360
FXUS66 KSGX 190425
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
925 PM PDT WED JUN 18 2025
SYNOPSIS
HIGH PRESSURE OVER THE REGION THAT HAS AIDED IN HOT INLAND WEATHER
WILL MOVE OFF TO THE EAST BY THURSDAY AND FRIDAY. IN ITS WAKE, AN
AREA OF LOW PRESSURE WILL MOVE SOUTHWARD INTO THE REGION. THIS
WILL BRING MORE NOTICEABLE COOLER WEATHER WITH BREEZIER CONDITIONS
ACROSS THE MOUNTAINS AND DESERTS INTO THE WEEKEND AND EARLY NEXT
WEEK. SUBTLE WARMING IS EXPECTED BY THE MIDDLE OF NEXT WEEK AS
HIGH PRESSURE OFF THE COAST MOVES CLOSER TO OUR AREA.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
UPDATE: THE RIDGE IS BEGINNING TO SHIFT MORE TOWARDS THE EAST NOW
AND ALLOWING FOR THE TROUGH UPSTREAM TO CONTINUE TO TRANSITION EVER
SO SLOWLY TOWARDS THE REGION. THIS WILL ALLOW FOR AN INCREASE OF
WINDS AND ALSO A MORE SUBSTANTIAL PUSH OF THE ONSHORE FLOW BY
TOMORROW EVENING. THERE WILL ALSO BE WINDS INCREASING OUT OF THE
SOUTHWEST OVER THE HIGH DESERTS AND INCREASED GAP FLOW THROUGH SAN
GORGONIO/BANNING PASS, ALTHOUGH IT STILL APPEARS AS IF THESE
WINDS SHOULD PRIMARILY REMAIN BELOW THE THRESHOLD...DESPITE A FEW
LOCALIZED GUSTS EXCEEDING IT. TEMPERATURES WILL CONTINUE TO COOL
DOWN WITH THE TROUGH FURTHER DEEPENING AND MOVING OVER THE REGION
GOING INTO THE WEEKEND, ESPECIALLY WITHIN THE IMPERIAL VALLEY. THE
MARINE LAYER WILL ALSO RISE AND THICKEN UP A BIT. THIS WILL BE A
VERY DRY TROUGH AND LIKELY NOT HAVE ANY PRECIPITATION WITH IT,
ALTHOUGH THERE COULD BE SOME AREAS OF DRIZZLE POSSIBLE FOR THE
COASTAL AND INLAND AREAS BY SATURDAY NIGHT INTO SUNDAY MORNING.
THE PATTERN LOOKS TO REMAIN PRETTY CONSISTENT WITH A TROUGH OVER
THE WESTERN STATES INTO THE EARLY PART OF NEXT WEEK, AND THEN THE
OVERALL CONSENSUS OF THE ENSEMBLES HAS THE RIDGE BEGINNING TO
FLATTEN OUT TOWARDS THE END OF NEXT WEEK, WITH TEMPERATURES
GRADUALLY WARMING UP FROM WEDNESDAY THROUGH NEXT WEEKEND.
(PREVIOUS DISCUSSION SUBMITTED AT 217 PM):
A 592DM AREA OF HIGH PRESSURE IS CURRENTLY OVER ARIZONA IS
PROVIDING ANOTHER HOT AFTERNOON FOR INLAND AREAS. CURRENT
TEMPERATURES ACROSS THE MOUNTAINS AND INLAND EMPIRE ARE WELL INTO
THE 80S AND 90S WITH TRIPLE DIGIT HEAT ACROSS THE LOWER DESERTS.
THE MARINE LAYER IS EXPECTED TO DEEPEN SLIGHTLY OVERNIGHT,
PROVIDING A GREATER CHANCE OF CLOUD COVER BY MORNING ACROSS THE
COASTAL AREAS AND ADJACENT VALLEYS OF ORANGE AND SAN DIEGO
COUNTIES. THIS MAY ALSO LEAD TO FOGGY CONDITIONS OVER ELEVATED
TERRAIN AS WELL.
A LARGE AREA OF LOW PRESSURE OFF THE COAST OF BRITISH COLUMBIA
WILL PUSH SOUTHWARD INTO THE WEEKEND. HEIGHTS ARE EXPECTED TO
LOWER ON THURSDAY, WHERE TEMPERATURES WILL BE KNOCKED DOWN A FEW
DEGREES FROM TODAY. THE LOW WILL PUSH FURTHER SOUTH INTO THE GREAT
BASIN BY FRIDAY AND SATURDAY, FURTHER COOLING US OFF. HIGHS 5 TO
10 DEGREES ABOVE NORMAL TODAY WILL GO TO 5 TO 10 DEGREES BELOW
NORMAL BY SATURDAY. CONFIDENCE IS HIGH THAT AREAS WEST OF THE
MOUNTAINS WILL MAINLY BE IN THE 60S NEAR THE COAST, 70S IN MUCH OF
THE VALLEYS, WITH SOME LOWER 80S IN THE INLAND EMPIRE. THE SYSTEM
WILL BRING ELEVATED WIND GUSTS TO THE MOUNTAINS AND DESERTS EACH
DAY, MAINLY NEAR 25-40 MPH, LOCALLY HIGHER IN THE SAN GORGONIO
PASS. THE MARINE LAYER WILL SIGNIFICANTLY DEEPEN BY THE WEEKEND AS
WELL, WHERE CLOUDS AND FOG WILL PUSH INTO MUCH OF THE COASTAL
BASIN EACH NIGHT AND MORNING.
THE TROUGHING PATTERN STICKS AROUND INTO EARLY NEXT WEEK, THOUGH
NOT AS POTENT, WHICH WILL HELP TO WEAKEN WINDS SLIGHTLY. THE
MIDDLE OF THE WEEK STAYS DRY AS WEAK HIGH PRESSURE OFF THE COAST
BEGINS TO HAVE GREATER INFLUENCE OVER THE AREA. THIS WILL BRING
SOME WARMING TO THE AREA, THOUGH HIGHS DO NOT LOOK TOO FAR FROM
AVERAGE.
AVIATION
190315Z....COAST/VALLEYS...SATELLITE SHOWS LOW CLOUDS HAVE JUST
BEGUN MOVING INLAND, WITH BASES 1200-1400FT MSL AND TOPS TO 1800FT
MSL. CLOUDS WILL CONTINUE TO FILTER INLAND THROUGH THE NIGHT,
REACHING KSNA LIKELY BY 06Z AND ENCROACH AT KONT BY 11Z. BASES WILL
FALL A BIT, CLOSER TO 800-1100FT MSL BY 08Z AND VIS MAY FALL TO 1-
3SM. CHANCES OF A CIG AT KONT ANYTIME BETWEEN 11Z-16Z ARE 15-25%.
CLOUDS WILL CLEAR TO THE COAST BY 17Z, AND POTENTIALLY SOME CLEARING
OFFSHORE BY 19Z. LOW CLOUDS DEVELOP AGAIN THURSDAY NIGHT AND PUSH
INLAND AFTER 01Z WITH SLIGHTLY HIGHER BASES.
INLAND VALLEYS/MOUNTAINS/DESERTS
CLEAR SKIES AND UNRESTRICTED VIS
THROUGH THURSDAY.
MARINE
NORTHWEST WINDS MAY GUST CLOSE TO 20 KNOTS NEAR SAN CLEMENTE ISLAND
FRIDAY AFTERNOON AND EVENING. OTHERWISE, NO HAZARDOUS MARINE
CONDITIONS ARE EXPECTED THROUGH 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.
UPDATE...STEWEY
PUBLIC...APR
AVIATION/MARINE...ZUBER
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