Romoland, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

708
FXUS66 KSGX 050409
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
909 PM PDT Sun May 4 2025

.SYNOPSIS...
A area of low pressure has brought scattered showers and
thunderstorms to the High Desert, western mountains, and the
Coachella Valley today, with precipitation chances prevailing into
Monday evening. Very cool temperatures with highs 10 to 20
degrees below normal through Monday. A building area of high
pressure will usher in warmer and drier weather by Wednesday, with
temperatures warming through the weekend.

&&

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

Update: The upper level low is continuing to track slowly towards
the east. A vort max moving down over San Bernardino County is
continuing to allow for some additional rain/snowfall over the Lake
Arrowhead area. This will eventually move south over the Imperial
Empire and as it becomes superimposed over the lower-level showers
near the surface, it could help to enhance these showers an increase
precip amounts over portions of the coastal and inland areas of San
Diego and Riverside counties throughout the remainder of the
evening.

A consensus of the latest high res models reveal an overall
decrease in the probability of precip over the CWA from tonight
through early Tuesday morning, although there could still be some
afternoon showers and thunderstorms developing again over portions
of the higher deserts and mountains, mainly over western San
Bernardino County. There could be a few of these cells also
making their way over the Coachella Valley as well, although most
of these showers (if any were to move over this location) will
likely be more in the form of virga (precip evaporating before
reaching the surface). Still, the possibility exists of some of
the mountain and desert locations picking up some additional
precipitation tomorrow, especially during the afternoon hours,
with a lesser chance for the coastal and inland valleys. That
being said, a developing area of low pressure at the surface over
the SOCAL bight will likely enhance the marine layer during the
morning hours on Tuesday with some drizzle possible, especially
right along the immediate coastal areas. This will continue to
taper off with clearing conditions by later in the day and
slightly warmer temperatures for Tuesday. This will be followed by
a continued warming and drying trend towards the end of the week
and into the weekend, with next Sunday being the warmest day with
temperatures being back above the seasonal average. There is some
indication (even though it is still far out in the forecast period
and therefore subject to change) that there will be another
longwave trough digging back in over the region and will give way
to another cooldown by early next week.

(Previous discussion submitted at 159 PM):

Radar shows ongoing light rain showers have moved into the Coachella
Valley, with isolated thunderstorms over the San Bernardino and
Riverside County Mountains as well as the High Deserts, all of which
will continue through this evening. Any thunderstorms may cause
gusty and erratic winds, and small hail. Meanwhile, visible
satellite imagery places the upper level low responsible for our
precipitation today right along the coast just south of Orange
County, which will continue an eastward trek into the western AZ
desert through early Monday morning. As this low moves across, more
widespread precipitation is expected this afternoon and evening,
with accumulations around 0.10-0.20" for the inland areas, and up to
0.50" for the mountains and deserts where any thunderstorms occur.
Rainfall rates won`t generally exceed 0.25" an hour, but a brief,
heavy downpour with any thunderstorm is not out of the question
given PW values around 0.50-0.75". Snow levels through this event
will be fairly high, around 8000ft today rising to around 9000ft
by Monday, so only the highest locations may see any snow
accumulations.

By sunrise on Monday, most of thee precipitation will be ending, but
wrap-around moisture on the back half of the low along with modest
instability over the deserts may result in a few thunderstorms
developing off the northern desert slopes Monday afternoon and
early evening, generally remaining east of Big Bear. While the
thunderstorm threat cuts off at the mountains, a few light showers
cannot be ruled out for the coastal foothills of the mountains or
valleys on Monday, with any precipitation accumulations expected
to remain below 0.05". Dry conditions return late Monday night and
should prevail for the remainder of the week. Other than the
precipitation, temperatures are quite interesting with extremely
cold highs today and Monday (40s for the mountains, low to mid 60s
for the valleys and coasts, and 70s for the low deserts and
Coachella Valley), but with the departure of the aforementioned
low, upper level ridging quickly builds in this week. Temperatures
climb through Saturday, with highs returning to near normal by
Wednesday, and 5 to 15 degrees above normal by the weekend.

&&

.AVIATION...
050400..Coasts/Valleys/Coastal Slopes... Lingering elevated SHRA
continues to stream in from the north into the Inland Empire from
storms in the high desert this afternoon. Meanwhile, the persistent
low level -SHRA/DZ along coastal San Diego County continues as
well. Cloud bases are quite varied from 1500-3500ft MSL with lower
CIGs and VIS restrictions associated with areas of precipitation.
Both the elevated SHRA and lower level -SHRA/DZ should continue
through the overnight hours, eventually diminishing by 15-18z
Monday. As for the clouds, expecting scattering out along the coasts
by 18-21z Monday, with clouds sticking along the coastal mountain
slopes through the afternoon. Clouds fill back in across the coastal
basin after 00-03z Tuesday, with bases around 1500-2500ft MSL.

Desert Mtn Slopes/Deserts...Gusty west to northwest winds continue
this evening, with gusts gusts 20-30 kt, locally up to 40 kt below
the passes. These winds gradually diminish throughout the overnight
hours, with the only notable gusts (over 20 kts) limited to the
mountain passes and higher peaks. MOD-STG up/downdrafts and areas of
LLWS remains possible over and east of the desert slopes until the
winds diminish tonight. Lingering SHRA from today`s storms remain
possible over deserts this evening, clearing out overnight. Another
round of SHRA possible Monday afternoon, though only about a 15-25%
chance.

&&

.MARINE...
Winds continue to gradually wane over the waters this evening, with
gusts now up to 10-15 kts in the outer waters. Wave heights are also
gradually decreasing, now generally at or below 7ft. Locally steep
waves are possible with periods of 7-10 seconds, but these should
decrease as the combined seas continue to diminish. With this, the
Small Craft Advisory has been allowed to expire. No additional
hazardous marine conditions are expected through Friday.

&&

.BEACHES...
Northwest swell of 5-8 feet with a 7-10 second period continues to
wane this evening and overnight, with surf following suit.
Occasional waves of 6-7 feet remain possible over the next hour or
so but the High Surf Advisory looks on pace to expire at 11 PM PST.
Surf dwindles to 3-5 feet by Monday morning, though a building long
period southwest swell looks to keep surf at 3-5 feet into midweek.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory until 11 PM PDT this evening for San Diego
     County Coastal Areas.

PZ...None.

&&

$$

UPDATE...Stewey
PUBLIC...Zuber
AVIATION/MARINE...Munyan