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Area forecast discussion 
National Weather Service San Francisco Bay area
1109 am PDT Friday Jul 29 2016

Synopsis...weakening high pressure aloft will result in another
very warm day today across inland areas, with seasonably cool
temperatures along the coast with continued weak onshore flow. A
cooling trend is slated to begin during the weekend as an upper
level trough approaches the West Coast.

&&

Discussion...as of 2:54 am PDT Friday...around a 1000 foot marine
layer this morning combined with a 2.3 mb onshore gradient at the
surface has lead to a typical summertime start with clouds at the
coast plus many adjacent valley locations. Smoke plume from the
soberanes fire is also easily detected via satellite with the
direction continuing to go southwest to northeast. Conditions
overall will be similar to yesterday with comfortable readings at
the coast while widespread upper 80s to the lower 100s can be
expected inland.

Latest model guidance in continues to show a wind shift more to
the south and southeast over the weekend as a longwave trough
approaches the West Coast. Will add additional smoke to the
weather grids out through at least the weekend around Monterey
Bay region. This will also lead to slightly improved humidity
recoveries for the overnight hours.

Previous discussion...satellite fog product is showing a similar
low-cloud pattern as yesterday at this time with a solid stratus
layer along the entire coastline and low clouds extending into the
Salinas valley. The heat signature from the soberanes fire is
still quite marked, showing up as dark pixels on a sea of light
gray.

Today is expected to be another hot day across inland areas, but
cooler temperatures are on the way. Highs today are forecast to be
similar to those on Thursday with hottest areas topping out around
107, but most inland areas more it the 80s and 90s, and 60s to
lower 70s along the coast. Beginning on Saturday the upper ridge
will begin to weaken as an upper level trough starts digging along
the north coast. As this trough deepens during the following days,
high temperatures are expected to decrease by 5 to 10 degrees
across the hottest inland areas, with less difference expected
along the coast.

&&

Aviation...as of 11:10 am PDT Friday... marine layer has
retreated offshore with VFR conditions reported across the area.
A wind shift over the soberanes fire will bring more smoke
northeastward today and especially into this weekend which could
once again bring a 3000-10000 foot layer of smoke to most taf
sites. Main impacts expected at ksns and potentially kmry due to
projected trajectory of the smoke and proximity to the fire.
Marine layer expected to gradually deepen and push further inland
through the weekend.

Vicinity of ksfo...VFR. Breezy onshore winds this afternoon.

Sfo bridge approach...same as terminal.

Monterey Bay terminals...smoke from the soberanes fire will
continue to linger aloft over the Monterey Bay area today with
transport winds blowing from the south. Vlifr-LIFR cigs/visbys
posbl after 02z as marine layer pushes inland and combines with
smoke condensation nuclei.

&&

Marine...as of 07:59 am PDT Friday...high pressure over the
eastern Pacific coupled with a thermal trough along the coast will
maintain light to moderate northwesterly winds across the coastal
waters. Strongest winds will remain over the northern outer waters
and north of the Bay Bridge. A mixed swell will continue across
the coastal waters.

&&

Mtr watches/warnings/advisories...
... Bay

&&

$$

Public forecast: Bell/Sims
aviation: drp
marine: drp



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