Alta Loma, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

259
FXUS66 KSGX 312042
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
142 PM PDT Sat May 31 2025

.SYNOPSIS...
An area of low pressure to the south will bring a chance for
showers and thunderstorms this weekend. Cooler weather with
temperatures near normal will occur by Sunday through much of the
upcoming week. After Sunday, dry weather will continue with quiet
conditions.

&&

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

Thunderstorms have made their way across southern areas of the
San Diego metro this afternoon as high clouds fill into the
region. After this pushes through, light showers with a lesser
chance of thunderstorms is expected across parts of San Diego
County through this evening. The low to the south will eventually
drift northward tonight, providing a chance for showers across
most of Southern California into the morning hours. Areas west of
the mountains will generally receive light precipitation under one
tenth of an inch, with parts of Orange County receiving none.
WRF/HRRR models depict heaviest thunderstorm cells across parts of
the Riverside and San Diego County mountains with rainfall rates
nearing one half inch per hour. This aligns fairly well with model
depictions of highest CAPE over this area near 300-600 J/kg. The
exact area that receives thunderstorms will depend on the low`s
track, where a low moving further inland would give us less
precipitation. Heaviest precip will be on the backside of the low
pressure system later on Sunday afternoon and early evening.

As PWAT`s increase across the region, so will the humidity. High
temperatures today are a bit cooler than yesterday with highs in
the 80s and 90s across the inland valleys and deserts. Expect
high temps to cool off more as we head into Sunday, where
temperatures will be within 5 degrees of normal.

Another weak area of low pressure will move southward as a trough
sets up across the West and an area of high pressure builds over
the NW Pacific. This will keep temperatures very close to normal
for early June with patchy night and morning clouds closer the
coast for Monday and Tuesday. By Wednesday, another weak area
will move down the West Coast over our area funneled between the
high and the low. This will act to keep temperatures rather
unchanged as we move into later in the week with slight warming
across inland areas by the end of next week.

&&

.AVIATION...
312000Z...Coasts/Valleys...Low clouds have mostly cleared from the
inland areas. A few TSRA are moving through coastal San Diego
County, likely to be offshore by 21z. A low thunderstorm threat
continues through the afternoon for both the coastal and valley
areas, with higher confidence for San Diego County. More widespread
chances for SHRA overnight through Sunday morning. Low clouds may
redevelop tonight, with lesser inland extent and only a 20-40%
chance for a CIG at KSAN or other coastal sites, with the best
chance being between 12-16z Sunday. Iso TSRA will possible for the
far eastern valleys and foothills, primarily after 14z Sunday.

Deserts/Mountains...SCT-BKN high clouds at 10,000-20,000ft MSL
through the day. -SHRA possible this afternoon with higher chances
tonight and Sunday morning, especially in San Diego County mtns.
Brief outflow gusts over 25-30kts possible with any developing SHRA
or TSRA. Iso-Sct TSRA possible both this afternoon primarily for the
San Diego Mountains and then more widespread generally after 18z
Sunday. Near zero VIS in any storm with heavy rain, along with
erratic and gusty winds.

&&

.MARINE...
Chance of showers (20-35%) into Sunday across the coastal waters.
Isolated thunderstorms possible through this afternoon, and a Marine
Weather Statement contains further information. Thunderstorm chances
possible again on Sunday. No additional hazardous marine conditions
are expected through Wednesday.


&&

.BEACHES...
A long period south swell will build into the region Sunday, leading
to elevated surf for south and southwest facing beaches of 4 to 6
feet with sets to 7 or 8 feet possible. This will result in higher
rip current risk and locally hazardous swimming conditions. Surf
peaks Monday and gradually diminishes Tuesday through Wednesday. A
Beach Hazard Statement is in effect and contains more information.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement from Sunday morning through Tuesday
     afternoon for Orange County Coastal Areas-San Diego County
     Coastal Areas.

PZ...None.

&&

$$

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