112
FXUS66 KLOX 290926
AFDLOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
226 AM PDT TUE JUL 29 2025
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
29/0544Z.
AT 0517Z AT KLAX, THE MARINE LAYER WAS AROUND 1300 FT DEEP. THE
TOP OF THE INVERSION WAS AROUND 2400 FEET WITH A MAX TEMPERATURE
OF 21 C.
HIGH CONFIDENCE IN VFR TAFS FOR KWJF AND KPMD.
MODERATE CONFIDENCE IN REMAINING TAFS. LOWER CONFIDENCE IN TIMING
OF FLIGHT CAT CHANGES, ESPECIALLY FOR KSBP, KSBA, KOXR, AND KCMA,
WHERE ARRIVAL OF CIGS TONIGHT/THIS MORNING MAY BE OFF +/- 2 HRS.
MINIMUM CIG HEIGHT MAY BE OFF +/- 200 FT. THERE IS A CHANCE FOR
NO LOW CLOUDS AT KSBP (30%), KSBA (30%), KOXR (15%), AND KCMA
(15%), KBUR (20%), AND KVNY (20%). AT KPRB, THERE IS A 20% CHANCE
FOR LIFR CIGS BETWEEN 12Z AND 16Z. PATCHY MARINE LAYER CLOUDS MAY
CAUSE CIGS TO FREQUENTLY VARY BETWEEN BKN AND SCT THROUGH AROUND
12Z.
KLAX...MODERATE CONFIDENCE IN TAF. CIGS MAY VARY FROM BKN TO SCT
THROUGH 12Z. 15% CHANCE FOR BRIEF CIGS 003-004 THROUGH 15Z.
TRANSITION TO VFR MAY BE ANYWHERE FROM 16Z TO 20Z. ARRIVAL OF CIGS
TONIGHT MAY BE OFF +/- 300 FT. NO SIGNIFICANT EAST WIND COMPONENT
EXPECTED.
KBUR...MODERATE CONFIDENCE IN TAF. ARRIVAL AND DEPARTURE OF CIGS
MAY BE OFF +/- 2 HOURS. MINIMUM CIG HEIGHT MAY BE OFF +/- 200 FT.
THERE IS A 20% CHANCE FOR NO LOW CLOUDS TONIGHT.
MARINE
29/147 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 WEDNESDAY AFTERNOON AND
EVENING AROUND PT DUME AND THROUGH THE SAN PEDRO CHANNEL,
OTHERWISE NO HAZARDOUS CONDITIONS EXPECTED FOR THE INNER WATERS OF
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...LEWIS
MARINE...LEWIS
SYNOPSIS...HALL
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
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