Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service San Francisco Bay area
1059 PM PDT Wednesday Apr 23 2014
Synopsis...a storm system will bring cooler temperatures and
chances for precipitation to the region late Thursday night
through Friday. Another weaker system could bring rain chances to
northern California Saturday night and Sunday. Then high pressure
will bring dry and significantly warmer conditions to the area
Discussion...as of 9:30 PM PDT Wednesday...upper level ridge
brought dry and warmer weather to the area today. High temperatures
warmed up 3 to 6 degrees over yesterday. The ridge is starting to
flatten as a warm front approaches the Pacific northwest. High
clouds will spread over the area from the north tonight and
Thursday but under southwest flow aloft...high temperatures will
be near or slightly above todays highs.
An upper trough off the Pacific northwest will drop southeast into
northern California Thursday night bringing a chance of rain to
the North Bay late Thursday night and the rest of the district
Friday. Earlier today models were in good agreement with bringing
1/4-1/2 inches of rain to much of the district and rain chances
were looking good. But the latest NAM is much drier with only
scattered precipitation. The 00z GFS has also trended a little drier with
less precipitation amounts for the area. Will be interesting to see the
00z European model (ecmwf) as the European model (ecmwf) has outperformed the other models as of
late. So for now the rain forecast for Thursday night and Friday
remains in the chance category.
By Saturday morning the last of the showers will be out of the
southern end of the district. Saturday will be partly cloudy and
cool. Another system will move into the Pacific northwest on
Sunday with the tail end of the system bringing a chance of rain
to at least the northern part of the district. Any rain with this
system will be very light.
High pressure is the prognosticated to build over the west beginning on
Monday. This will bring dry conditions and warmer temperatures to
the district. Inland valley locations will easily warm into the
80s with some areas possibly hitting the lower 90s on Tuesday and
Aviation...as of 10:55 PM PDT Wednesday...patchy stratus is
beginning to form along the northern and central coast. Stratus
has not been as aggressive as earlier anticipated therefore have
pushed stratus onset back a few hours. Increasing high clouds are
expected to continue as an approaching cold front nears the West
Coast. West winds will continue to ease as the night progresses.
Vicinity of ksfo...VFR conditions expected through late tonight.
Will bring MVFR 11z over ksfo and 12z over koak. West winds
will continue to ease as the night progresses.
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR conditions expected through
tonight with MVFR ceilings expected tomorrow morning. Light winds
expected through the night.
Marine...as of 05:00 PM PDT Wednesday...west and northwest winds
will prevail along the central coast into the weekend. Winds will
be locally stronger along the coast...especially south of Point
Sur tonight and Thursday. A long period south swell entering the
coastal waters Friday night/early Saturday. Initially 2-3ft with a
period of 20 second...then 2-4ft with a period of 18-19 second on Saturday. The
south swell may get mixed out a little bit with a moderate northwest wind
and moderate northwest swell.
... Pinos to pt Piedras Blancas 0-10 nm
Small Craft Advisory...pt pinos to pt Piedras Blancas 10-60 nm
Small Craft Advisory...Monterey Bay until 11 PM
Small Craft Advisory...Pigeon pt to pt pinos 0-10 nm until 11 PM
Public forecast: west pi
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