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Area forecast discussion 
National Weather Service San Francisco Bay area
858 am PDT Tuesday Jul 7 2015

Synopsis...look for continued widespread night and morning low
cloudiness...along with some patchy fog and local coastal drizzle.
An upper low off the coast will move inland late Wednesday.
Associated upper level moisture may produce isolated showers and
thunderstorms in the Wednesday evening through Thursday night time
frame. Temperatures through the week will generally be near
normal.

&&

Discussion...as of 08:55 am PDT Tuesday...the marine layer
remains very disorganized compared to previous days and resulted
in less extensive cloud cover over the region this morning. The
low clouds that did develop inland overnight will likely burn-off
quickly this morning and give way to mostly sunny conditions. In
addition...temperatures region-wide are generally in the 60s this
morning and will warm into the 70s and 80s inland...while coastal
areas peak in the upper 60s to lower 70s. With that said...no
changes are needed to the short-term forecast at this time.

&&

Previous discussion...as of 3:00 am PDT Tuesday...clouds are
returning to the coast overnight and have filtered into some of
the adjacent valley locations. Fort Ord profiler is very
interesting today and has gone from a solid 2000 feet or so the
past couple of days to a very unorganized almost mixed out layer
this morning. Will be interesting to see how it changes today. The
poorly defined marine layer is likely one of the reasons that
there are currently some breaks in the clouds. However...surface
gradient is 3 mb from the west and about 1 mb from the north so
look for clouds to make is farther inland by sunrise.

Synoptically conditions are similar to yesterday with an upper
level low to our west forecast to remain fairly stationary at
least through today. Clouds should burn-off fairly fast with sunny
conditions in most spots expected by noon. Highs will be in the
middle 60s to middle 70s at the coast with middle 70s to middle 80s for most
inland spots.

The upper level low will finally progress to the east and be
overhead on Wednesday. At the same time conditions will become
more unstable with lifted values forecast to lower to around zero
and MUCAPE numbers locally over 250 j/kg. Models have slightly
backed off on convection compared to previous runs however with
the position of the low and some instability present will keep the
mention of possible showers and thunderstorms going. Models do indicate
coastal drizzle both Wednesday and Thursday morning which seems
reasonable given the expected pattern.

The low will quickly lift to the northeast the second half of
Thursday leading to the end of any showers. It will then be
replaced by a longwave trough extending down most of the coast.
Precipitation is not anticipated although the trough will keep temperatures
running near normal. A few inland spots will likely be cooler than
normal.

Longer range outlook out to July 20th sows little change in the
pattern with temperatures forecast to be near normal with generally dry
conditions.

&&

Aviation...as of 4:30 am PDT Tuesday...upper level low off the
coast will support a deep marine layer through today. Normally
this would mean a late burnoff time. However the feet Ord profiler
shows the marine layer becoming less defined. That and southerly
flow aloft will act to burn the stratus out of the sfo Bay area
earlier. Sfo and the approach forecast to burn off around 18z but
confidence is not high as many factors are involved for and
against the stratus.

Vicinity of ksfo...MVFR through 18z. West winds gusting to 24 knots
after 20z.

Ksfo bridge approach...similar to ksfo.

Monterey Bay area terminals...MVFR through 18z.

&&

Marine...as of 5:00 am Tuesday...low pressure off the California
coast will keep light winds through the week. The low will move
across the coastal waters Thursday bringing a slight chance of
thunderstorms.

&&

Mtr watches/warnings/advisories...
... Bay from 2 PM

&&

$$

Public forecast: rgass/Bell
aviation: west pi
marine: west pi



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