073
FXUS66 KSGX 290419
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
919 PM PDT MON JUL 28 2025
SYNOPSIS
A STABLE WEATHER PATTERN WILL CONTINUE ACROSS THE REGION WITH A
TROUGH TO THE NORTH AND HIGH PRESSURE TO THE SOUTH. THIS WILL KEEP
TEMPERATURES NEAR NORMAL THROUGH THE WEEK WITH DRY WEATHER. THE
MARINE LAYER WILL HELP TO BRING IN LOW CLOUDS FOR THE COAST AND
WESTERN VALLEYS EACH NIGHT AND MORNING.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
UPDATE: THE MARINE LAYER IS STILL REMAINING MOSTLY OFFSHORE AT THIS
HOUR OF THE EVENING. MOST OF THESE CLOUDS ARE HUGGING THE COASTLINE
OF SAN DIEGO COUNTY. THESE CLOUDS WILL CONTINUE TO FILL INTO
PORTIONS OF THE INLAND VALLEYS, ALTHOUGH NOT EXPECTING IT TO EXTEND
QUITE AS FAR EASTWARD SINCE THE CEILINGS WILL BE LOWER NIGHT BY A
COUPLE HUNDRED FEET FROM WHERE THEY WERE LAST NIGHT. THIS WILL
CONTINUE TO BE THE CASE, WITH THE MARINE LAYER BECOMING LOWER AND
THINNER FOR THE NEXT COUPLE OF DAYS AS HIGH PRESSURE CONTINUES TO
BUILD IN STRONGER. THERE WILL ALSO BE A GRADUAL WARMING TREND DUE TO
THIS AS WELL THROUGH WEDNESDAY, THEN THERE WILL BE A SLIGHT COOLDOWN
WITH TEMPERATURES REMAINING NEARLY STEADY THROUGH THE WEEKEND INTO
EARLY NEXT WEEK AS HEIGHTS ALOFT REMAIN SIMILAR. THE OVERALL
TROUGHING UPSTREAM TO THE NORTHWEST OF THE REGION IS GOING TO FORCE
MONSOONAL MOISTURE TO REMAIN CONFINED TO THE EAST OVER ARIZONA
THROUGHOUT THE NEXT WEEK, WITH VIRTUALLY A ZERO CHANCE OF ANY
DEVELOPMENT OF AFTERNOON THUNDERSTORMS OVER THE MOUNTAINS THROUGH
NEXT MONDAY.
(PREVIOUS DISCUSSION SUBMITTED AT 139 PM):
SOCAL IS CURRENTLY IN BETWEEN TWO LARGE PRESSURE SYSTEMS ACROSS
NORTH AMERICA: ONE DOMINANT RIDGE OF HIGH PRESSURE OVER THE
SOUTHERN PLAINS BRINGING RELENTLESS HEAT AND AN AREA OF LOW
PRESSURE IN THE GULF OF ALASKA, BRINGING COOL AND WET CONDITIONS
TO THE NORTHERN WEST COAST. THIS HAS BROUGHT US INTO A WEAK
TROUGHING PATTERN, WHICH WILL CONTINUE TO BRING VERY BENIGN
WEATHER THIS WEEK. HIGH PRESSURE ACROSS THE SOUTHERN PLAINS WILL
EXPAND FURTHER WEST INTO BAJA CALIFORNIA, REMAINING THERE THROUGH
THE WEEK AS BROAD TROUGHING STICKS OVER THE WEST. THIS WILL LEAD
TO VERY MINOR DAY TO DAY CHANGES IN THE WEATHER PATTERN FROM
TUESDAY INTO THE END OF THE WEEK. THE MARINE LAYER WILL THIN
SLIGHTLY BY THE MIDDLE OF THE WEEK, KEEPING NIGHT AND MORNING LOW
CLOUDS CONFINED TO THE COAST AND VALLEYS OF SAN DIEGO AND ORANGE
COUNTIES. DIURNAL SOUTH AND WEST WINDS WILL OCCUR ACROSS THE
DESERT SLOPES AND DESERTS, MAINLY BELOW 35 MPH EACH DAY.
ENSEMBLE MODELS SHOW MODEST AGREEMENT ON THE RIDGE TO THE SOUTH
BECOMING A BIT STRONGER BY THE WEEKEND, WHICH WOULD LEAD TO A
SUBTLE RISE IN TEMPERATURES. HOWEVER, MODELS SHOW THIS MAY NOT
LAST TOO LONG AS THE TROUGH TO THE NORTH MAY BE FAVORED BY EARLY
NEXT WEEK. ENSEMBLE MODELS ALSO SHOW A POTENTIAL INCREASE IN
PRECIPITABLE WATER AMOUNTS BY THE EARLY TO MIDDLE PORTION OF NEXT
WEEK, WHICH COULD BRING A NON ZERO CHANCE OF MONSOON THUNDERSTORMS
INTO THE PICTURE IF HIGH PRESSURE SETS UP OVER THE SOUTHWEST.
THIS IS STILL QUITE A WAYS OUT, SO CONTINUE TO MONITOR THE
FORECAST FOR UPDATES.
AVIATION
282030Z....COAST/WESTERN VALLEYS...LOW CLOUDS TO PUSH ASHORE AFTER
02Z AND LOCALLY INTO WESTERN VALLEYS AFTER 06Z. BASES SHOULD BE 1200-
1600 FEET MSL, TOPS TO 2000 FEET, AND LOCAL VIS REDUCED 1-5SM ON
HIGHER TERRAIN. SCATTER OUT TUESDAY 15-17Z.
INLAND VALLEYS/MOUNTAINS/DESERTS
MOSTLY CLEAR WITH VFR CONDITIONS
THROUGH TUESDAY.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH SATURDAY.
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...CO
AVIATION/MARINE...WESTERINK
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