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Area Forecast Discussion (AFD)

Issued by San Diego, CA (SGX)

FXUS66 KSGX 161613

Area Forecast Discussion
National Weather Service San Diego CA
913 AM PDT Tue Jul 16 2019

Upper-level low pressure moving into the region will create a
deeper marine layer and cooler weather across the area through
Saturday. High pressure building to the east early next week will
create near normal high temperatures by Tuesday. A gradual influx
of monsoonal moisture will create a slight chance of afternoon 
thunderstorms near the mountains on Monday and Tuesday.



At 8 AM, water vapor satellite imagery displayed an upper-level
ridge centered around the AZ/NM/Mexico border, and an upper-level
trough moving into northern CA. Dense fog was observed along the
coast this morning, but visibility is slowly improving. A few
areas will have visibility of 1/2 mile or less over the next hour
while the marine layer stratus clears towards the coast. The Dense
Fog Advisory was allowed to expire at 8 AM. 

Ensembles are in good agreement with the trough moving across CA
through Wednesday, and southwest flow aloft lingering over the
region through Saturday. This will create a deeper marine layer,
developing night/morning low clouds and fog further inland into
the valleys and cooler weather across the region. Highs today will
be between 5 degrees below normal to 5 degrees above normal, then
most areas will be just below normal Wednesday, then highs will be
from 5 to 15 degrees below normal Thursday through Saturday.

Ensemble solutions become a bit scattered for the overall pattern
early next week, however confidence is moderate to high that a
ridge will strengthen over the Four Corners region. This will help
increase our high temperatures to mostly near normal by Tuesday.
Monsoonal moisture will start to move into the region, with
a slight chance of thunderstorms possible over the mountains 
Monday and Tuesday afternoons. Night/morning low clouds will be
more restricted to coastal areas through the period.


161500Z...Coast...BKN-OVC002-006 and VIS 1/4-3SM in BR/FG through 
16Z. Mostly clear skies expected after 16Z. CIGS redeveloping after 
05Z Wed with higher bases 700-1100 FT MSL and widespread VIS 2-4SM 
in BR on coastal mesas and elevated terrain. 

Valleys/Mountains/Deserts...Brief CIGS may intrude into westernmost 
portions of the valleys Tuesday night but coverage is not expected 
to be widespread. Otherwise, CLR with unrestricted vis. 


Dense fog with less than 1 mile visibility expected over the coastal 
waters until late morning. Otherwise, no hazardous marine weather 
is expected through Saturday.


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