San Miguel, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

783
FXUS66 KSGX 150415
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
915 PM PDT Mon Jul 14 2025

.SYNOPSIS...
Cooler for tomorrow into Wednesday, with high temperatures as
much as 8 to 12 degrees below average for the valleys and near
seasonal averages for the deserts. For Thursday and Friday, a
weak upper level low pressure from the south will bring an
increase in monsoonal moisture with a chance of afternoon showers
and thunderstorms, mainly for the mountains and high desert with
the better chances on Friday. Chances will slowly decrease during
the weekend as the monsoonal moisture slowly decreases. Night and
morning coastal low clouds will spread into the western valleys
late each night.

&&

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

This evening...The marine layer remains at a fairly consistent
depth and low clouds are increasing in coverage over the coastal
areas and spreading inland. High-resolution models indicate that
the low clouds will spread as much as 15-20 miles inland by
sunrise before clearing back to the coast in similar fashion to
today. High temperatures today were generally near or a little
below seasonal averages, even in the inland valleys and lower
deserts.

From previous discussion...
The dominant high pressure ridge remains in place, although there
is now more influence from the troughing upstream which has
allowed for a cooldown to begin today that will continue into
Wednesday, with temperatures gradually dropping off and becoming
10 to 15 degrees cooler than the seasonal average for the inland
valleys as the onshore flow becomes more enhanced. For the high
deserts and the lower deserts which are prone to gap flow winds,
during the afternoon, winds will begin to strengthen and become
gusty during the afternoon hours, although should remain below the
threshold of wind advisory criteria. By Wednesday, highs will
only make it into the low to mid 80s for most locations within the
Inland Empire (IE). The marine layer will also continue to
slightly lift and thicken up for the overnight hours during this
period in the forecast, with a very slight chance of there being
some very light drizzle, especially for the inland areas during
the early morning hours. There could also be some patchy fog as
well within some of the wind-sheltered inland areas.

A weak upper level low south of the region will begin to slide
more to the north on Thursday. In the meantime, there will be an
area of high pressure centered over Arizona. This will allow for
mid to upper level winds to turn more southeasterly and result in
some of the monsoonal moisture from Mexico to be advected up over
SOCAL along with some weak upper level disturbances that will
allow for a chance of thunderstorms over the mountains and deserts
beginning on Thursday. There could be a hindrance to thunderstorm
development on Thursday though, depending on how much mid-level
cloud coverage moves over during the morning hours, which might
inhibit daytime heating. By Friday, there will be more moisture
advected up over the area and further north, although the mid-
level flow will still be very weak out of the southeast at the 700
mb level. This is alluding to there being the best chance of
thunderstorms on this day during the afternoon hours. In addition,
given the weak mid-level flow, some of these storms may become
stationary (or nearly stationary), which may lead to potential
flash flooding issues, especially if one of these storms becomes
situated right over a burn scar area.

By Saturday, the U/L low is going to begin to propagate further
towards the northeast and draw some of the moisture further towards
the east in the process. The ridge is also going to slightly build
into the weekend. As the U/L continues to move out of the region and
the mid level flow turns back to being more out of the southwest,
that will help to suppress thunderstorm development as drier air
aloft replaces the more moist and unstable southeasterly flow,
allowing for a lessening of probability of storms over the mountains
and deserts for both days, especially Sunday. The drying and slight
warming trend will continue into early next week.

&&

.AVIATION...
150335Z....Coast/Valleys...Low clouds near 1000-1500 ft MSL will
slowly move inland this evening, further into the valleys overnight.
Confidence is moderate to high on timing for low clouds to move into
VCTY KONT around 11Z Tue. Other areas of the Inland Empire will see
vis restrictions 4-6SM in HZ/BR 10-16Z Tue. Clouds will scatter back
to the coast with slightly better chances of clearing (65% chance at
KSAN, higher at KSNA). Cigs of similar bases returning to most of
the same areas by Tuesday night.

Mountains/Deserts...Mostly clear skies with unrestricted VIS through
Tuesday night.

&&

.MARINE...
No hazardous marine conditions expected through Saturday.

&&

.BEACHES...
A moderate period south-southwesterly swell (2-3 feet at 15-17
seconds) will generate elevated surf and a high risk of rip currents
Wednesday and Thursday. Surf of 3-5 feet expected with sets to 6
feet possible, primarily on southerly facing beaches. Swell and surf
will begin to lower on Friday.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.

&&

$$

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