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Area forecast discussion 
National Weather Service San Francisco Bay area
1110 am PDT Tuesday Jun 30 2015

Synopsis...hot weather is expected today and Wednesday...especially
across inland portions of the forecast area as high pressure
builds over the western United States. Moisture will also make its
way toward our area Thursday which could also lead to a few
showers and thunderstorms.

&&

Discussion...as of 10:43 am PDT Tuesday...the current visible
satellite image is showing a solid stratus field over the coastal
waters with mostly sunny skies over the cities. Scattered high
clouds associated with some monsoon moisture are also passing over
the area. The current satellite water vapour image is showing
moisture rotating around a strong area of high pressure centered
over Utah. In addition to this synoptic feature a low pressure
system is present in the Gulf of Alaska.

The 1200z gfs40 and 0000z European model (ecmwf) have initialized well with the
current synoptic pattern and remain in good agreement through the
Holiday weekend. Both models build a dome of high pressure over
the western states which will promote hot temperatures across the
inland areas of our County Warning Area. 850mb temperatures over the inland
portions of the County Warning Area are expected to reach 25 to 26 c today warming
to 26 to 27 c on Wednesday. With light winds beneath the dome of
high pressure and these hot 850mb temperatures expect surface
temperatures to reach the upper 90s to 108 in some inland
locations. Therefore...have issued a heat advisory for the North
Bay area...East Bay area and the Santa Clara Valley valid today
into Wednesday. A gentle sea breeze will maintain comfortable
temperatures at the coast.

Temperatures are expected to cool a few degrees by Thursday as the
center of the dome of high pressure shifts to the northwest. With
the repositioning of the high a shot of monsoon moisture will
push into the area Thursday bringing up the possibility of showers
and isolated thunderstorms. The night crew added this possibility
to the forecast and the timing and location seems reasonable at
this time.

For the Holiday weekend it looks like the center of the high will
shift back towards The Four Corners states...bringing cooler
temperatures to the forecast area. Along with the cooler
temperatures expect a return of the marine layer at the coast.

&&

Aviation...as of 11:10 am PDT Tuesday... strengthening high
pressure over the area leading to widespread VFR conds with
lighter winds than yesterday. Shallow marine layer this morning
should further dwindle for tonight and Wednesday night. Not
expecting marine layer to return inland significantly until late
into the week or through the weekend... with exception of very low
IFR to LIFR ceilings just along the coastline...including
kmry...khaf...kwvi. Otherwise... just few to scattered high clouds
rotating in from the southeast around the Desert Southwest ridge.

Vicinity of ksfo... VFR. Onshore winds to 15 knots this afternoon. Do
not expect low ceilings tonight.

Ksfo bridge approach... same as terminal.

Monterey Bay area terminals... VFR this afternoon. Very low ceilings
with shallow marine layer tonight... with LIFR ceilings returning
after 02z... and LIFR visby/ceilings possible between 12 to 16z Wednesday.

&&

Climate...record highs for June 30 and July 1 for selected
locations.

Sf Bay area.................June 30............July 1
Kentfield..................106/1972...........103/1996
San Rafael..................98/1999............99/1991
Napa.......................105/1972...........103/1972
San Francisco...............93/1996............92/1991
sfo Airport.................92/1996............99/1985
Oakland downtown............90/1972............92/1984
Oakland Airport.............90/1950............90/1985
Richmond....................91/1996............97/1985
Livermore..................112/1972...........110/1950
Mountain View...............91/1972............97/1985
San Jose...................100/1996...........102/1985
Gilroy......................98/1999...........108/1972

Monterey Bay area............June 30............July 1
Monterey....................89/1996............96/1985
Santa Cruz..................98/1996............99/1970
Salinas.....................94/1996............85/1996
Salinas Airport.............97/1996............88/1991
King City..................109/1950...........105/1985

&&

Marine...as of 11:03 am PDT Tuesday...northerly winds gradually
decrease today from south to north with some gusty winds lingering
north of pt Reyes into the evening. Winds will continue to
decrease Wednesday through Friday as the weather pattern shifts. A
weak disturbance will move through the region on Thursday bringing
a chance of showers and thunderstorms to the region.

&&

Mtr watches/warnings/advisories...
... Advisory...North Bay area...East Bay area and the
Santa Clara Valley.
Small Craft Advisory...pt Arena to pt Reyes 0-10 nm
Small Craft Advisory...pt Arena to Pigeon pt 10-60 nm
Small Craft Advisory...sf Bay from noon

&&

$$

Public forecast: Larry
aviation: drp
marine: drp
climate: Bell



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