Area Forecast Discussion
Issued by NWS San Diego, CA

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FXUS66 KSGX 170528

Area Forecast Discussion
National Weather Service San Diego CA
930 PM PST Fri Nov 16 2018

Fair weather will prevail through next Tuesday with occasional high
clouds as well as patchy night and morning coastal low clouds and
fog. A low pressure trough will prevail along the west coast the
second half of next week and bring small chances of rain along with
cooler days.



Areas of high clouds were drifting over at mid-evening, and a few
patches of stratus were forming just inland from the coast. Aircraft
soundings showed a weak marine inversion base around 800-1000 feet
above sea level, which is high enough to preclude fog at lower
coastal elevations, but some fog could form in the 600-1000 foot
elevation range overnight, though the weak inversion should keep
stratus rather patchy.

A high pressure ridge will continue over the west coast through
Monday, with generally west flow aloft and at the surface over
SoCal. Moderate to occasionally thick high clouds should continue to
drift over through at least Saturday night. HRRR smoke model shows
the bulk of the heavy smoke staying off the San Diego/Orange County
coasts, but some smoke, both at the surface and aloft will
occasionally move in through Saturday, mainly near the coast. The
marine layer depth will stay the same or even lower slightly through
Monday due to slight height rises and minimal coastal eddy activity,
so any low clouds/fog that form will stay near the coast.
Temperatures will generally be a little above seasonal averages
through Monday.

Around Tuesday, we start to get more troughing off the coast, with
models showing a fairly vigorous short wave moving through the
region, but with insufficient moisture for precipitation. A long
wave trough will develop over the west coast by midweek, and this
will bring at least small chances of rain the second half of next
week. ECMWF has been more aggressive with moisture/precipitation
than the GFS, but with energy and moisture focused farther north
than SoCal, we will most likely have lighter precipitation. There
should be cooling the second half of next week, though nothing
drastic as temps will probably be just slightly below normal.


170420Z...Coastal Areas...Patchy low clouds, with bases 700-1000 ft
MSL and tops near 1500 ft MSL, will develop late tonight along the
coast and could spread locally a few miles inland by 14Z Sat. VIS of
2-4 miles in fog could occur with clouds near higher terrain.
Impacts at coastal TAF locations are possible between 10Z and 14Z
Sat, but not probable. Clearing to the coast is likely by 17Z.

Elsewhere SCT-BKN at or abv 15000 ft MSL with unrestricted vis
through Saturday.


No hazardous marine weather is expected through Tuesday.


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




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