835
FXUS66 KLOX 202130
AFDLOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
230 PM PDT SUN SEP 20 2026
SYNOPSIS
20/157 PM.
A WEAK UPPER LEVEL TROUGH WILL MOVE OVER THE AREA TODAY INTO
MONDAY, COOLING TEMPERATURES SLIGHTLY AND INCREASING MARINE LAYER
STRATUS. A WARMING TREND WILL BEGIN TUESDAY AND PEAK ON THURSDAY,
WITH HIGHS 5 TO 10 DEGREES ABOVE NORMAL.
SHORT TERM (TDY-WED)
20/220 PM.
AN UPPER LOW IS JUST WEST OF THE CENTRAL COAST THIS AFTERNOON. THE
LOW IS SPREADING LOTS OF HIGH CLOUDS ACROSS THE AREA TODAY BUT THE
LACK OF MOISTURE BELOW 15000 FEET IS PREVENTING ANY PRECIP FROM
DEVELOPING. CAN'T COMPLETELY RULE OUT A STRAY DROP OR TWO AT
HIGHER ELEVATIONS BUT OTHERWISE DRY CONDITIONS ARE EXPECTED
THROUGH AT LEAST TONIGHT. WITH THE HIGH CLOUDS DECREASING THROUGH
THE NIGHT AND LESS TRAPPED HEAT OVERNIGHT LOWS WILL LIKELY BE A
LITTLE COOLER.
AS THE LOW MOVES OVERHEAT TONIGHT, MODELS HAVE BEEN CONSISTENT
INDICATING A RAPIDLY DEVELOPING MARINE LAYER, POSSIBLY DEEPENING
TO 4000 FEET OR HIGHER BY MONDAY MORNING. GIVEN THE RAPID INCREASE
THERE'S GOOD CHANCE THAT SOME DRIZZLE WILL DEVELOP, ESPECIALLY IN
THE SOUTH FACING FOOTHILLS OF LA COUNTY. SOME LIGHT MEASURABLE
RAIN IS POSSIBLE IN THE MOST FAVORED AREAS, NAMELY FROM THE
EASTERN SAN FERNANDO VALLEY INTO THE SAN GABRIEL VALLEY AND
ADJACENT FOOTHILLS.
SIGNIFICANT COOLING WILL ACCOMPANY THE DEEPENING MARINE LAYER
MONDAY WITH THE WARMEST VALLEYS BARELY REACHING 80 AND DESERT
AREAS ONLY IN THE LOW 80S, ROUGHLY 10 DEGREES BELOW NORMAL. SKIES
ARE EXPECTED TO CLEAR EVENTUALLY MONDAY BUT IT MAY BE A REVERSE
CLEARING DAY WHERE COASTAL AREAS CLEAR BEFORE THE VALLEYS.
A WARMING TREND WILL BEGIN TUESDAY AND CONTINUE THROUGH AT LEAST
WEDNESDAY, BY WHICH TIME MOST AREAS WILL BE 4-8 DEGREES ABOVE
NORMAL. DOWNTOWN LA STILL HAS ABOUT A 40-50 PERCENT CHANCE OF
REACHING 90 WEDNESDAY WHILE THE WARMER VALLEYS HAVE A SIMILAR
CHANCE OF REACHING 100. CHANCES FOR HEAT ADVISORIES IN THOSE AREAS
REMAINS AROUND 30%
LONG TERM (THU-SUN)
20/229 PM.
UNCERTAINTY REMAINS WITH REGARD TO THE LENGTH OF THE NEXT HEAT
WAVE BUT THERE ARE STILL AT LEAST 30% OF THE SOLUTIONS SHOWING
LITTLE TO NO CHANGE IN HIGH TEMPERATURES THROUGH AT LEAST
SATURDAY. HOWEVER, MORE OF THE GUIDANCE PRODUCTS SUGGEST A SLOW
COOLING TREND AFTER WEDNESDAY DUE TO A SLOWLY DEEPENING TROUGH
ALONG THE WEST COAST.
AVIATION
20/2007Z.
AT 2000Z AT KLAX, THE MARINE LAYER WAS 2700 FT DEEP. THE TOP OF
THE INVERSION WAS AT 4000 FT WITH A TEMPERATURE OF 21 C.
HIGH CONFIDENCE IN VFR CONDS FOR KPMD & KWJF.
LOW TO MODERATE CONFIDENCE IN THE REMAINING SITES. THE TIMING OF
CIG AND ANY VSBY RESTRICTIONS MAY BE OFF 3 HRS AND FLIGHT
MINIMUMS BY ONE CATEGORY. HIGH CLOUDS MAY DISTURB THE MARINE LAYER
AND SITES WITH CIGS MAY BOUNCE BETWEEN CATEGORIES AT TIMES. THERE
IS A 5-10 PERCENT CHANCE OF -DZ/-SHRA FOCUSED THROUGH 18Z. THERE
IS A 20-30 PERCENT CHANCE THAT VFR CONDS PREVAIL.
KLAX...LOW TO MODERATE CONFIDENCE IN TAF. FLIGHT CAT CHANGES MAY
BE OFF BY 3 HOURS. ANY EAST WIND COMPONENT IS EXPECTED REMAIN
LESS THAN 6KT.
KBUR...LOW TO MODERATE CONFIDENCE CONFIDENCE IN TAF. FLIGHT CAT
CHANGES MAY BE OFF BY 3 HRS.
MARINE
20/110 PM.
FOR THE OUTER WATERS, MODERATE CONFIDENCE IN THE CURRENT
FORECAST. SMALL CRAFT ADVISORY (SCA) LEVEL WINDS ARE LIKELY (50-80
PERCENT CHANCE) FOR THE WATERS MAINLY WEST AND NORTHWEST OF POINT
CONCEPTION THROUGH TONIGHT OR MONDAY NIGHT. THE SCA WINDS WILL BE
MOST PERSISTENT AROUND POINT CONCEPTION. THERE IS A 40-50% CHANCE
OF SCA WIND GUSTS WEST AND SOUTH OF POINT CONCEPTION TUESDAY
AFTERNOON AND NIGHT AS WELL, OTHERWISE CONDS WILL BE BELOW SCA
LEVELS TUESDAY THROUGH THURSDAY NIGHT. EXPECT STEEP, CHOPPY SEAS
WITH THE SCA CONDITIONS.
FOR THE INNER WATERS N OF POINT SAL, MODERATE CONFIDENCE IN THE
CURRENT FORECAST. SCA WIND GUSTS ARE LIKELY (50-60 PERCENT CHANCE)
DURING THIS AFTERNOON AND EVENING, AND AGAIN TUESDAY. CONDS ARE
OTHERWISE EXPECTED TO BE BELOW SCA LEVELS MONDAY THROUGH THURSDAY.
FOR THE INNER WATERS S OF POINT CONCEPTION, MODERATE TO HIGH
CONFIDENCE IN THE CURRENT FORECAST. CONDS ARE EXPECTED TO BE BELOW
SCA LEVELS FOR THE MOST PART THROUGH THURSDAY NIGHT. HOWEVER, FOR
THE WESTERN SANTA BARBARA CHANNEL, THERE IS A 40%-50% CHANCE
MONDAY AFTERNOON/EVENING AND TUESDAY AFTERNOON/EVENING.
LOX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT MONDAY FOR
ZONES 645-670. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT UNTIL 5 AM PDT TUESDAY FOR
ZONE 673. (SEE LAXMWWLOX).
PUBLIC...MW
AVIATION...RM
MARINE...CILIBERTI/RS/RM
SYNOPSIS...MW
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
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