176
FXUS66 KSGX 260457
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
857 PM PST TUE NOV 25 2025
SYNOPSIS
ABOVE NORMAL HIGH TEMPERATURES AND WEAK TO LOCALLY MODERATE
OFFSHORE FLOW THROUGH THURSDAY, WITH WINDS PEAKING ON WEDNESDAY.
COOLER FRIDAY THROUGH EARLY NEXT WEEK WITH A 15-25% CHANCE FOR
LIGHT PRECIPITATION SUNDAY INTO EARLY MONDAY. AS THE SYSTEM MOVES,
A WARMING AND DRYING TREND SETS UP WITH ANOTHER ROUND OF OFFSHORE
FLOW DEVELOPING AS EARLY AS MONDAY MORNING.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
SKIES REMAIN CLEAR THIS EVENING UNDER WEAK OFFSHORE FLOW. DEW
POINTS ARE STILL HIGH ENOUGH OVER THE COASTAL AREAS FOR PATCHY
RADIATIONAL FOG TO DEVELOP DURING THE EARLY PART OF THE NIGHT, BUT
ANY FOG SHOULD DISSIPATE BY EARLY MORNING AS OFFSHORE FLOW
STRENGTHENS. NORTHEAST TO EAST WINDS WILL PEAK LATE WEDNESDAY
MORNING THROUGH EARLY THURSDAY EVENING WITH GUSTS AROUND 25-40 MPH
THROUGH THE USUAL WIND PRONE PASSES, CANYONS , AND COASTAL
SLOPES/FOOTHILLS. THE COMBINATION OF OFFSHORE FLOW AND AN UPPER
LEVEL RIDGE OF HIGH PRESSURE MOVING OVERHEAD AND STRENGTHENING
WILL CONTINUE THE WARMING TREND ON WEDNESDAY WHEN HIGHS WILL BE AS
MUCH AS 8 TO 12 DEGREES ABOVE NORMAL IN THE VALLEYS, AND AROUND
5-8 DEGREES ABOVE NORMAL ELSEWHERE. INCREASING OFFSHORE FLOW
TOMORROW WILL ALSO LEAD TO VERY DRY CONDITIONS WITH AFTERNOON
RELATIVE HUMIDITY OF AROUND 10-15% FOR THE VALLEYS AND MOUNTAINS.
AN UPPER LEVEL SHORT WAVE TROUGH MOVES INTO THE PAC NW ON
THANKSGIVING, CAUSING THE UPPER RIDGE TO BREAK DOWN. SURFACE
PRESSURE GRADIENTS BEGIN TO RELAX AS WELL, LEADING TO WEAKER
OFFSHORE WINDS AND LOWER (BUT STILL ABOVE NORMAL) HIGH
TEMPERATURES. HIGH RES GUIDANCE SHOWS A COASTAL EDDY SPINNING UP
ON THURSDAY NIGHT AS WE TRANSITION BACK TO ONSHORE FLOW, WHICH
WILL AID THE DEVELOPMENT OF LOW CLOUDS AND FOG ALONG THE COAST.
THE AFOREMENTIONED SHORT WAVE TROUGH DIGS SOUTHEAST THROUGH THE
GREAT BASIN ON FRIDAY WITH TROUGHING DEVELOPING ACROSS THE ENTIRE
CONUS FOR MORE CONSIDERABLE COOLING ACROSS THE REGION.
THIS COOLING TREND CONTINUES ON SATURDAY AS A SECOND SHORT WAVE
DROPS OUT OF THE GULF OF ALASKA AND INTO THE PAC NW. DESPITE ONLY
BEING 5 DAYS OUT, GLOBAL ENSEMBLES ARE STILL STRUGGLING WITH THE
PROGRESSION OF THIS TROUGH AND WHETHER OR NOT IT WILL DIG FAR
ENOUGH SOUTHWEST/BECOMING POSITIVELY TILTED TO BRING US
PRECIPITATION OR JUST REMAIN AN INSIDE SLIDER. AROUND 80% OF THE
ENSEMBLE MEMBERS DIG THE LOW FAR ENOUGH SOUTHWEST TO BRING
PRECIPITATION BY EARLY SUNDAY MORNING, WHILE 20% ARE FAR INSIDE
AND DRY. OF THE 80% THAT DO SHOW PRECIPITATION, THE AVERAGE 24 HR
PRECIPITATION (ENDING 4 PM SUNDAY) FROM THESE MEMBERS IS LESS
THAN 0.20". AROUND 17% ARE MUCH WETTER, WITH THE 24 HR AVERAGE
CLOSER TO 0.50". THE SPLIT IN ENSEMBLES STAYS AROUND THE SAME FOR
MONDAY, WITH THE 20% STILL INSIDE, AROUND 35% CONTINUING TO DIG
THE TROUGH SOUTHWEST (OR EVEN TRYING TO CLOSE IT OFF) AND
CONTINUING WET WEATHER INTO MONDAY, AND ANOTHER 25% SOMEWHERE IN
BETWEEN WITH LIGHT PRECIPITATION ON MONDAY. NBM PROBABILITIES
AREN'T PROMISING, WITH ONLY A 25% CHANCE OF STORM TOTAL OF 0.10"
OR MORE FOR THE COASTS AND VALLEYS, AND A 40% CHANCE OF 0.10" OR
MORE FOR THE MOUNTAINS. THE TRACK OF THE SYSTEM AND ANY COLD
AIR ADVECTION WITH IT WILL MEAN HUGE DIFFERENCES FOR THE SNOW
LEVEL AS WELL, WHICH COULD REASONABLY RANGE ANYWHERE FROM AROUND
5000 TO 7000 FT.
BEHIND THIS TROUGH (ASSUMING IT EVEN SHOWS UP IN THE FIRST PLACE),
WEAK TO POTENTIALLY MODERATE SANTA ANA WINDS WILL DEVELOP AGAIN
FOR WARMER AND DRIER CONDITIONS, AT LEAST UNTIL THE NEXT TROUGH
WITH A QUESTIONABLE TRACK POTENTIALLY DIGS SOUTH AND BRINGS
ANOTHER ROUND OF PRECIPITATION LATER IN THE WEEK.
AVIATION
250400Z...COASTS...VFR VERY LIKELY THROUGH THE PERIOD, WITH A 20%
CHANCE FOR CIGS AND VIS RESTRICTIONS AT THE COAST. HIGHEST CHANCES
OF CIGS/VIS RESTRICTIONS ARE 05-12Z. IF CIGS DEVELOP BASES WOULD BE
300-500 FT, WITH POTENTIAL VIS RESTRICTIONS 1/4-1 MILE. COVERAGE OF
ANY CIGS OR VIS REDUCTIONS WOULD BE PATCHY AND CLEAR BY 14Z.
VALLEYS/MOUNTAINS/DESERTS...VFR CONDITIONS EXPECTED THROUGH TONIGHT.
E TO NE WINDS LOCALLY GUSTING 25-40 KT ALONG COASTAL SLOPES OF THE
MTNS WILL EXPAND TO INCLUDE ADJACENT FOOTHILLS AND PORTIONS OF THE
INLAND EMPIRE AFTER 13Z. AREAS OF LLWS/LOW-LEVEL TURBULENCE ALONG
FOOTHILLS/WEST MTN SLOPES.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH MOST OF
SATURDAY. THERE IS THE POTENTIAL FOR ELEVATED WINDS AND SEAS LATE
SATURDAY INTO EARLY NEXT WEEK DUE TO AN APPROACHING STORM SYSTEM,
BUT THE FORECAST REMAINS UNCERTAIN; STAY TUNED FOR UPDATES.
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...SS
AVIATION/MARINE...CO
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