471
FXUS66 KSGX 270941
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
241 AM PDT FRI MAR 27 2026
SYNOPSIS
WELL ABOVE AVERAGE TEMPERATURES WILL CONTINUE THROUGH THE WEEKEND.
WIDESPREAD MARINE LAYER LOW CLOUDS THIS MORNING WILL BECOME
PATCHIER OVER THE WEEKEND WITH INCREASING HIGH CLOUDS. COOLER
MONDAY THROUGH WEDNESDAY WITH HIGH TEMPERATURES RETURNING TO
NORMAL. BREEZY ONSHORE WINDS AND A CHANCE OF SHOWERS FOR THE
MOUNTAINS WESTWARD TUESDAY AND WEDNESDAY. MINOR WARMING THURSDAY
THEN MORE SIGNIFICANT WARMING ON FRIDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
LOW CLOUDS HAVE SPREAD INTO THE COASTAL AREAS AND HAVE STARTED TO
MOVE INTO THE FAR WESTERN VALLEYS IN SAN DIEGO COUNTY THIS
EVENING. OTHERWISE SKIES ARE CLEAR. LOW CLOUDS WILL CLEAR BACK TO
THE BEACHES BY LATE MORNING. ANOTHER WARM DAY IS IN STORE AS UPPER
LEVEL HIGH PRESSURE OVER THE SOUTHWEST US EXPANDS SLIGHTLY FURTHER
WEST OVER SO CAL. HIGH TEMPERATURES WILL BE AS MUCH AS 15-20
DEGREES ABOVE NORMAL INLAND, AND AROUND 5-10 DEGREES ABOVE NORMAL
NEAR THE COAST. SEVERAL HIGH TEMPERATURE RECORDS ARE AT RISK OF
BEING BROKEN, MAINLY IN THE MOUNTAINS AND LOW DESERTS. ON
SATURDAY, THE MARINE LAYER WILL BECOME MORE SHALLOW, ALLOWING FOR
MORE WARMING IN THE INLAND COASTAL AREAS AND VALLEYS WHERE HIGH
TEMPERATURES COULD BE CLOSE TO 25 DEGREES ABOVE NORMAL. THE
SHALLOWER MARINE LAYER WILL ALSO INCREASE THE RISK OF FOG,
POTENTIALLY DENSE, IN THE COASTAL AREAS TONIGHT INTO SATURDAY
MORNING.
THE UPPER LEVEL RIDGE BEGINS TO BREAK DOWN ON SUNDAY, BRINGING
MINOR COOLING THOUGH HIGHS WILL REMAIN AROUND 15-20 DEGREES ABOVE
NORMAL INLAND. INCREASING HIGH CLOUDS LATE SATURDAY INTO SUNDAY
MAY DISRUPT MARINE LAYER LOW CLOUDS FROM REDEVELOPING SATURDAY
NIGHT. A WEAK UPPER LEVEL TROUGH MOVES INLAND ACROSS THE PAC NW ON
MONDAY WITH MOSTLY ZONAL FLOW AND CONTINUED COOLING IN SO CAL.
MONDAY IS THE FIRST DAY IN OVER TWO WEEKS THAT NO RECORD HIGH
TEMPERATURES ARE FORECAST TO BE BROKEN.
GLOBAL ENSEMBLES ARE STILL STRUGGLING WITH THE PROGRESSION OF AN
UPPER TROUGH IN THE SOUTHERN STREAM OF THE JET TOWARDS THE MIDDLE
OF NEXT WEEK. AROUND 55% OF THE MEMBERS ARE SLOWER AND KEEP THE
TROUGH OFFSHORE INTO TUESDAY, MEANING LESS COOLING AND DRY
WEATHER. THE OTHER 45% ARE MORE PROGRESSIVE FOR GREATER COOLING
AND AN EARLIER ONSET OF PRECIPITATION. UNCERTAINTY IN THE POSITION
AND AMPLITUDE OF THE TROUGH PERSISTS INTO WEDNESDAY. ALL CLUSTERS
SHOW SOME FORM OF TROUGHING NEAR THE WEST COAST WITH CLUSTER MEANS
CONTAINING SOME PRECIPITATION. THE MOST AMPLIFIED AND WETTEST
CLUSTER ACCOUNTS FOR ABOUT 28% OF THE ENSEMBLE SPACE, WHILE 43%
ARE LOWER AMPLITUDE/LESS WET AND THE REMAINING 29% IS SOMEWHERE IN
BETWEEN. WHILE CURRENT FORECAST CALLS FOR AT LEAST A SLIGHT
CHANCE (15%) OF PRECIPITATION TUESDAY MORNING THROUGH WEDNESDAY
EVENING, THIS WINDOW WILL LIKELY BE NARROWED AND POSSIBLY SHIFTED
ONCE THE TIMING BECOMES MORE CLEAR. OVER A LARGER WINDOW (TUE
MORNING THROUGH THU MORNING) THERE IS AROUND A 50% CHANCE OF AT
LEAST 0.01" FOR THE MOUNTAINS WESTWARD, AND A 25-45% CHANCE OF AT
LEAST 0.10", WITH THE HIGHEST PROBABILITIES ALONG THE COASTAL
MOUNTAIN SLOPES. ENSEMBLES HAVE BEEN TRENDING DRIER OVERALL THE
PAST COUPLE DAYS WITH MEANS BELOW 0.10", SO NOT EXPECTING MUCH AT
THIS POINT. WHAT IS MORE CERTAIN IS THAT IT WILL BE COOLER AND
CLOUDIER WITH BREEZY ONSHORE WINDS IN THE MOUNTAINS AND DESERTS.
WHENEVER THE TROUGH DECIDES TO PROGRESS EASTWARD LATER IN THE
WEEK (THU-FRI), WARMER AND DRIER WEATHER WILL FOLLOW WITH HIGHS
RETURNING TO SLIGHTLY ABOVE NORMAL.
AVIATION
270930Z...LOW CLOUDS AND FOG WILL CONTINUE TO COVER COASTAL AREAS
THIS MORNING. CIGS WILL BE 400-800 FEET MSL WITH TOPS TO 1100 FEET,
AND VIS REDUCED 0-5SM, LOWEST ON MESAS AND HIGHER COASTAL TERRAIN.
SCATTER OUT 15-17Z. LOW CLOUDS WILL REDEVELOP MAINLY NEAR THE COAST,
BUT WILL BE MORE PATCHY AND LATER AFTER 06Z INTO SATURDAY MORNING.
RANDOM AND INTERMITTENT CIGS AROUND 300-700 FEET MSL.
OTHERWISE, MOSTLY CLEAR SKIES AND VFR CONDITIONS TODAY AND TONIGHT.
MARINE
NO HAZARDOUS MARINE CONDITIONS EXPECTED THROUGH TUESDAY.
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...MM
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