San Marcos, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

662
FXUS66 KSGX 221135
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
335 AM PST Sun Dec 22 2024

.SYNOPSIS...
Warm and dry weather will occur through Monday areas of fog each
morning across the coast and western valleys. A trough off the
coast will come ashore by Tuesday, bringing some cooler weather,
gusty winds, and a chance of showers. Drier weather will return
from Christmas Day into next weekend with a warming trend as high
pressure moves into the region.

&&

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

A large 960mb area of low pressure off the West Coast continues
to bring in higher level clouds across SoCal. This is acting to
inhibit the marine layer and low cloud/fog development with only a
few small patches mainly offshore and coastal San Diego County as
seen on GOES imagery. Whatever fog does form later this morning,
may be dense and quite intermittent across the coast and far
western valleys. The marine layer will deepen slightly overnight
tonight, allowing foggy conditions to spread further inland. We
will have to see if the high clouds stick around though, which
could inhibit cloud formation once more. The most likely scenario
is higher clouds moving through our area today, with better
clearing tonight.

Dry weather will continue through Monday as the trough moves into
Northern California. By Tuesday, model guidance continues to point
at a dip in the trough, allowing more active weather to move into
the region. Light shower chances will increase by early Tuesday
afternoon and overnight. Showers still look to be on the lighter
side with mainly near one tenth or less west of the mountains and
high desert, with close to one quarter of an inch in the mountains.
This weather system will also bring gusty west winds across
mountains and deserts. Confidence in wind speeds has increased
with latest guidance, so wind speeds are a bit higher with the
latest forecast. Most areas will see winds 25-45 MPH, locally over
50 MPH in favored passes by Tuesday night.

By Wednesday, we will dry out with more sunshine behind the
trough with cooler air. Christmas Day will be the coolest day of
the week overall with highs within a few degrees of normal. While
a series of waves bring more rain to NorCal next week, high
pressure to the southwest will slowly regain strength. This will
keep us dry by Christmas Day into next weekend with a subtle
warming trend with temperatures back above normal away from the
coastal areas.

&&

.AVIATION...
221100Z....Coasts/Valleys...A few stray areas of low clouds based
around 200-500ft MSL are lurking within 20 miles of the San Diego
County coast with another patch more recently building near KSAN.
While coverage of these clouds has increased some over the last few
hours, widespread CIGs or fog is not expected this morning. KSNA
looks to stay clear of any low clouds and KCRQ may see an occasional
CIG. KSAN holds the best chance for CIGs through the next several
hours, but they may be come and go at times. VIS reductions should
stay between 1 and 5 miles and locally below 1 mile over mainly
higher coastal terrain. Any clouds that snuck ashore should clear
out by 16-18z Sunday.

Low clouds look to rebuild this evening with greater coverage but
also higher bases, most likely 700-1200 ft MSL. CIGs expected to
fill in on the coasts around 03z, spreading 10-15 miles inland by
09z Monday. VIS restrictions likely limited to the higher terrain and
coastal mesas.

.Mountains/Deserts...SCT-BKN high clouds at/above 20000 ft MSL with
unrestricted VIS will prevail through early Monday morning.

&&

.MARINE...
Long period WNW swells (280-290 deg) of 8-11 feet continue to
increase this morning through Tuesday night, with the highest swells
in the outer coastal waters where a Small Craft Advisory is in
effect. 8-9 foot waves could occur within 30 NM of the coast but
with relatively long periods of 16-20 seconds. Wind gusts of 20-25
kt are expected Tuesday night in the outer coastal waters.

&&

.BEACHES...
Long period (16-20 second) west to northwest swells (280-290 deg)
arriving this morning will result in high surf of 6-12 feet with
locally higher sets through Wednesday. This will make swimming
hazardous and pose a minor coastal flooding threat. Elevated surf
will continue late in the week as additional, albeit somewhat
smaller swells occur. See the High Surf Advisory for more details.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory until 4 AM PST Wednesday for Orange County
     Coastal Areas-San Diego County Coastal Areas.

     Dense Fog Advisory until 9 AM PST this morning for San Diego
     County Coastal Areas.

PZ...Small Craft Advisory until 4 AM PST Wednesday for Waters from
     San Mateo Point to the Mexican Border Extending 30 to 60 nm
     out including San Clemente Island.


&&

$$

PUBLIC...APR
AVIATION/MARINE...Munyan