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Area Forecast Discussion (AFD)

Issued by San Diego, CA (SGX)

FXUS66 KSGX 162051

Area Forecast Discussion
National Weather Service San Diego CA
151 PM 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 Tuesday.



At 1 PM, water vapor satellite imagery displayed an upper-level 
ridge centered around the AZ/NM/Mexico border, and an upper-level 
trough moving into central CA. A coastal eddy was helping to keep
stratus along portions of the coast this afternoon.

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 Tuesday
afternoon. Night/morning low clouds will be more restricted to 
coastal areas through the period.


161940Z...Coast/Valleys...Localized areas of low clouds with bases 
around 1000 ft MSL along the immediate coast. CIGS becoming more 
widespread after 04Z with bases 700-1100 ft MSL and widespread VIS 2-
4SM in BR on coastal mesas and elevated terrain. Low clouds expected 
to reach 15-20 miles inland tonight with bases around 1000 ft MSL. 
SCT conditions expected in the valleys 16-17Z and along the coast 17-
18Z Wed. 

Mountains/Deserts...Mostly clear skies expected through Wed. 


No hazardous marine weather is expected through Sunday.


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