Santa Ysabel, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

146
FXUS66 KSGX 070357
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
857 PM PDT Sun Oct 6 2024

.UPDATE...

.SYNOPSIS...
Upper ridge begins to shift east, but hot conditions remain for
inland areas will continue through Monday with a subtle cooling
trend for mid week but still much above averages for inland areas.
A weak upper trough slides down the West Coast on Tuesday
replacing the heat dome. A more significant Pacific system
approaches California Friday into next weekend but the track of
this system is uncertain.

&&

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

Top of the marine layer is near 1300 feet MSL. This quickly moved
inland this evening along the coast after limited clearing at
beaches. Dense fog likely an issue Monday early morning. Dry air
above this layer with precipitable water under 0.60 inches but
enough for flat cumulus in the mountains again. Strong marine
inversions due to the upper ridge over Socal and coastal waters in
the lower 60s. We had 8 locations with record highs today as 27
to 29C 850 mb air mass was in place. The upper ridge will shift
east on Monday with only about 1C cooling of air mass and then a
weak elongated upper trough will arrive for Tuesday for additional
1 to 2C and tighter coastal gradient. Highs in the deserts are
still 15F above average on Tuesday, near 110F. This weak upper
wave closes off over Baja.

The air mass holds at 25C at 850 mb for inland areas and tight
gradient along the coast and marine layer should deepen some for
Tuesday and Wednesday. However, inland valleys, mountains still
have 5 to 10 degree above average daytime high temperatures and as
much as 10 to 15 degrees for the deserts.

There is a considerable range of solutions in the longer range
period for Friday to Sunday from an upper trough moving into
central and southern California to a system across the Great
Basin as an inside slider with period of offshore flow.

&&

.AVIATION...
070300Z...Coasts/Valleys...Low stratus has started to make its
way inland again this evening, bases at 200-600 ft MSL with tops
to 1000 ft MSL. Similar to last night, these will move 5-10 miles
inland overnight. Dense fog with VIS down to 1SM or less possible
for the coastal terrain, beaches, and valley areas through late
Monday morning. Clouds will clear to the immediate coast 16-18Z,
but low clouds and areas of fog will continue to stick to most of
the beaches, with only intermittent, partial clearing in the late
afternoon. Low clouds around 300-700 ft MSL will then move back
into coastal sites 01-04Z Tue.

Mountains/Deserts...FEW-SCT cu with bases 12-15k ft MSL may develop
once again late Monday morning through the afternoon in the vicinity
of the mountains. Otherwise, mostly clear skies with unrestricted
VIS expected through Monday morning.

&&

.MARINE...Fog with visibility 1-3 nm along the nearshore waters
tonight into late Monday morning. A Marine Weather Statement is in
effect for dense fog. Otherwise, no hazardous marine conditions are
expected through Thursday.

&&

.BEACHES...Fog and low clouds will continue to impact the beaches in
San Diego and Orange counties through this afternoon and into Monday
morning. Areas of dense fog with visibility below 1 mile possible.

&&

.FIRE WEATHER...
Had small wildfires today. Dry air remains in place with record
hot for the mountains and deserts so fire weather conditions
remain a concern with stress fuels from the past week of extreme
heat for October. Current trend the fuel moisture would be record
low in a few days. Energy release nearing highs as well.

&&

.CLIMATE...
Broke 8 records on Sunday at climate locations. Most notably is
latest in fall for 116 at Indio and 115 at Palm Springs. This is
the hottest start to the month of October, by several degrees at
Palm Springs with an average of 96.5F.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning until 8 PM PDT Monday for Coachella
Valley-San Bernardino and Riverside County Valleys-The Inland
Empire-San Diego County Deserts-San Diego County Valleys-San
Gorgonio Pass Near Banning-Santa Ana Mountains and Foothills.

     Heat Advisory until 8 PM PDT Monday for Riverside County
     Mountains-San Bernardino County Mountains-San Diego County
     Mountains.

PZ...None.

&&

$$

PUBLIC/FIRE WEATHER...Tardy
AVIATION/MARINE...CSP