Mesa Grande, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

580
FXUS66 KSGX 171815
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
1115 AM PDT Sun May 17 2026

.SYNOPSIS...
Cooler weather persists through the weekend, with a deeper, more
persistent marine layer and night and morning coastal low clouds
extending well inland and onto the coastal slopes of the
mountains. Southwest to west winds for the mountains and deserts
will gust to 40 to 50 mph through Sunday, with isolated gusts to
65 mph. Gradually warmer, dry weather with generally weak winds
will follow Monday through Thursday, followed by a slight
cooldown from Thursday into Friday.

&&

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

.SHORT TERM (Today through tomorrow night)...
Gusty winds will continue through the day today and through this
evening as low pressure brings winds from the west over the area. As
low pressure shifts further east, winds will ease through Monday.
Strongest winds are in the deserts, desert mountain slopes and
mountain passes with gusts up to 45 to 55 mph, locally up to 60 mph.

Highs today and Monday will be near to just below average for much
of the area. The exception being some areas in the Riverside and San
Bernardino county mountains with highs 5 to 10 degrees below average.

Low clouds from the marine layers influence will stick around
through the day today and are expected to clear Monday morning.

&&

.LONG TERM (Tuesday through Sunday)...
As winds shift to off shore Tuesday, low clouds will stick closer to
the coast, giving us some much needed sunshine in the afternoons at
least through mid-week. Temperatures increase area wide Tuesday,
with daily highs continuing to increase through the week, peaking
Thursday afternoon. Temperatures Thursday will be up to 5 degrees
warmer than average over most of the area. The high deserts will see
temperatures 5-10 degrees above average.


&&

.AVIATION...
171800Z...Coast/Valleys...SCT-BKN clouds with bases 2000+ ft MSL
through the coastal basin. Low clouds should scatter out through
20z, although some may linger in inland valleys through the
afternoon. Low confidence in timing of cigs developing along the
coast, higher confidence that when cigs develop bases will be 2000-
3000 ft MSL. Elevated N/NE winds may prevent cigs from developing at
KONT/KSBD/KSNA. Highest chances of cigs at KSNA are 30-40 percent 04-
12Z Mon. Low clouds will scatter 16-18Z from the valleys to the
coast.

Mountains/Deserts...Gusty north to northwest winds with widespread
30-40 knot surface gusts expected in the deserts, locally up 60
knots in vulnerable mountain passes such as the San Gorgonio Pass.
MOD up/downdrafts and local LLWS in lee of mountains as well as
localized VIS reductions to 4-6SM expected, especially during
periods of strong gusts. Winds weaken after 10z Mon.

&&

.MARINE...
Elevated seas will continue to diminish into the afternoon. No
hazardous marine conditions expected Monday through Friday.

&&

.BEACHES...
A westerly swell from 290 degrees with a 9 to 10 second period is
bringing elevated surf of 4 to 6 feet through Monday morning.
Highest surf on west to northwest facing beaches. The combination of
elevated surf and high tides of 6.5 to 7 feet will result in minor
tidal overflow, especially for beach parking lots and boardwalks.
Surf will start to decrease Monday afternoon.

&&

.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 Monday morning for Orange County
     Coastal Areas-San Diego County Coastal Areas.

     Wind Advisory until 3 AM PDT Monday for Apple and Lucerne
     Valleys-Riverside County Mountains-San Bernardino County
     Mountains-San Diego County Deserts-San Diego County
     Mountains-San Gorgonio Pass near Banning.

PZ...None.

&&

$$

PUBLIC...Villafane
AVIATION/MARINE/BEACHES...CO