Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service San Francisco Bay area
440 am PDT Thursday Apr 24 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 2:55 am PDT Thursday...satellite imagery shows
some low clouds over the coastal waters and extending into portions
of Marin and Sonoma counties. High clouds are starting to enter
into northern Sonoma County as well. Temperatures and dew points
are running higher than yesterday at this time. With this head
start...as well as weakening high pressure remaining over the area
..another mild day is on tap for the district with highs expected
in the 60s and 70s.
An upper trough off the Pacific northwest will drop southeast
into northern California tonight bringing a chance of rain to the
North Bay late tonight and into the rest of the district Friday.
The upper low center is still forecast to move across central
California late Friday thus thunderstorm chances are still
warranted. The trough is forecast to move quickly eastward with
showers ending by Saturday morning. Another weaker system is
forecast to move across late Saturday night into Sunday...but
rain chances are expected to remain from about the Bay area north.
High pressure is then prognosticated to build in strongly over the
eastern Pacific and onto the coast. This will bring in dry weather
and warmer temperatures through the rest of the work week. Highs
by Tuesday and Wednesday could push into the 90s across the
warmest inland sections of the district.
Aviation...as of 4:35 am PDT Thursday...mostly clear skies are
being reported around the forecast area this morning. GOES-west MVFR
probability image is showing stratus along the coast this morning.
This makes sense since Halfmoon Bay is reporting bkn013 at this
hour. The Fort Ord profiler is indicating a very shallow marine
layer less than 200 feet deep with a fairly well mixed atmosphere
above. Therefore...stratus is not expected to impact the Monterey
and Salinas terminals tonight. In the sf Bay area the sql sodar
does show evidence of a marine layer approximately 1000 feet deep.
Therefore cannot rule out stratus as a sun rise surprise for koak
Vicinity of ksfo...VFR is expected to prevail this morning with a
slight possibility of stratus impacting the terminals tempo
2412/2416 bkn005 bkn012. MVFR is anticipated by 0300z with a light
shower. West winds will increase to 15 to 20 knots this afternoon
with gusts to 25 knots possible.
Confidence is moderate
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR is expected this morning with
MVFR expected to begin around 0300z. Light showers are anticipated
to begin around midnight. Winds will increase out of the west this
afternoon reaching 10 to 15 knots.
Confidence is high
Marine...as of 04:39 am PDT Thursday...generally light west to
northwest winds will prevail along the central coast into the
weekend. However...winds will be locally stronger south of Point
Sur through tonight. A mixed swell will enter the coastal waters
Friday featuring a moderate sized medium period westerly swell and
a long period southerly swell. The mixed swell will last into the
... Francisco Bay north of the Bay Bridge from 2 PM
Small Craft Advisory...San Francisco Bay south of the Bay Bridge from 2 PM
Small Craft Advisory...Monterey Bay from 2 PM
Small Craft Advisory...Pigeon pt to pt pinos 0-10 nm from 2 PM
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm
Small Craft Advisory...pt pinos to pt Piedras Blancas 10-60 nm
Public forecast: Sims
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