596
FXUS66 KSGX 302059
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
159 PM PDT Sun Jun 30 2024

.SYNOPSIS...
Dry and warm weather will continue through this week, with a long
duration heat wave impacting far inland regions by the middle and
end of the week. Desert regions will see triple digit heat with
highs near 10 to 15 degrees above normal. The marine layer will be
shallow, where areas near the beaches and adjacent valleys will
see night and morning low clouds most days.

&&

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

.SHORT TERM (Through Tuesday)...
Temperatures this afternoon are rising into the 80s and 90s for
most areas west of the mountains, with near 70 at the beaches as
clouds clear in OC and stick a bit more in SD Co. Clouds will
retreat back inland about 20 miles near to just after sunset this
evening with mostly clear skies elsewhere. W/SW winds are
beginning to pick up near 20-30 MPH across mountain passes, with
slight increase in winds expected by this evening.

A weak trough passing overhead will continue its trek eastward by
Monday. This will lead to little change in the weather pattern,
with highs a few degrees cooler than today west of the mountains.
Highs near 100 degrees are likely from the Inland Empire into the
high deserts, with highs in the upper 80s across the higher
elevations. A nearly 600 dm high pressure system over the Pacific
will move eastward and slightly expand by Tuesday, warming areas
away from the coast by a few degrees. This will begin a warming
trend into the end of the week, leading to a long-duration heat
wave for inland areas. Not only will hot temperatures occur
during the day but also at night.

&&

.LONG TERM (Wednesday into Next Weekend)...
Winds will weaken for mountains and deserts for the period, with
a shallow marine layer within 20 miles of the coast, leading to
patchy fog each morning. A large area of high pressure over the
Southern States along with an inverted trough off the coast of
northern Mexico will help feed elevated moisture into the region,
which will lead to a more humid day, especially for the deserts.
Confidence on any storm development is still very low at this
time, but we will continue to monitor.

The aforementioned area of high pressure will grow and expand
across the State from the middle to the end of the week. 850mb temps
peak across SoCal by Friday and Saturday. Hot temperatures are
likely for those away from the coast starting Wednesday into the
long holiday weekend. Triple digit heat is likely for much of the
week for those along and east of I-15 in the Inland Empire, and
certain for all desert regions. Highs near 110 degrees have a
40-70 percent chance of occurrence across the high desert, with
60-80 percent chance of highs 115 or greater for the lower deserts
by Friday and Saturday. High temperatures have a moderate to high
chance of reaching into the 90s from areas east of I-5 in OC to
east of I-15 in SD Co, highest chances on Friday and Saturday.

No matter how you slice it, it`s going to be a hot week and long
holiday weekend for areas away from the coast! Moderate to high
heat risk will lead to elevated impacts for those outdoors. Make
sure to take frequent breaks if working outside, drink plenty of
water, and be safe and smart while doing outdoor recreation. This
heat wave will bring hot temperatures well into the 80s and 90s
across the mountains!


&&

.AVIATION...
301940Z...Coast/Valleys...Mostly clear skies with unrestricted VIS
this afternoon. Low clouds returning to coastal areas after 05-06Z
Monday with less coverage, and bases similar to this morning or
perhaps slightly lower, around 500-900 FT MSL. Scatter out timing
looks similar to this morning, generally 15-17z Mon.

Inland...Westerly winds gusting locally 25-30 knots through Cajon
and San Gorgonio Passes and into adjacent deserts again this
afternoon/evening. Mostly clear skies with unrestricted VIS today
except SCT100, mainly over mountains.

&&

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

&&

.BEACHES...
A long-period swell of 2-3 feet from 190 degrees with a period of 16-
18 seconds will arrive at SoCal beaches as early as Wednesday
morning, peak Friday and gradually subside next Sunday. This may
lead to elevated surf with breaking wave heights of 6-7 feet, mainly
on exposed south and southwest-facing beaches in Orange County. Rip
current risks will also increase accordingly.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning from 11 AM Tuesday to 5 AM PDT Monday for
     Apple and Lucerne Valleys.

     Excessive Heat Warning until 8 PM PDT Friday for Coachella
     Valley-San Diego County Deserts-San Gorgonio Pass Near
     Banning.

PZ...None.

&&

$$

PUBLIC...APR
AVIATION/MARINE...Adams