717
FXUS66 KLOX 291849
AFDLOX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1149 AM PDT TUE JUL 29 2025
UPDATED AVIATION DISCUSSION
SYNOPSIS
29/225 AM.
AN ONSHORE FLOW REGIME WILL KEEP A PERSISTENT MARINE LAYER DEPTH
IN PLACE. THE MARINE LAYER DEPTH WILL THIN SOME THROUGH MIDWEEK AS
AN UPPER-LEVEL RIDGE OVER THE SOUTHEAST BUILDS INTO THE FOUR
CORNERS REGION. MEANWHILE, AN UPPER-LEVEL TROUGH OF LOW PRESSURE
WILL SERVE TO KEEP ONSHORE FLOW IN PLACE AND NIGHT THROUGH MORNING
LOW CLOUDS AND FOG IN THE FORECAST FOR MOST COASTAL AND VALLEY
LOCATIONS. AWAY FROM THE COAST, A SLOW WARMING TREND WILL TAKE
SHAPE DUE TO THE INFLUENCE OF THE HIGH PRESSURE SYSTEM.
SHORT TERM (TDY-THU)
29/224 AM.
SOUTHWEST FLOW ALOFT CONTINUES ACROSS THE REGION THIS MORNING,
KEEPING AN ONSHORE FLOW REGIME AND A PERSISTENT MARINE LAYER DEPTH
IN PLACE. LOW CLOUDS AND FOG ARE A LESS-ENTRENCHED EARLY THIS
MORNING VERSUS THE LAST SEVERAL NIGHTS, BUT CLOUDS SHOULD RETURN
TO MOST COASTAL AREAS AND SOME VALLEY AREAS LATER THIS MORNING AS
MODERATE ONSHORE GRADIENTS CONTINUE ACROSS THE REGION. AN EDDY
CIRCULATION REMAINS INTACT ACROSS THE SOUTHERN CALIFORNIA BIGHT,
AND CLOUDS SHOULD FILL IN ACROSS THE BIGHT THROUGH DAYBREAK.
THE LATEST AMDAR SOUNDINGS FROM KLAX INDICATE A 1000 FOOT DEEP
MARINE LAYER DEPTH CURRENTLY, WHICH IS A LITTLE LOWER THAN WHAT
THE LATEST NAM BUFR TIME HEIGHT SECTIONS INDICATE. THE EDDY SHOULD
DEEPEN THE MARINE LAYER DEPTH TO AROUND 1500 FEET DEEP LATER THIS
MORNING, WHICH WOULD REPRESENT SOME THINNING OF THE MARINE LAYER
DEPTH. 1000-500 MB THICKNESS VALUES ARE STARTING TO CLIMB AND
CLAMP DOWN ON THE MARINE LAYER DEPTH AS AN UPPER-LEVEL RIDGE OVER
THE SOUTHEASTERN UNITED STATES EXPANDS AND BUILDS WEST INTO THE
FOUR CORNERS REGION. THE MARINE LAYER DEPTH WILL THIN THROUGH
THURSDAY AS SUBSIDING AIR ALOFT WITH THE HIGH PRESSURE SYSTEM
PRESSES DOWN ON TOP OF THE MARINE LAYER. AWAY FROM THE COAST AND
INTO THE VALLEYS, MOUNTAINS, AND DESERT, A SLOW AND GRADUAL
WARMING TREND WILL DEVELOP, BUT CLOSER TO THE COAST, TEMPERATURE
TRENDS WILL BE MUCH MORE MUTED AS THE HIGH PRESSURE SYSTEM WILL
SERVE TO SHARPEN AND STRENGTH THE MARINE INVERSION. ALONG THE
CENTRAL COAST, CLOUDS WILL STRUGGLE TO CLEAR EACH DAY, LIKELY
SHROUDING PORTIONS OF THE CENTRAL COAST IN CLOUDS THROUGH MUCH OF
THE WEEK AS EPS CLOUD COVER MEANS SUGGEST. THIS WILL KEEP
TEMPERATURES TRENDS NEAR PERSISTENT FOR THE COASTAL SECTIONS AND
COASTAL VALLEYS. STRONG ONSHORE FLOW SHOULD PERSIST FOR CENTRAL
CALIFORNIA AS A WEAK UPPER-LEVEL TROUGH REMAINS OVER THE CENTRAL
COAST AND TO THE NORTHWEST.
A COOLER AIR MASS TO THE NORTHWEST WILL KEEP HIGHER PRESSURE AT
THE SURFACE OVER THE NORTHEASTERN PACIFIC, WHILE A THERMAL LOW
PRESSURE SYSTEM WILL CONTINUE ACROSS SOUTHEASTERN CALIFORNIA. THIS
WILL SET UP A TIGHTER NORTHWEST SURFACE GRADIENT ACROSS THE AREA.
GUSTY SUNDOWNER WINDS WILL DEVELOP EACH NIGHT THROUGH WEDNESDAY
NIGHT AS KSBA-KSMX SURFACE PRESSURE GRADIENTS TIGHTEN. IF
TRAVELING ACROSS SOUTHERN SANTA BARBARA COUNTY THE NEXT SEVERAL
EVENINGS, WATCH OUT FOR GUSTY CROSS WINDS, ESPECIALLY WEST OF
GOLETA OUT TOWARD GAVIOTA. GUSTY NORTHWEST WINDS, WHICH COULD
DEVELOP RAPIDLY, SHOULD BE EXPECTED AT REFUGIO AND GAVIOTA STATE
BEACHES EACH EVENING. IF PLANNING OUTDOOR ACTIVITIES, IT MAY BE
BEST TO SCHEDULE THESE OUTSIDE THE WINDY TIMES.
LONG TERM (FRI-MON)
29/224 AM.
THE LATEST FORECAST ENSEMBLES INDICATE 500 MB HEIGHTS CLIMBING
BETWEEN THURSDAY AND THE WEEKEND. INTERIOR PORTIONS OF THE AREA
WILL SEE TEMPERATURES CLIMB ABOVE NORMAL FOR LATE WEEK AS THE HIGH
PRESSURE SYSTEM BUILDS INTO THE FOUR CORNERS REGION THROUGH THE
WEEK, AND THEN BUILD WEST INTO THE DESERT SOUTHWEST ON FRIDAY.
WHILE MOST OF THE WARMING WILL TAKE PLACE OUTSIDE OF THE MARINE,
SOUTHWEST FLOW ALOFT WILL REMAIN IN PLACE AND KEEP SOME MARINE
INFLUENCE IN THE FORECAST. CLUSTER ANALYSIS OF THE 500 MB PATTERN
SUGGESTS THE PERSISTENT TROUGH OVER THE NORTHEASTERN PACIFIC
OCEAN REMAINING ANCHORED IN PLACE THROUGH AT LEAST THE WEEKEND,
AND NIGHT THROUGH MORNING LOW CLOUDS AND FOG SHOULD PERSIST.
CLUSTER ANALYSIS DOES HINT AT A PATTERN SHIFT FOR EARLY NEXT WEEK
AS CLUSTERS 1 AND 3 WOULD SHIFT THE HIGH PRESSURE SYSTEM FARTHER
TO THE NORTH AND WEST. THIS WOULD PRODUCE MUCH HOTTER SOLUTIONS
ACROSS THE REGION. THE PATTERN, IF IT DEVELOPS, COULD CONFINE LOW
CLOUDS AND FOG TO THE COAST AND HEAT UP THE VALLEYS. IN PARTICULAR,
CLUSTER 3 COULD OPEN UP THE WINDOW FOR MONSOONAL FLOW TO WORK ITS
WAY INTO SOUTHERN CALIFORNIA. FOR NOW, THE LONG TERM PERIOD
FORECAST GOES WITH NBM VALUES.
AVIATION
29/1847Z.
AT 1808Z AT KLAX, THE MARINE LAYER WAS AROUND 700 FT DEEP. THE
TOP OF THE INVERSION WAS AROUND 3900 FEET WITH A MAX TEMPERATURE
OF 23 C.
HIGH CONFIDENCE IN VFR TAFS FOR KWJF AND KPMD.
HIGH CONFIDENCE IN TAF FOR KPRB, HOWEVER THERE IS A 10% CHANCE
FOR LIFR TO IFR CIGS AFTER 08Z.
MODERATE CONFIDENCE IN KBUR AND KVNY TAFS WHERE THERE IS A 20%
CHANCE OF IFR CONDS AFTER 06Z.
MODERATE CONFIDENCE IN REMAINING TAFS THROUGH 02Z, THEN LOW
CONFIDENCE. LOW CONFIDENCE IN ARRIVAL TIMES OF CIGS TONIGHT (+/-
3 HRS), HIGHEST UNCERTAINTY SOUTH OF POINT CONCEPTION. MINIMUM CIG
HEIGHT MAY BE OFF +/- 300 FT. THERE IS A 20% CHANCE FOR NO LOW
CLOUDS TONIGHT AT KLAX, KSMO, KLGB, AND A 30% CHANCE FOR LOW
CLOUDS TONIGHT (AFTER 06Z) AT KOXR AND KCMA. THERE IS A 30% CHANCE
OF LIFR-IFR CONDS AT KSBA AFTER 06Z.
KLAX...MODERATE CONFIDENCE IN TAF THROUGH 02Z, THEN LOW CONFIDENCE.
ARRIVAL OF CIGS TONIGHT MAY BE AS EARLY AS 02Z OR AS LATE AS 10Z.
CIG HEIGHTS MAY BE OFF BY +/- 300 FT. THERE IS A 30% CHANCE OF NO
LOW CLOUDS AFTER 00Z THROUGH 18Z WED. MODERATE CONFIDENCE IN ANY
EAST WIND COMPONENT REMAINING BELOW 7 KTS.
KBUR...HIGH CONFIDENCE IN TAF. THERE IS A 20% CHANCE OF BKN005-008
CONDS AFTER 06Z.
MARINE
29/703 AM.
HIGH CONFIDENCE IN SMALL CRAFT ADVISORY (SCA) WINDS ACROSS THE
OUTER WATERS THROUGH THE WEEKEND, WITH BRIEF LULLS POSSIBLE IN THE
MORNING HOURS. THERE IS A LOW CHANCE (15%) OF GALES AROUND POINT
CONCEPTION AND SOUTH TO SAN NICOLAS ISLAND WEDNESDAY EVENING. SEAS
ARE LIKELY TO BUILD TO 6 TO 8 FEET ACROSS THE OUTER WATERS
TONIGHT AND LAST THROUGH THE WEEK, THEN BUILDING TO 8 TO 10 FEET
THIS WEEKEND.
FOR THE NEARSHORE WATERS NORTH OF PT SAL, MODERATE TO HIGH
CONFIDENCE IN SCA LEVEL WINDS DURING THE AFTERNOON AND EVENING
HOURS EACH DAY THROUGH THE WEEKEND.
HIGH CONFIDENCE IN SCA LEVEL WINDS ACROSS THE WESTERN PORTION OF
THE SANTA BARBARA CHANNEL EACH AFTERNOON AND EVENING THROUGH
THURSDAY, WITH LOWER CHANCES FRIDAY. LOW TO MODERATE CHANCES THAT
SCA WINDS REACH EASTERN PORTIONS OF THE CHANNEL THROUGH THURSDAY
(MOST LIKELY WEDNESDAY).
LOCAL SCA LEVEL WIND GUSTS ARE POSSIBLE DURING THE AFTERNOON AND
EVENING HOURS TODAY AND WEDNESDAY AROUND PT DUME AND THROUGH THE
SAN PEDRO CHANNEL, OTHERWISE NO HAZARDOUS CONDITIONS EXPECTED FOR
THE INNER WATERS ALONG THE LOS ANGELES AND ORANGE COUNTY COASTS.
LOX WATCHES/WARNINGS/ADVISORIES
CA...WIND ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO 3 AM PDT
WEDNESDAY FOR ZONES 349-351. (SEE LAXNPWLOX).
PZ...SMALL CRAFT ADVISORY IN EFFECT FROM 3 PM THIS AFTERNOON TO 9
PM PDT THIS EVENING FOR ZONES 645-650. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT THURSDAY FOR
ZONES 670-673-676. (SEE LAXMWWLOX).
PUBLIC...HALL
AVIATION...LUND
MARINE...LEWIS/LUND
SYNOPSIS...HALL
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
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