some shower or thundershower
activity possibly arriving by late in the day Thursday.
... Arena to pt Reyes 0-10 nm from 3 PM
Small Craft Advisory...Pigeon pt to pt pinos 0-10 nm from 3 PM
Public forecast: west pi
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