Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

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FXUS66 KMTR 230021
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
521 PM PDT Mon Jul 22 2019

.SYNOPSIS...A gradual warming trend will continue through midweek,
especially across the interior. This will lead to seasonably warm
temperatures inland while coastal areas remain mild under the
influence of the marine layer as onshore flow persists.

&&

.DISCUSSION...as of 01:55 PM PDT Monday...Satellite imagery shows
low clouds along much of the coast with the marine layer situated
at around 1000-1200 ft AGL. Temperatures across the region this
afternoon are about 5 to 10 degrees warmer than this time
yesterday as high pressure builds over the Four Corners. Coastal
areas are currently in the upper 60s to low 70s while inland areas
are in the mid 80s to low 90s. Expect a few additional degrees of
warming this afternoon before temperatures begin to cool off for
the evening. The latest run of the 12z NAM remains consistent in
showing an increase in mid/upper level moisture over eastern and
southern California as well as increased mid/upper level
instability this afternoon/evening. Any resulting high based
convection that develops is still expected to remain outside of
our forecast area with only an increase in mid/upper level clouds
over the southeastern portion of the region. Stratus offshore will
move inland once again tonight with patchy fog along the coast
possible late tonight and into tomorrow morning.

This week`s warming trend will stall tomorrow as a mid/upper low
currently over the eastern Pacific shifts northeastward while its
associated trough moves into the Pacific Northwest. Warming will
then continue over the interior on Wednesday as high pressure over
the Four Corners strengthens and builds westward into California.
Inland locations will see more widespread 90s mid-week with
isolated locations reaching 100 degrees. Persistent onshore flow
will likely keep a shallow marine layer in place resulting in
continued night/morning low clouds and patchy fog along the coast.
This will also act to keep highs for coastal areas in the mid 60s
to mid 70s. High pressure to our east will continue to be the
main driver of our weather through the end of the week and into
the upcoming weekend. This will keep seasonably warm conditions
across the interior with temperatures at or just above seasonal
averages while coastal areas remain relatively mild thanks to the
influence of the marine layer.

&&

.AVIATION...as of 4:58 PM PDT Monday...A shallow 1200 ft marine
layer persist along the coast this afternoon with status covering
much of the coastlines. Anticipate a return of stratus overnight
to coastal terminals such as KMRY and KSNS. The shallow marine
layer will like keep low clouds out of inland terminals. Moderate
onshore flow will gradually ease after sunset becoming light and
locally variable overnight.

Vicinity of KSFO...VFR conditions will prevail through the
forecast period. Moderate onshore flow to around 20 kt expected
through this evening with winds gradually diminishing after sunset
becoming light around 5 to 10 kt overnight.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR conditions will prevail through early
evening with IFR cigs returning between 03z-05z tonight. Clearing
is anticipated around 17z Tuesday morning. Onshore flow around
8-12 kt will diminish becoming light and locally variable
overnight.

&&

.MARINE...as of 2:32 PM PDT Monday...Breezy northwest winds will
continue at times through Tuesday over the coastal waters. Winds
will increase over the waters and become gusty Tuesday night and
Wednesday as high pressure builds into the Pacific Northwest and
northern California. Light southerly swell coupled with short
period wind waves will continue through the week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tngt...SCA...SF Bay until 9 PM
             SCA...Pigeon Pt to Pt Pinos 0-10 nm until 9 PM
             SCA...Pt Arena to Pt Reyes 0-10 nm
             SCA...Pt Arena to Pigeon Pt 10-60 nm
             SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm from 3 AM
             SCA...Pt Reyes to Pigeon Pt 0-10 nm from 9 PM
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm from 9 PM

&&

$$

PUBLIC FORECAST: AS
AVIATION: CW
MARINE: ST

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