487
FXUS66 KSGX 110904
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
204 AM PDT SAT APR 11 2026
SYNOPSIS
LOW PRESSURE SYSTEMS WILL IMPACT THE REGION THROUGH MONDAY. THESE
ARE GOING TO BE ACCOMPANIED BY COOLER, WETTER. AMD WINDIER
WEATHER. A CHANCE FOR LIGHT SHOWERS WILL OCCUR TONIGHT INTO
SATURDAY MORNING. THESE WEATHER SYSTEMS WILL ALSO BRING THE CHANCE
OF LIGHT TO MODERATE RAINFALL AND HIGH ELEVATION SNOW. THE
HEAVIEST RAINFALL AND MOUNTAIN SNOWFALL IS EXPECTED ON SUNDAY,
WHERE THERE IS A SLIGHT CHANCE OF THUNDERSTORMS WEST OF THE
MOUNTAINS. THIS LOW PRESSURE SYSTEM MAY LINGER OVER THE AREA INTO
MONDAY, BRINGING ADDITIONAL LIGHT SHOWERS. DRIER AND SLIGHTLY
WARMER WEATHER IS EXPECTED BY THE MIDDLE AND END OF NEXT WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
TODAY THROUGH TOMORROW NIGHT...
ONSHORE FLOW OUT OF THE SOUTHWEST IS BECOMING ENHANCED BY TROUGHING
UPSTREAM WHICH IS ADVANCING TOWARDS THE REGION. THIS HAS ALLOWED FOR
THE MARINE LAYER TO BECOME MORE ELEVATED AND SOMEWHAT DISPERSED THIS
NIGHT, WITH BEST COVERAGE ALONG THE COASTAL-FACING SLOPES. AS THE
FIRST ASSOCIATED SHORTWAVE WITH THIS TROUGH PROPAGATES OVER SOCAL
TODAY, THERE IS A SLIGHT CHANCE OF A FEW SHOWERS DEVELOPING,
ESPECIALLY AGAINST THE FOOTHILLS AND COASTAL-FACING SLOPES. ANY
MEASURABLE PRECIP THAT FALLS WILL LIKELY BE GENERALLY LESS THAN A
TENTH OF AN INCH, AND POSSIBLY ONLY UP TO A QUARTER OF AN INCH
LOCALLY FOR SOME OF THE MOUNTAINS. HOWEVER, THE ONLY REAL NOTABLE
IMPACT FROM THIS TODAY WILL BE MUCH COOLER TEMPERATURES AND GUSTY
WINDS.
IT WILL BE THE SECONDARY LOW DEEPENING AND PUSHING THROUGH BY
LATER THIS EVENING INTO SUNDAY THAT WILL PROVIDE A BETTER CHANCE OF
SHOWERS. THERE WILL ALSO BE ENOUGH INSTABILITY WITH THE U/L LOW
FEATURE ASSOCIATED WITH THIS THAT IT MAY ALLOW FOR THERE TO BE A FEW
THUNDERSTORMS. BETTER PRECIPITATION AMOUNTS ARE EXPECTED TOMORROW,
WITH AMOUNTS OF GENERALLY A QUARTER TO A HALF AN INCH FOR THE
COASTAL TO INLAND AREAS, AND HIGHER TO AROUND THREE QUARTERS OF AN
INCH FOR THE COASTAL SLOPES AND FOOTHILLS. AMOUNTS WILL TYPICALLY BE
FROM A HALF TO AN INCH FOR THE MOUNTAINS, ALTHOUGH THE COASTAL-
FACING SLOPES OF THE SAN BERNARDINO MOUNTAINS MAY RECEIVE LOCALLY
HIGHER AMOUNTS UP TO 1.5 INCHES. FOR ELEVATIONS ABOVE 5000 FT, THERE
MAY ALSO BE SNOW ACCUMULATIONS RANGING FROM A DUSTING, UP TO 2
INCHES AROUND THE VICINITY OF BIG BEAR LAKE. WINDS WILL ALSO BE
RATHER STRONG AND GUSTY, ESPECIALLY ACROSS THE HIGHER TERRAIN AND
WITHIN THE WIND-PRONED AREAS, ALTHOUGH STRONGEST GUSTS FOR THE MOST
IMPACTED AREAS WILL GENERALLY BE BETWEEN 45 TO 50 MPH, AND SHOULD
PRIMARILY BE BELOW WIND ADVISORY CRITERIA. A MOUNTAINTOP INVERSION,
COUPLED WITH A WEAK MOUNTAIN WAVE SETUP, WILL HELP TO ENHANCE
WINDS SLIGHTLY MORE DURING THE EARLY MORNING HOURS ON SUNDAY, AND
WINDS MAY PEAK OVER CRITERIA ON THE LEEWARD SIDE WITHIN THE LOWER
DESERTS FOR A FEW HOURS DURING THIS TIMEFRAME UNTIL THE WINDS
BETTER MIX BY LATER IN THE MORNING. AGAIN, THIS WILL LIKELY BE
SHORT-LIVED, BUT MAY PRODUCE SOME BLOWING DUST AS A RESULT ACROSS
SOME OF THE LOWER DESERT LOCATIONS DOWNWIND OF THESE STRONGER GAP
FLOW WINDS THROUGH THE PASSES. SUNDAY WILL ALSO HAVE MUCH STRONGER
COLD AIR ADVECTION BEHIND THIS SYSTEM, WITH RAPIDLY DROPPING SNOW
LEVELS BY LATER IN THE EVENING, AND HIGHS BEING THE COLDEST OF
THE WEEK.
MONDAY THROUGH FRIDAY...
BY MONDAY, THE SECONDARY MAJOR SHORTWAVE TROUGH IS GOING TO CONTINUE
TO EXIT THE REGION, WITH LINGERING SHOWERS TAPERING OFF THROUGHOUT
THE DAY, MAINLY FOR THE COASTAL-FACING SLOPES. DRIER CONDITIONS WILL
RETURN BY LATER IN THE EVENING ON MONDAY AND GOING INTO TUESDAY AS
WEAK RIDGING ALOFT PROPAGATES OVERHEAD, WHICH WILL FOLLOW INTO
WEDNESDAY WITH DRIER CONDITIONS REMAINING IN PLACE THROUGH THEN.
TEMPERATURES WILL STILL BE QUITE CHILLY ON MONDAY, WITH SOME OF THE
MOUNTAIN LOCATIONS BEING AS MUCH AS 15 DEGREES BELOW AVERAGE, BUT
THEN REBOUND QUITE NICELY WITH NOTABLY WARMER HIGH TEMPS FOR TUESDAY
AND WEDNESDAY. DETERMINISTIC MODELS DO REFLECT GENERAL AGREEMENT
WITH ANOTHER TROUGH DEEPENING OVER THE GREAT BASIN REGION THURSDAY
INTO FRIDAY, WHICH WILL LIKELY JUST INFLUENCE US WITH MORE WINDS IN
SOCAL, ALTHOUGH THIS COULD ALLOW FOR THERE TO BE SOME SHOWERS WEST
OF THE MOUNTAINS, AS WELL AS A REINFORCEMENT OF COOLER TEMPERATURES
ON THURSDAY. THIS WILL TRANSLATE TO A PERSISTENCE OF THE MARINE
LAYER AND ONSHORE FLOW PREDOMINANTLY THROUGHOUT THE WORK WEEK, WITH
TEMPERATURES PRIMARILY BEING BELOW THE SEASONAL AVERAGE FOR THIS
TIME OF YEAR.
AVIATION
110430Z...COASTS/VALLEYS...BKN-OVC CLOUDS WITH BASES 1500-3000 FT
MSL ARE EXPECTED SPREAD INLAND THROUGH 09Z. SPOTTY -SHRA POSSIBLE
THROUGH 19Z SAT, BRINGING LOCALLY MVFR CIGS AND VIS 4-6 SM. ANY LOW
CLOUD COVER WILL CLEAR 16-19Z SAT. BKN-OVC CIGS EXPECTED TO DEVELOP
AFTER 03Z SAT, BUT LOW CONFIDENCE IN CIGS LOWER THAN 2000 FT MSL.
MOUNTAINS/DESERTS
WEST TO SOUTHWEST WINDS WITH GUSTS 35-50 KT
THROUGH PASSES, ALONG DESERTS SLOPES AND LOCALLY INTO THE DESERTS.
LOCAL AREAS BLDU (VIS 3-5SM) EXPECTED. MODERATE UP/DOWNDRAFTS IN LEE
OF MTNS. WIND GUSTS RELAX BY 09Z SATURDAY, BUT ARE EXPECTED TO PICK
BACK UP AGAIN AFTER 20Z SAT AFTERNOON AT A SIMILAR SPEED.
MARINE
THERE IS A SLIGHT CHANCE OF THUNDERSTORMS SUNDAY AFTERNOON.
ADDITIONALLY THERE WILL BE PERIODS OF INCREASED NORTHWEST WINDS WITH
GUSTS 15 TO 20 KT AND CHOPPY SEAS THAT COULD GENERATE HAZARDOUS
CONDITIONS THROUGH THE DAY SUNDAY.
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...STEWEY
AVIATION/MARINE...CSP
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