119
FXUS66 KSGX 191515
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
815 AM PDT Sun May 19 2024

.SYNOPSIS...
A large-scale trough over western North America will persist
through this week. Temperatures will remain below seasonal
averages with gusty winds across the mountains and deserts. A
closed upper level low will move across the region on Monday,
which will bring the coolest and windiest conditions overall. Low
clouds will continue nights and mornings, retreating back to the
coast each afternoon.

&&

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

This morning, the sounding and aircraft reports show the marine
layer about 3000 ft deep with low clouds beginning to clear
inland. The inversion strength is similar to yesterday and so is
the pattern of clearing, with San Diego County clearing faster
than the Inland Empire and Orange County. Sfc pressure gradients
are currently onshore at 6.4 mb SAN-TPH and 7.0 mb SAN-IPL. This
continues to support sw to west winds gusting 35-50 mph in the
favored mtn passes and canyons.

A closed upper low currently about 900 miles southwest of San Diego
will be drawn into the mean flow and become an open wave over SoCal
on Monday as a large-scale trough to the north deepens. This will
bring additional cooling to the region and Monday will likely be
the coolest day of the week. Temperatures will be near 5 degrees
below average across the coastal areas with up to 10 degrees below
average for inland areas. It will also strengthen the westerly
winds, especially in the mtns and adjacent desert areas where
chances are good for wind gusts over 40 mph and over 55 mph in
wind-prone mountain passes. The San Gorgonio Pass will have a
70-80% chance of wind gusts exceeding 55 mph

The trough over the West Coast will continue, though not as
amplified as Monday. Rising heights will lead to some warmer
conditions and somewhat weaker winds over inland regions. Little
day-to-day variations in temperatures, winds and marine layer
clouds can be expected from Tuesday through the end of the week,
where we will see slightly below average temperatures and May Gray
conditions west of the mountains in the morning with general
clearing toward the coast by the afternoons. As we get into next
weekend, the consensus of model solutions shows the dominant
trough weakening and a building ridge of high pressure centered
over eastern Mexico. At this time, it seems likely that the
weather over SoCal will continue to be dominated by troughing over
western North America.

&&

.AVIATION...
191530Z...Coast/Valleys...Low clouds covered the area west of the
mountains and are beginning to clear at the inland edges at this
hour. Bases are 2000-2500 ft MSL with tops to 3200 ft MSL,
obscuring higher terrain. Expect clearing 16Z-19Z in the valleys
and 18Z-21Z near the coast, with SCT-BKN conditions lingering at
the beaches into the afternoon. Low clouds will spread rapidly
inland after 01Z Monday, reaching the inland valleys by 09Z.
Bases 1500-2000 ft and tops around 3000-3500 ft MSL by Monday
morning.

Mountains/Deserts... Mostly clear with unrestricted vis through
Monday morning. Areas of W-SW winds gusting 30-45 kt from the
mountain crests east through the desert slopes and into the
deserts will continue at times through tonight, accompanied by MOD
UDDFS and LLWS over/E of the mtns.

&&

.MARINE...
No hazardous marine conditions are expected through Thursday.

&&

.BEACHES...
A series of southwest swells of 2-3 ft at 16-18 seconds from 200-220
degrees will build today and continue through Tuesday, producing
surf of 3-5 ft with locally higher sets on exposed southwest
facing beaches, as well as a high risk of rip currents at all
beaches. A Beach Hazards Statement has been issued for today
through Monday evening. Swell and surf will slowly lower Wednesday
and Thursday.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Monday evening for Orange County
     Coastal Areas-San Diego County Coastal Areas.

PZ...None.

&&

$$

PUBLIC...PG
AVIATION/MARINE/BEACHES...PG