Area Forecast Discussion
Issued by NWS San Diego, CA

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FXUS66 KSGX 171558

Area Forecast Discussion
National Weather Service San Diego CA
858 AM PDT Mon Jun 17 2019

Weak low pressure will maintain cool weather in a deep marine layer
today with limited clearing. A ridge will nudge the low south on
Tuesday and Wednesday. This will bring some warming inland and lower
the marine layer for better inland clearing. Another, larger and
deeper trough will develop over the West Friday into Saturday. This
will bring stronger westerly winds to the mountains and deserts,
deepen the marine layer with more drizzle possible, and spread
cooling well inland through the weekend.



June should live up to it`s reputation today with abundant cloud
cover west of the mountains, and even some mist and drizzle. As of 8
AM PDT...numerous sites from inland O.C. to Otay Mesa in southern
San Diego County have measured from 0.01 to 0.10 inch. A
Precipitation Summary has been issued and posted to our web site.
Farther to the north and east, skies were mostly clear over the
deserts, although satellite imagery showed a patch of cirrus clouds
dropping south across SW San Bernardino County.

The 12Z Miramar sounding was completely saturated from the sfc to
2900 FT AGL. The 8C inversion base was near 3150 FT MSL. With the
low pressure center expected to drop over the Bight today,
expectations for clearing over coastal areas are muted. Even some
western valleys may be limited. A minor forecast update was issued
earlier. No additional forecast changes at this time.

A weak upper low will drop farther to the south on Tuesday, with a
weak ridge building in from the NW. This lowers the marine layer and
makes clearing inland more likely, but some coastal areas may still
have trouble. Consequently, it will remain cool in these areas,
while farther inland and across the deserts, temps rise to average
levels for mid June.

From previous discussion...

.LONG TERM (Thursday through Sunday)...
High pressure aloft will weaken on Thursday as a trough of low
pressure develops over the western states. This will bring
stronger onshore flow for Friday into Saturday with stronger and
gusty southwest to west winds in the mountains deserts. The marine
layer will deepen with more limited clearing towards the coast and
some night and morning drizzle for coastal and some valley areas.
This will also spread cooling inland for Friday and Saturday. On
Sunday, the trough of low pressure and onshore flow will begin to
weaken. There will be some warming for inland areas with the
marine layer not quite as deep.


171550Z...Coast/Valleys...OVC010-020 through 18Z with lcl CIGS 005-
010 and areas of vis of 2-4 SM BR. Skies clearing back to the
coastal zone through 23Z, but cigs will likely persist at coastal
TAFs (KSAN, KSNA, KCRQ) through the day. Low clouds with similar
bases moving back inland and into the valleys after 18/02Z with
areas of local vis 3-5 SM in BR.

Mountains/Deserts...Mostly clear with unrestricted vis today. West
winds with sfc gusts 25-35 kt along mtn crests, desert mtn slopes,
and below passes, with progressive weakening overnight. Areas of MOD
UDDFTS over and east of the mtns.


No hazardous marine conditions through Friday.


Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.





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