Rossmoor, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

627
FXUS66 KSGX 251628
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
928 AM PDT Sun May 25 2025

.SYNOPSIS...
Periods of gusty westerly winds in the mountains and adjacent
desert areas each afternoon and evening through Monday. Gradual
warming through the coming week, with day-to-day variations in the
amount of night and morning low clouds and fog west of the
mountains.

&&

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

.Morning Update...

Dry weather will prevail through the rest of the holiday weekend
into much of next week. Low clouds continue to clear at a steady
pace this morning, with San Diego County clearing first. Parts of
Orange County will clear soon with the Inland Empire expected to
clear later this morning. West winds currently near 20-40 mph
across the mountains this morning will increase yet again,
especially in the San Gorgonio Pass this afternoon and evening
with high confidence in wind gusts over 50 mph at times. Latest
guidance brings back low clouds into portions of San Diego County
later this afternoon, with clouds filling in much of the coastal
plain again overnight into Monday morning with patchier low
clouds across the Inland Empire. No changes to the forecast, and
we hope you are enjoying the beautiful holiday weekend weather!

.Previous Forecast Discussion...

The closed upper low is now over eastern NV and will continue to
move east with a transient ridge moving over central and southern
CA through Monday. This will keep the marine layer roughly at its
current depth and daytime temperatures on the rise. Temperatures
today will generally be a few degrees higher than yesterday, and
yet a few degrees higher on Monday. High temps on Monday will
reach the low 80s for the inland valleys and the triple digits in
the lower deserts. These range from slightly below to slightly
above seasonal averages. Locally gusty west winds will continue in
the mtns and deserts each afternoon and evening through Monday,
although they will not be as strong on Monday. Gusts will once
again be in the 50-60 mph range below the mtn passes and 30-40 mph
for the remaining desert slopes and foothills through this
afternoon.

Another low pressure trough develops into a closed upper level low
over SoCal by Tuesday morning. In spite of this, inland temperatures
continue to gradually rise while a deepening marine layer moderates
temperatures near the coast, with increasing low cloud cover
during the nights and mornings. On Tuesday, inland temperatures
will likely be several degrees above seasonal averages, reaching
the mid 80s in the IE.

From mid-week to next weekend, temperatures continue to rise with
Friday looking like it will be the warmest day for inland areas.
By Thursday, yet another closed upper low develops somewhere in
the vicinity of SoCal, however there is significant spread in the
positioning of the upper low which means low confidence in the
details of the forecast as we move into the latter half of the
week. A percentage of ensemble members show the closed upper low
to our south. This implies the potential for easterly winds and
unseasonably high temperatures for areas west of the mountains. If
easterly winds do develop, it could push the marine layer clouds
and fog offshore. For Friday, the National Blend of Models
indicates a 60-80 percent chance of exceeding 95 degrees in the
eastern portion of the IE and about a 30 percent chance in the
western portion. It also shows about a 40 percent chance of
exceeding 105 degrees in the lower deserts and about a 40 percent
chance of exceeding 85 degrees within a few miles of the coast. At
this time of year, these low-latitude closed lows are very
difficult to accurately model so changes are likely.

&&

.AVIATION...
241630Z...Coasts/Valleys...Satellite shows low clouds (based at 2400-
3000ft MSL) rapidly clearing across San Diego County with KSAN and
KCRQ expected to scatter within the hour. Orange County and the
Inland Empire could take until closer to 18z to scatter. Clouds push
inland again tonight, but will be more patchy with better coverage
initially expected for San Diego County and to a lesser extent
Orange County and the Inland Empire. Still, expecting full coverage
through the coastal basin by 12z with similar bases as this morning,
albeit a few hundred feet lower.

Mountains/Deserts...Strong west winds over mountains, passes and
desert slopes with gusts locally to 35-50 kts expected after 23z,
weakening through Monday morning. Mod up/downdrafts in lee of
mountains with very patchy BLDU possible, locally reducing VIS down
to 3-5SM at times. Otherwise, clear skies and VFR conditions
prevail.

&&

.MARINE...
Gusts approach 20 knots Monday afternoon and evening in the outer
coastal waters near San Clemente Island before subsiding early
Tuesday morning. Otherwise, no hazardous marine conditions are
expected through Thursday.

&&

.BEACHES...
Long period (17-18 seconds) south-southwest swell increases
gradually through this morning, with surf of 4-6 feet and high rip
current risk through Monday. Sets up to 7 feet possible along
southwest facing beaches. Surf begins to subside on Tuesday. A Beach
Hazard Statement remains in effect through Monday night and contains
more details. Additionally, this elevated surf combined with
relatively high tides nearing 7ft could lead to localized minor
tidal overflow, peaking Monday evening.

&&

.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 late Monday night for Orange
     County Coastal Areas-San Diego County Coastal Areas.

     Wind Advisory until 3 AM PDT Monday for San Gorgonio Pass near
     Banning.

PZ...None.

&&

$$

UPDATE...APR
PREVIOUS PUBLIC...PG
AVIATION/MARINE/BEACHES...Munyan