Scientific Forecaster Discussion
fxus66 kmtr 271517
Area forecast discussion
National Weather Service San Francisco Bay area
817 am PDT Tue Jun 27 2017
Synopsis...seasonably cool temperatures can be expected today
with a very gradual warming trend through Friday as a ridge
builds into our region. Outside of drizzle, dry weather the next
7 days with night and morning coastal clouds followed by sunny
afternoons is forecast.
Discussion...as of 08:17 am PDT Tuesday...another morning of
June gloom for many as overcast skies blanket much of the area
thanks to the deep marine layer. Experimental and non-operational
GOES-16 shows the clouds spreading far into the Salinas valley and
into San Luis Obispo County at sunrise. Do expect the clouds to
clear by mid/late morning for most locations. Morning temperatures
are running about 2 to 5 degrees cooler than they were at this
time Monday and expect the trend to translate over to the
afternoon hours as well. Made minor changes to the sky cover grids
based on current trends; otherwise the current forecast is on
track. Please refer to previous discussion for additional details.
Previous discussion...as of 3:00 am PDT Tuesday...for those who enjoyed
yesterday, today will be very similar. Satellite imagery shows
widespread clouds over the waters with patchy clouds inland. Would
expect the extent of clouds to increase over the next few hours
along with possible drizzle and fog. Synoptically a deep marine
layer combined with a weak onshore flow and zonal flow aloft will
lead to another day of 60s to lower 70s at the coast with 70s to
the mid 80s inland. Westerly to northwesterly sea breezes will
kick in during the afternoon and evening with local gusts over 20
mph likely. Higher speeds can be expected over ridgetops plus
down the Salinas valley. Another round of patchy fog and drizzle
are forecast for tonight.
Starting on Wednesday temperatures will slowly warm through the
remainder of the work week as a ridge of high pressure rebuilds
toward our region. The warming will fall well short of last week
with inland highs will peak in the 80s to lower 90s instead of
the mid 90s to 105 that were hit last week. Coastal areas will
only see minor warming -- 60s and 70s.
Longer range guidance for next week favors temperatures near to a
bit above normal with continued dry conditions.
Aviation...as of 04:24 am PDT Tuesday...non-uniform marine layer
did re-develop overnight, but is patchy is some locations. All
terminals at least have some cigs from MVFR to IFR. Based on
guidance and burn off from yesterday will aim for mid morning
17-18z. VFR this afternoon. Cigs return tonight.
Vicinity of ksfo...IFR cigs through about 18z. Westerly winds
increasing to 20 kt this afternoon. Will have to monitor a
potential hole in the stratus deck north of the Airport.
Sfo bridge approach...similar to ksfo.
Monterey Bay terminals...IFR cigs through 17-18z. Gusty west winds
12-14kt this afternoon.
Marine...as of 04:22 am PDT Tuesday...moderate to locally strong
northerly winds will continue over the waters as high pressure
remains over the eastern Pacific. Winds will increase over all
waters on Wednesday. A dominant southerly swell will persist into
... Bay from 12 PM
Small Craft Advisory...Pigeon pt to pt pinos 0-10 nm from 12 PM
Small Craft Advisory...pt Arena to pt Reyes 0-10 nm from 3 PM
Small Craft Advisory...pt Arena to Pigeon pt 10-60 nm from 3 PM
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm
Small Craft Advisory...sf Bay from 1 PM
Public forecast: Rowe/Bell
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