932
FXUS66 KSGX 060917
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
217 AM PDT Sat Jul 6 2024

.SYNOPSIS...
An area of high pressure will dominate the weather pattern over
the next week, leading to hot conditions inland. The high is
expected to weaken slightly by Monday, but restrengthen by Tuesday
and Wednesday bringing minimal relief. This weather system will
keep the marine layer quite steady, with moderated temperatures
near the coast and night/morning low clouds each day with morning
fog across elevated terrain. The ridge of high pressure will push
further east by later next week, allowing the potential for
monsoonal moisture to reach the mountains and deserts with
continued warm conditions across SoCal.

&&

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

After record breaking temperatures today, lower elevations along
and west of the mountains have cooled off nicely. The warmth
remains in some areas with a strong inversion in place, where some
higher terrain spots are in the 80s at this hour. The area of
high pressure over California responsible for this will continue
to impact the area today, though most areas will see temperatures
a couple degrees cooler. 850 mb temps will still be elevated but
slightly less overall. Low level moisture surges will impact lower
desert regions each morning, leading to very hot and muggy
conditions. Risk of heat impacts will be high to extreme yet again
today and Sunday from the foothills, into the mountains and over
the deserts. Long duration outdoor recreation is highly
discouraged, since temperatures will soar very quickly each
morning and stay quite warm overnight. Make sure to drink plenty
of fluids and check on those susceptible to the heat. Slight
cooling will be seen for valleys and southern mountain areas as
onshore flow increases on Sunday, though still near 5 to 10
degrees above normal. West winds will pick up near 20-35 MPH
(locally 45 MPH) for mountain passes into the deserts by Sunday
afternoon and evening.

By Monday, the high centered over Northern California will push
over Southern California, weakening slightly, though 850 mb temps
look to stay similar to Sunday. This may drop temperatures a
degree or two by Monday afternoon where most locations from the
coastal valleys to the mountains will be in the 80s to near 100
degrees. Ensemble forecast guidance shows the ridge of high
pressure amplifying over SoCal into the Great Basin by Tuesday and
Wednesday, where the air mass will warm once again. This will
bring temperatures back up to levels similar to this weekend,
though the deserts will remain hot with highs near 115 to 120 in
the lower deserts most days.

Confidence in the forecast remains moderate as we head into later
next week, mostly due to the placement of this large dome of high
pressure. Global ensembles are in fairly good agreement, depicting
the high pushing slightly eastward by Thursday through Saturday.
If this occurs, southerly flow around the high would pull in
moisture into our region, which may be able to give mountains and
deserts a shot at showers and thunderstorms. This monsoon signal
begins with minor chances by Thursday, increasing some by Friday
and Saturday per NBM. Chances remain near 10 percent at this time,
so keep an eye on the forecast as we get closer.

&&

.AVIATION...
060915Z...Coast...Low clouds will gradually cover coastal areas this
morning, with cloud bases 600-800 feet MSL and tops to 1500 feet.
Low clouds could extend locally 15-20 miles inland by 15Z. Vis
reductions 2-5SM in BR over higher coastal terrain. Scatter out
expected 15-17Z, but with areas of low clouds persisting along
beaches into this afternoon. Low clouds with similar bases will
gradually move ashore after 04Z Sunday.

Otherwise, mostly clear skies with unrestricted vis through today.

&&

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

&&

.BEACHES...
A long-period south swell will continue to create elevated surf. The
surf will peak today before subsiding on Sunday. Sets of 6-7 feet
can be expected on south and southwest-facing beaches, especially in
Orange County. Check the Beach Hazards Statement for details.

&&

.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 Sunday afternoon for Orange
     County Coastal Areas-San Diego County Coastal Areas.

     Excessive Heat Warning until 9 PM PDT Sunday for Riverside
     County Mountains-San Bernardino County Mountains-San
     Bernardino and Riverside County Valleys-The Inland Empire-
     San Diego County Mountains.

     Excessive Heat Warning until 9 PM PDT this evening for San Diego
     County Valleys.

     Heat Advisory until 9 PM PDT this evening for Orange County
     Inland Areas-Santa Ana Mountains and Foothills.

     Excessive Heat Warning until 9 PM PDT Wednesday for Apple and
     Lucerne Valleys-Coachella Valley-San Diego County Deserts-
     San Gorgonio Pass Near Banning.

PZ...None.

&&

$$

PUBLIC...APR
AVIATION/MARINE...PG