Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
1032 am PDT Thursday Jul 24 2014
Synopsis...mostly clear with a warming trend today through
Saturday with weak offshore flow in the hills. Continued warm and
dry inland over the weekend through early next week while mild
weather persists at the coast with a return of coastal low clouds
Discussion...as of 08:55 am PDT Thursday...patchy coastal clouds
developed along the coast this morning and pushed locally inland
across the East Bay and down into the Monterey/Salinas areas.
Expecting the cloud cover to burn-off rapidly this morning giving
way to mostly sunny skies across all of the region. Temperatures
this afternoon will be a few to several degrees warmer than
Wednesday as 850mb temperatures warm as a result of building high
pressure. Have made a few updates to reflect current temperature
trends and cloud cover based on visible satellite.
Will be taking a closer took at temperatures for tomorrow
afternoon. Very warm to hot conditions looking more likely for the
San Francisco Bay area. Look for more details on tomorrow's heat
in the afternoon forecast package.
Previous discussion...as of 3:05 am PDT Thursday...a fairly strong
middle-Summer trough is currently moving onshore in the Pacific
northwest. This is causing a strong northerly gradient to develop
along the northern California coast with sfo-acv currently 6 mb.
This has swept most of the low clouds from the ocean although a
shallow cloud deck has bumped up along the coastline with Half
Moon Bay currently reporting a 600 foot cloud deck and 1100 feet
at ksfo. Any low clouds and fog are forecast to quickly mix out
after sunrise this morning as drier air filter over the region.
Main weather story the next few days will then be significant
warming...especially for inland areas and those that are favored
by light north/northeast winds in the hills...such as the North
On Wednesday highs in the North Bay were only in the low 80s and are
forecast to warm from the upper 80s to upper 90s from this
afternoon through Saturday as the thermal trough will shift
towards the coast each morning with light offshore breezes in the
hills and only a weak afternoon sea-breeze. Places like the East
Bay valleys will likely see temperatures warm above 100 degrees by
Friday afternoon. Friday looks like the hottest day at this time
but any cooling on Saturday looks to be subtle...on the order of
only a few degrees.
The long range forecast will feature seasonable weather. A weak
upper low well off the coast will keep onshore winds in place and
with SST cooling back to normal under northwest winds expect to see
more widespread coastal low clouds and fog by early next week
while inland areas will remain warm to hot as The Four Corners
high expands westward over California with its influence being
felt over the Central Valley and eastern sections of the greater
Aviation...as of 10:32 am PDT Thursday...a thermal trough
positioned over interior California is resulting in moderate winds
over the coastal waters today and light offshore winds over the
terminals. This is resulting in clear skies across the forecast
area with the exception of cloudy skies in Monterey...which should
clear out shortly. Light offshore winds in the lower atmosphere
should maintain VFR in the sf Bay area overnight with stratus
expected to return for a brief period overnight in Monterey and
Vicinity of ksfo...VFR conditions are expected through the next 24
to 36 hours. The sea breeze is expected to reach 15 to 20 knots this
afternoon with gusts to 25 knots.
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR is anticipated today with IFR
ceilings returning to the terminals around midnight. The sea breeze is
expected to reach 8 to 12 knots this afternoon.
Marine...as of 10:35 am PDT Thursday...sea conditions will
deteriorate today as northwesterly winds increase across the
coastal waters. Winds are anticipated to decrease along the inner
and southern coastal waters Friday into the weekend as the surface
pressure gradient weakens.
... Bay from 3 PM
Small Craft Advisory...Pigeon pt to pt pinos 0-10 nm from 3 PM
Small Craft Advisory...pt Arena to pt Reyes 10-60 nm
Small Craft Advisory...pt Reyes to Pigeon pt 10-60 nm
Small Craft Advisory...pt Arena to pt Reyes 0-10 nm
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm
Small Craft Advisory...Pigeon pt to pt pinos 10-60 nm
Small Craft Advisory...pt pinos to pt Piedras Blancas 10-60 nm
Small Craft Advisory...sf Bay north of the Bay Bridge from 2 PM
Small Craft Advisory...sf Bay south of the Bay Bridge from 2 PM
Public forecast: rgass
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