573
FXUS66 KLOX 142118
AFDLOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
218 PM PDT SUN SEP 14 2025
SYNOPSIS
14/102 PM.
HIGH PRESSURE ALOFT CENTERED OVER NORTHERN MEXICO WILL EXPAND INTO
THE STATE AND CONTINUE A WARMING TREND THROUGH AT LEAST TUESDAY.
AREAS OF NIGHT THROUGH MORNING LOW CLOUDS AND FOG WILL CONTINUE
FOR MANY COAST AND COASTAL VALLEYS THROUGH TUESDAY. MONSOONAL
MOISTURE WILL SPREAD INTO THE AREA BETWEEN TUESDAY AND WEDNESDAY
AND BRING THE POSSIBILITY OF SHOWERS AND THUNDERSTORMS FOR MID-TO-
LATE THIS WEEK. A VERY WARM AND HUMID AIR MASS IS LIKELY TO
SETTLE INTO THE REGION DURING THIS PERIOD.
SHORT TERM (TDY-WED)
14/157 PM.
A QUIET WEATHER PATTERN WILL CONTINUE THROUGH TUESDAY WITH THE
BIGGEST IMPACT BEING THE INCREASING HEAT ACROSS THE AREA. BUILDING
HIGH PRESSURE OVER THE NEXT 24 TO 48 HOURS WILL WARM UP
TEMPERATURES SEVERAL DEGREES, ESPECIALLY INLAND. BASED ON THE
CURRENT FORECAST IT'S A VERY BORDERLINE HEAT ADVISORY SITUATION
FOR PARTS OF LA COUNTY TUESDAY AND WEDNESDAY, BUT WITH THE BIG
CAVEAT BEING THE INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS
WEDNESDAY AND BEYOND AS THE REMNANTS OF NEWLY CROWNED TROPICAL
STORM MARIO MOVE NORTH INTO OUR AREA. THE ADDED MOISTURE ALOFT AND
POTENTIAL CLOUDS AND SHOWERS ON WEDNESDAY SIGNIFICANTLY
COMPLICATES THE HEAT ADVISORY CHANCES SO WILL HAVE TO TAKE IT DAY
BY DAY AND SEE HOW THE PATTERN EVOLVES. WILL RE-EVALUATE THE HEAT
ADVISORY POTENTIAL ON MONDAY. AT THE VERY LEAST IT WILL BECOME
INCREASINGLY MUGGY TUESDAY AND ESPECIALLY WEDNESDAY AS PW'S
INCREASE TO BETWEEN 1.5 AND 2" WHICH WOULD BE ABOVE THE 95TH
PERCENTILE CLIMATOLOGICALLY.
CONSIDERING THAT MARIO HAS ONLY COME INTO BEING OVER THE LAST
SEVERAL HOURS, THERE STILL REMAINS QUITE A BIT OF UNCERTAINTY
WHERE THE REMNANTS WILL TRACK. THE NAM AND GFS CONTINUE TO EXHIBIT
FAIRLY LARGE DISCREPANCIES IN TIMING AND LOCATION AND EVEN AMONGST
THE ENSEMBLES THERE'S A BIG DISPARITY. A MAJORITY OF THE SOLUTIONS
KEEP THE BULK OF THE STRONGEST ACTIVITY OFFSHORE OVER THE COASTAL
WATERS, AND MOVING NORTH TOWARDS THE BAY AREA, WHICH WOULD LIKELY
FAVOR THE WESTERN PORTION OF THE AREA AND NOT AS MUCH OVER LA
COUNTY. THE NAM IS QUITE A BIT FASTER WITH IT, SHOWING POSSIBLE
CONVECTION BEGINNING AS EARLY AS TUESDAY AFTERNOON ACROSS SOUTHERN
AREAS AND THE ADJACENT COASTAL WATERS. HOWEVER, MOST OF THE
ENSEMBLES SUGGEST EITHER LATE TUESDAY NIGHT OR WEDNESDAY FOR THE
ONSET OF ANY CONVECTIVE ACTIVITY SOUTH OF PT CONCEPTION AND LATER
WEDNESDAY INTO THURSDAY TO THE NORTH. THERE COULD BE A PERIOD OF
DRY LIGHTNING EARLY ON THE IN THE EVENT, BUT INCREASING PW'S
THEREAFTER WILL KEEP MOST OF THE STORMS ON THE WET SIDE. ALSO,
SHOWER AND THUNDERSTORM ACTIVITY COULD OCCUR DAY OR NIGHT AS THERE
IS AMPLE INSTABILITY ALOFT TO GENERATE STORMS EVEN WITHOUT THE
SUN'S HEAT. FLASH FLOOD POTENTIAL WILL BE INCREASING WITH TIME,
BUT THE BEST CHANCES FOR THAT WOULD LIKELY BE WED NIGHT INTO THU
WHEN THE DEEPEST MOISTURE ARRIVES.
LONG TERM (THU-SUN)
14/217 PM.
LATE WEDNESDAY NIGHT INTO THURSDAY COULD BE THE PERIOD OF
STRONGEST AND MOST WIDESPREAD STORM ACTIVITY BASED ON THE
LATEST ENSEMBLE SOLUTIONS. AS MENTIONED, THE CURRENT TRACK APPEARS
TO FAVOR THE WESTERN PORTION OF THE AREA MORE THAN THE EAST, BUT
CERTAINLY CAN'T RULE OUT STRONG STORMS WITH HEAVY RAIN AND
LIGHTNING ANYWHERE.
AFTER THE INITIAL SURGE OF MARIO MOISTURE MOVES THROUGH WEDNESDAY
AND THURSDAY, MODELS SHOW A SECOND MOISTURE SURGE COMING THROUGH
FRIDAY INTO SATURDAY, MAINTAINING SHOWER AND STORM CHANCES INTO
NEXT WEEKEND. SO THIS COULD BE A LENGTHY PERIOD OF SHOWERY WEATHER
WITH ON AND OFF THUNDERSTORMS WITH HEAVY RAIN AT TIMES AND GUSTY
WINDS.
IT WILL BE WARM AND MUGGY THROUGH NEXT WEEKEND, EVEN OVERNIGHT AS
WELL WITH CLOUDS AND MOISTURE TRAPPING A LOT OF THE WARMTH FROM
THE DAY. WIDESPREAD LOWS IN THE 70S ARE POSSIBLE THROUGH NEXT
WEEKEND. HIGHS EACH DAY WILL BE TRICKY AND LARGELY DEPENDENT UPON
WHERE THE CLOUDS AND SHOWERS DEVELOP BUT WILL GENERALLY RANGE
FROM THE UPPER 70S TO LOWER 90S. GIVEN THE HIGHER THAN NORMAL
HUMIDITIES, CAN'T RULE OUT THE POSSIBILITY OF ADDITIONAL HEAT
ADVISORIES THROUGH THE REST OF THE WEEK.
AVIATION
14/1734Z.
AT 1658Z AT KLAX, THE MARINE LAYER WAS 2600 FT DEEP. THE TOP OF
THE INVERSION WAS AT 4300 FT WITH A TEMPERATURE OF 21 C.
HIGH CONFIDENCE IN VFR TAFS FOR KPMD AND KWJF.
OVERALL, LOW TO MODERATE CONFIDENCE FOR COASTAL & VALLEY SITES.
TIMING OF CIG/VSBY RESTRICTIONS MAY BE OFF BY 3 HOURS & FLIGHT
CATEGORIES MAY BE OFF BY ONE CAT AT TIMES WHEN CIGS ARE PRESENT.
THERE IS A 30% CHANCE LIFR CIGS ARRIVE AT LEAST BRIEFLY AT KSBP
FROM 12Z TO 17Z SUNDAY. SIMILAR CHANCE THAT CLOUDS DO NOT ARRIVE
AT KPRB & KSMX. THERE IS A 20% CHANCE CLOUDS DO NOT ARRIVE AT KBUR
& KVNY.
KLAX...MODERATE CONFIDENCE IN 18Z TAF. ARRIVAL AND CLEARING TIMES
MAY BE OFF BY 2 HOURS. FLIGHT MINIMUMS MAY BE OFF BY ONE CATEGORY.
NO SIGNIFICANT EAST WIND COMPONENT EXPECTED THROUGH THE PERIOD.
KBUR...MODERATE CONFIDENCE IN 18Z TAF. ARRIVAL AND CLEARING TIMES
MAY BE OFF BY 2 HOURS. 15% CHANCE FOR LIFR CIGS FROM 10Z TO 15Z
MON. 20% CHANCE FOR NO LOW CLOUDS TONIGHT.
MARINE
14/115 PM.
SMALL CRAFT ADVISORY (SCA) LEVEL NW WINDS (20-30 KTS) WILL IMPACT
THE OUTER WATERS AND THE NEARSHORE WATERS ALONG THE CENTRAL COAST
THROUGH EARLY MONDAY MORNING, PEAKING IN THE AFTERNOON AND
EVENING HOURS. GALE FORCE WIND GUSTS (~35 KT) ARE LIKELY THIS
AFTERNOON AND EVENING OVER THE NORTHERN OUTER WATERS BEYOND 20 NM
FROM SHORE. STRONGEST ACROSS NORTHEAST PORTIONS OF PZZ670. GALE
FORCE WIND GUSTS ARE ALSO POSSIBLE ACROSS THE FAR NW PORTION OF
PZZ645 THIS EVENING (15% CHANCE). SEAS WILL PEAK 7-9 FEET ACROSS
THE NORTHERN WATERS TODAY INTO TONIGHT. CONDITIONS ARE EXPECTED TO
STAY BELOW ADVISORY LEVELS ON MONDAY AND TUESDAY. LOW TO MODERATE
CONFIDENCE IN WINDS INCREASING CLOSE TO SCA LEVELS WEDNESDAY
THROUGH FRIDAY.
FOR THE INNER WATERS SOUTH OF POINT CONCEPTION, CONDITIONS ARE
GENERALLY EXPECTED TO REMAIN SUB-ADVISORY THROUGH MONDAY. THERE IS
A 25% CHANCE FOR WNW WINDS 20-25 KTS ACROSS THE SOUTHERN CALIFORNIA
BIGHT IN THE AFTERNOON AND EVENING TUESDAY, INCREASING TO 50% CHANCE
WEDNESDAY.
SUB-TROPICAL MOISTURE WILL MOVE NORTHWARD INTO THE COASTAL WATERS
THIS WEEK, BRINGING CHANCES OF SHOWERS AND THUNDERSTORMS TO THE
AREA AS EARLY AS TUESDAY, WITH BETTER CHANCES WEDNESDAY THROUGH
AT LEAST FRIDAY.
LOX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 9 PM PDT THIS EVENING
FOR ZONE 645. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 PM PDT THIS AFTERNOON
FOR ZONE 670. (SEE LAXMWWLOX).
GALE WARNING IN EFFECT UNTIL 9 PM PDT THIS EVENING FOR ZONE
670. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT UNTIL 9 AM PDT MONDAY FOR ZONE
673. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT MONDAY FOR ZONE
676. (SEE LAXMWWLOX).
PUBLIC...MW
AVIATION...BLACK
MARINE...BLACK/LEWIS
SYNOPSIS...MW/HALL
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page