Crestline, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

987
FXUS66 KSGX 121946
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
1246 PM PDT Sun Jul 12 2026

.SYNOPSIS...
Near normal temperatures expected through Monday, with hotter and
humid weather moving into the middle of the week. Thunderstorm
chances from the monsoon are in the forecast over the mountains
and locally into the deserts each afternoon through much of the
week. Coastal flooding will impact beaches through Tuesday with
evening high tides exceeding 7 feet.

&&

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

A decaying storm system that occurred to our south and east last
night is moving through the area today, providing clouds and some
reports of sprinkles. This cloud cover will limit some afternoon
heating today, though the humidity will be more apparent starting
today through the upcoming week. These clouds will also further
inhibit storm development over the mountains; cumulus may form
with some areas of weak thunderstorms but chances remain near
15-25%.

A strong area of high pressure currently over the Northern
Rockies will continue to expand into the Northern Plains.
Clockwise flow around this system, with the help of a weak trough
offshore, will aid to bring in better moisture from the monsoonal
wind pattern to our area by Monday. The mountains and deserts
have the greatest chances (35-55% chance) to see bouts of heavy
rainfall, lightning, and small hail Monday afternoon and evening.
Hi-res models show the mountains from the Mexican border up north
to Big Bear and into the high desert as the notable places that
may see storm activity. Confidence is low to moderate on how far
west this moisture and instability will move during this time
period with limited chances west of the mountains. Monday`s highs
will be similar to that of today, as cloud cover from storms in
Arizona moving toward our area, which may limit high temperature
readings yet again.

A subtle decrease in moisture is seen in the latest model
guidance for Tuesday through Thursday as high pressure slowly
expands over the region. This will decrease chances for storms in
the mountains, but increase high and low temperatures. An Extreme
Heat Watch is now in effect for all areas from the coast to below
6,000 feet in the mountains during this time period. There is
high confidence that the peak of the heat will be on Wednesday,
though confidence is lower on exactly how hot temperatures will
be. Highs well into the 90s for the mountains and coastal valleys,
triple digits for the Inland Empire and potentially the eastern
San Diego Co valleys are in the cards. Low temperatures will also
be in the 70s across much of this region. This, along with
increased humidity, will give areas moderate (rating 3/5) to major
(4/5) Heat Risk. Vulnerable populations and those who are outside
for long periods will have a greater chance to see heat impacts
and related illnesses. Limited places will be available to cool
off, including the mountains, so please limit time outdoors if you
are able to do so.

The center of the high looks to retrograde and become more
amplified toward somewhere near the Colorado Rockies, which would
provide a greater influx of moisture by the end of the week. NBM
has increased chances for thunderstorms returning to inland areas
by Thursday into the end of the week, as temperatures return
closer to normal. Confidence remains low on where exactly any rain
could fall, especially for deserts and the valleys west of the
mountains.

&&

.AVIATION...
121800Z....Coast/Valleys...Patchy low clouds have completely moved
out with ongoing BKN-OVC high clouds AOA 15kft MSL through Monday.
Low clouds will develop again this evening, but will be extremely
patch with only moderate confidence (45-70%) of a CIG at
KSAN/KCRQ/KSNA overnight. If clouds manage to make it in, bases will
be around 1200-1800ft MSL with impacts likely not occurring until
after 06-08z Mon (potentially as late as 13z Mon for KSNA). Any
inland low clouds will clear out by 16-17z. Otherwise, the high
clouds will prevail.

.Mountains/Deserts...SCT-OVC mid/high clouds AOA 15kft MSL
through Monday and generally unrestricted visibility. There is a
slight chance (10-l5%) of thunderstorms over the mountains this
afternoon, with any storm capable of gusty and erratic winds and low
visibility due to heavy rain.

&&

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

&&

.BEACHES...
Astronomical high tides peaking 7.0-7.5 ft each day today through
Tuesday. High tides combine with a modest south swell (3 ft swell at
13-15 seconds from 190 degrees) to generate surf of 3-5 ft for south-
facing beaches and 2-4 ft elsewhere. This will produce areas of
coastal flooding in low lying areas, boardwalks, beach parking lots,
and beach adjacent streets during evening high tides. Highest tides
each evening will generally occur between 8 and 10 PM. A Beach
Hazards Statement is in effect for Sunday afternoon through Tuesday
evening and contains the details. There will be an increased risk of
rip currents through Wednesday.

&&

.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 Tuesday evening for Orange
     County Coastal Areas-San Diego County Coastal Areas.

PZ...None.

&&

$$

PUBLIC...APR
AVIATION/MARINE...Zuber