Area Forecast Discussion
Issued by NWS San Diego, CA

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700
FXUS66 KSGX 240529
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
929 PM PST Thu Jan 23 2020

.SYNOPSIS...
High pressure over the West Coast will continue to build in
through Saturday, bringing dry weather and continued above normal
temperatures. A weak low pressure system will bring cooling on
Sunday to the region. High pressure will build back in on Monday,
bringing dry weather and a warming trend for next week.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

...Update...

Sunshine prevailed today with highs in the 70s commonplace, except
cooler in the mountains as well as in the high desert. Highs
across our service area ranged from 50F degrees at Mount Laguna
and Baldwin Lake to 80F degrees at Palm Springs (close to the
nation`s high, which was 82F degrees at Harlingen and McAllen,
Texas).

Patchy low clouds have formed near the coast. While we don`t
expect widespread low cloud coverage, patchy cloudiness will
continue near the coast overnight with a mostly clear sky inland.
No changes were needed to the forecast this evening.

...Previous Discussion (Issued at 145 PM PST Thu Jan 23 2020)...

At 1 PM, weak offshore flow was producing wind gusts of 20 to 30
mph in the mountains and foothills. Winds will continue to
diminish throughout the afternoon. Weakening offshore flow may
allow some patchy low clouds and fog to form along the immediate
coast overnight. Any low clouds and fog that forms will likely be
confined to the immediate coast and not push too far onshore
overnight.

High pressure near the West Coast will continue to build into
southern California through Saturday, resulting in dry weather
and warmer temperatures. Daytime highs will run a couple of
degrees warmer than normal along the coast, while in the valleys
and mountains, highs will be 5 to 10 degrees above normal. Warmer
weather will continue through Saturday, with little day to day
temperature variation.

High resolution models are showing a coastal eddy developing
Friday night and continuing through the weekend. This could bring
cooling near the coast Saturday and the return of low clouds at
times.

On Sunday, a weak Pacific trough will move inland and bring
cooling to the region. Deterministic models and their ensemble
solutions continue to trend weaker with this system, so
precipitation chances are decreasing. Little if any precipitation
is expected, but if any sprinkles do fall, it will be during the
day on Sunday. Nevertheless, stronger westerly winds can be
expected with gusts of 25 to 35 mph in the mountains and deserts
on Sunday.

High pressure over the eastern Pacific will build into the region
on Monday and strengthen throughout the week. This will result in
dry weather, a warming trend, and a shallower marine layer
through the end of next week.

&&

.AVIATION...
240500Z...Coast...Patchy stratus/fog will occur overnight within 5-
10 miles of the San Diego County coast but could drift out to sea
after 09Z Fri. Confidence is low with a BKN cig at any individual
airport, but if cigs occur they will likely be 800 feet MSL or
lower. Areas of vis 2-4 miles will occur overnight, with local vis
below 1 mile possible over higher coastal terrain. Low stratus/fog
will likely develop Fri evening.

Valleys/Mountains/Deserts...Mostly clear with unrestricted vis will
prevail through Fri evening.

&&

.MARINE...
A long-period WNW swell at 15-18 seconds/285 degrees will bring seas
of 7-10 feet in the outer coastal waters this weekend. Otherwise, no
hazardous marine conditions are expected through Tuesday.

&&

.Beaches...
A long-period WNW swell at 15-18 seconds/285 degrees will bring high
surf this weekend. Surf will be 6-8 feet in southern San Diego
County and northern Orange County, with generally 4-6 feet in
northern SD/southern Orange Counties. Strong rip currents are
expected through the period as well. High surf advisory is in effect
late Friday night through Sunday. Surf will lower late Sunday and
Monday, but another increase in surf is possible around next Tuesday.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory from 10 PM Friday to 6 PM PST Sunday for
     Orange County Coastal Areas-San Diego County Coastal Areas.

PZ...NONE.
&&

$$

PUBLIC...Gregoria (Update)/Connolly/JJT (Prev Discussion)
AVIATION/MARINE...Maxwell



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