Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
918 am PDT Wednesday Jul 23 2014
Synopsis...a gradual warming trend is expected to begin on
Thursday and continue into the upcoming weekend as high pressure
builds over the region.
Discussion...as of 09:09 am PDT Wednesday...given the clear start
to the day across the central coast...have nudged up afternoon
maximum temperatures across the region. Meanwhile...the Bay area
remains under cloud cover ahead of an approaching frontal
boundary. However...do expect these areas to see the cloud cover
burn-off later this morning or early afternoon. Overall...today
will be a transition day with the middle/upper level trough pushing
into the Pacific northwest and the strong ridge near the four
corner region beginning to build westward. More notable warming
trend will begin tomorrow and persist through the upcoming
Previous discussion...as of 3:00 am PDT Wednesday...after an active
day yesterday, a much quieter start to the day today. Satellite
currently shows a couple of small bands of high clouds drifting
across while closer to the surface the satellite and observation show a
mix of clouds and clear skies. Main stratus deck is well off the
northern coast right now and should be limited to the northern
third of our County Warning Area today. That will allow areas to the south to
quickly warm today as the Main Ridge of high pressure to the east
starts to build back into our County Warning Area. Highs will be in the 60s and
70s at the coast with middle 70s to upper 80s for most inland spots.
Temperatures will continue to warm through the rest of the week as the
ridge continues to expand into California while 850 mb temperatures
increase from 14-16c to 21-24c over the weekend. Sea breeze will
be very limited as a ridge at the surface attempts to build to
the north. Highs will increase to the upper 60s to lower 80s at
the coast with 80s and 90s inland. Far interior spots could top
100. In other words, look for a typical period of warm late July
weather. Models are also hinting at the return of some
subtropical moisture over the weekend from the south -- modified
total totals off the GFS are over 30 in parts of Monterey County
on Sunday. Will hold off any mention of showers or thunder until
newer runs of the NAM come in that go through the entire weekend.
Longer range guidance through next week keeps warmer than normal
weather through our area. Showers at this time look unlikely as
the ridge settles over the SW Continental U.S. And effectively blocks any
moisture from the south moving into our area. Confidence is high
through next week (cpc 6-10 day forecast gets a 5 out of 5 for
confidence placing it well above normal).
Finally, Worth noting that the Monterey Bay buoy set a record for
a water temperature of 67 degrees on Tuesday.
Aviation...as of 5:05 am PDT Wednesday...patchy low clouds
expected to linger over Bay area terminals till 18z this morning.
Mainly clear skies expected thereafter. Light westerly winds will
strengthen to around 15 knots with localized gusts to 25 knots this
afternoon. Moderate to high confidence.
Vicinity of ksfo...MVFR to VFR ceilings expected this morning over
area terminals. Clear skies are expected this afternoon and
evening. Light westerly winds will give way to moderate and
locally gusty winds this afternoon.
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR conditions expected through the
forecast period. Light and variable winds will strengthen to 10 to
15 knots with gusts around 20 knots this afternoon.
Marine...as of 09:09 am PDT Wednesday...high pressure building
over the eastern Pacific coupled with a thermal trough developing
over the California interior will result in increasing winds
across the coastal waters beginning this afternoon and evening.
The strengthening winds will result in deteriorating sea
... 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 from 6 PM
Small Craft Advisory...pt Reyes to Pigeon pt 10-60 nm from 6 PM
Small Craft Advisory...Pigeon pt to pt pinos 10-60 nm from 6 PM
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm from noon
Small Craft Advisory...pt Arena to pt Reyes 0-10 nm from 3 PM
Small Craft Advisory...pt pinos to pt Piedras Blancas 10-60 nm from 3 PM
Small Craft Advisory...pt Reyes to Pigeon pt 0-10 nm from 6 PM
Small Craft Advisory...sf Bay north of the Bay Bridge from noon
Public forecast: rgass
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