430  
FXUS66 KLOX 141656  
AFDLOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA  
956 AM PDT SUN SEP 14 2025  
   
SYNOPSIS  
14/943 AM.  
 
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-TUE)  
14/955 AM.  
 
***UPDATE***  
 
THE MARINE LAYER LOWERED TO AROUND 2500 FEET SOUTH OF PT  
CONCEPTION AND LOW CLOUDS ARE SOLID ACROSS THE COAST AND LOWER  
VALLEYS. LOOKING FOR A SLIGHTLY WARMER DAY FOR THE MOST PART BUT  
STILL SLIGHTLY BELOW NORMAL.  
 
ALONG THE CENTRAL COAST LOW CLOUDS WERE MUCH MORE SPARSE AS THE  
MARINE LAYER THERE LOWERED TO UNDER 1000 FEET BASED ON THE 12Z KVBG  
SOUNDING. THIS IS LIKELY IN RESPONSE TO THE TROUGH PASSAGE ACROSS  
OREGON WHICH GENERATED HIGHER SURFACE PRESSURES AND IN TURN  
INCREASING NORTH TO NORTHEAST WINDS IN THE LOWER LEVELS. WINDS  
ACROSS THE SANTA LUCIAS THIS MORNING WERE GUSTING TO 30+ MPH IN  
SOME AREAS AND THIS WILL PROVIDE A BOOST IN TEMPERATURES ALONG THE  
CENTRAL COAST WITH HIGHS CLOSE TO 90 IN THE SAN LUIS OBISPO AREA  
AND EVEN 70S TO LOWER 80S ALONG PARTS OF THE COASTAL SECTION.  
 
***FROM PREVIOUS DISCUSSION***  
 
THE LATEST WATER IMAGERY SHOWS FLAT RIDGING IN PLACE OVER THE  
REGION EARLY THIS MORNING. THE LOW CLOUD FIELD LOOKS A LITTLE MORE  
DISORGANIZED CURRENTLY, AND AS A RESULT, THERE IS LOWER  
CONFIDENCE IN THE LOW CLOUDS AND FOG FOR TODAY. AN UPPER-LEVEL  
RIDGE OF HIGH PRESSURE OVER NORTHERN MEXICO WILL BUILD  
NORTHWESTWARD INTO THE STATE THROUGH TUESDAY, THEN EXPAND ACROSS  
THE GREAT BASIN AND DESERT SOUTHWEST INTO LATE WEEK. A WARMING  
TREND WILL VERY LIKELY CONTINUE ACROSS THE AREA THROUGH WEDNESDAY  
AS 500 MB HEIGHTS WILL CLIMB A DECAMETER OR TWO EACH DAY.  
WEAKENING ONSHORE FLOW IS TAKING PLACE ACROSS THE REGION THIS  
MORNING, AND WITH LESS COVERAGE OF LOW CLOUDS AND FOG, A WARMER  
DAY IS ALREADY SHAPING UP FOR TODAY. AT THE SURFACE, SUB-ADVISORY  
SUNDOWNER AND SANTA LUCIA WINDS HAVE DEVELOPED OVERNIGHT. ALONG  
THE CENTRAL COAST, THE SANTA LUCIA WIND REGIME WILL SERVE TO ADD  
SOME COMPRESSIONAL HEATING TO THE WARMING TREND TODAY.  
 
CONFIDENCE IS HIGHER FOR THE BEST WARMING TAKING PLACE FOR MONDAY  
AND TUESDAY, BUT SOUTHEAST FLOW ALOFT DEVELOPING COULD BRING SOME  
MONSOONAL MOISTURE INTO THE REGION AS EARLY AS TUESDAY AFTERNOON.  
THE FLOW PATTERN COULD TAP INTO THE REMNANTS OF FORMER TROPICAL  
STORM MARIO AS MOVES WELL SOUTH OF THE REGION. THE LATEST  
DETERMINISTIC SOLUTIONS FAVOR THE SPREAD OF MOISTURE INTO THE  
REGION BETWEEN TUESDAY AND WEDNESDAY, BUT THE FORECAST ENSEMBLES  
LEAN TOWARD ANY PRECIPITATION HOLDING OFF UNTIL WEDNESDAY. THERE  
ARE A FEW SOLUTIONS WITH PRECIPITATION AS SOON AS TUESDAY. POPS  
FOR TUESDAY WERE BUMPED A LITTLE HIGHER OVER NBM VALUES WHILE  
EMPHASIZING THE HIGHER TERRAIN DURING THE AFTERNOON AND EVENING  
HOURS.  
   
LONG TERM (WED-SAT)  
14/356 AM.  
 
A MONSOONAL FLOW PATTERN LOOKS TO BE WEDGED IN ACROSS THE REGION  
BETWEEN WEDNESDAY AND THURSDAY, AND POSSIBLY INTO FRIDAY AND  
SATURDAY. A MORE HUMID AIR MASS IS LIKELY TO PUSH INTO THE  
REGION FOR MID-TO-LATE THIS WEEK, BUT LOW CONFIDENCE EXISTS IN  
THE ACTUAL COVERAGE OF SHOWERS AND THUNDERSTORMS, THE FORECAST FOR  
LOW CLOUDS AND FOG, AND THE WARMING TREND AFTER WEDNESDAY. WHILE A  
WARMING TREND IS ADVERTISED INTO WEDNESDAY, ANY CLOUDS THAT  
DEVELOP COULD CUT INTO DAYTIME TEMPERATURES. CONFIDENCE IS HIGHER  
FOR A WARM AND HUMID PATTERN DEVELOPING WITH LIMITED NIGHT THROUGH  
MORNING LOW CLOUDS AND FOG, BUT IT IS ENTIRELY POSSIBLE THAT  
WEDNESDAY AND PART OF THURSDAY COULD END UP COOLER UNDER A CLOUD  
SHIELD.  
 
EMBEDDED ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS COULD  
DEVELOP IN THIS PATTERN JUST ABOUT ANYWHERE, ESPECIALLY DURING  
THE AFTERNOON AND EVENING HOURS, BUT CONFIDENCE IS LOW ON THE  
ACTUAL PLACEMENT AT THIS TIME. ECMWF EFI VALUES HINT AT THE MOST  
ANOMALOUS CAPE VALUES OVER THE COASTAL WATERS AND INTO SANTA  
BARBARA AND SAN LUIS OBISPO COUNTIES WHILE ENS STANDARDIZED  
ANOMALIES ALSO ADVERTISE A SIMILAR PATTERN WITH THE MOISTURE  
PARAMETERS. THIS WOULD AGREE WITH DETERMINISTIC GFS SOLUTIONS IN  
HIGHLIGHTS THE BEST CHANCES OVER THE COASTAL WATERS AND INTO THE  
CENTRAL COAST OF CALIFORNIA, BUT THIS ALL IMPLIES THAT MODEL  
CONVECTIVE SCHEMES ARE WORKING AS ADVERTISED. WHILE THE PRESENCE  
OF A TROUGH CLIPPING THE AREA WILL LIKELY BE THE DRIVER OF THE  
SCENARIO, THIS FAR OUT, CONFIDENCE REMAINS LOW TO MODERATE.  
FUTURE SHIFTS WILL NEED TO WATCH THIS CLOSELY AS THERE COULD BE  
POTENTIAL IMPACTS FOR THE GIFFORD, MADRE, AND LAKE BURN SCARS. FOR  
NOW, THE FORECAST POPS START WITH NBM VALUES, BUT POPS LEAN  
HIGHER OVER MORE TYPICAL AREAS IN THE MOUNTAINS AND DESERT.  
 
AS WITH ANY OF THESE MONSOONAL MOISTURE SURGES, THERE IS A LOW  
CHANCE THAT A FLOOD WATCH COULD BE NEEDED FOR RECENT BURN SCARS.  
EPS PRECIPITABLE WATER VALUE MEANS APPROACH 1.50 INCHES, OR  
NEARING 99TH PERCENTILE FOR THE CFSR PERIOD FOR AT LEAST WEDNESDAY  
AND THURSDAY. ANY SHOWERS AND THUNDERSTORMS THAT DEVELOP DURING  
THIS PERIOD COULD CONTAIN BRIEF HEAVY DOWNPOURS, GUSTY AND ERRATIC  
WINDS, AND FREQUENT LIGHTNING. CURRENTLY, THE FLOW PATTERN SHOULD  
ALLOW FOR STORMS TO MOVE FAIRLY RAPIDLY, BUT FUTURE SHIFTS WILL  
NEED TO TAKE A CLOSER LOOK AT THE STEERING FLOW AND THE POTENTIAL  
FOR TRAINING STORMS OVER THE HIGHER TERRAIN.  
 
THERE IS A DECENT AMOUNT OF UNCERTAINTY FOR FRIDAY AND SATURDAY IN  
REGARDS TO HOW LONG THE MONSOONAL MOISTURE HANGS AROUND. WHILE  
GEFS SOLUTIONS OFFER UP MORE UNCERTAINTY, EPS SOLUTIONS HOLD ON TO  
PRECIPITABLE WATER VALUES NEAR THE 97TH PERCENTILE INTO LATE  
WEEK. AS A RESULT, THE FORECAST HANGS ONTO SLIGHT CHANCE POPS OVER  
THE MOUNTAINS AND DESERT INTO NEXT WEEKEND.  
 
 
   
AVIATION  
14/1123Z.  
 
AT 0708 AT KLAX, THE MARINE LAYER WAS 1700 FT DEEP. THE TOP OF  
THE INVERSION WAS AT 3200 FT WITH A TEMPERATURE OF 23 C.  
 
HIGH CONFIDENCE IN KPMD AND KWJF TAFS.  
 
LOW TO MODERATE CONFIDENCE IN ALL COASTAL AND VALLEY TAFS DUE TO  
PATCHY AND DISORGANIZED LOW CLOUDS. 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. CIGS MAY ALSO BOUNCE  
BETWEEN SCT AND BKN THROUGH AT LEAST 18Z. THERE IS A 50% CHANCE  
KSMX REMAINS VFR THROUGH THE PERIOD, AND A 20% CHANCE FOR LIFR TO  
IFR CIGS AT KSBP BETWEEN 14Z AND 17Z. THERE IS A CHANCE FOR LOW  
CLOUDS TO ARRIVE TONIGHT AT KSBP (15%), KSMX (30%) AFTER 03Z.  
 
KLAX...MODERATE CONFIDENCE IN TAF. CIGS MAY SCT AND REFORM DURING  
THE PERIOD. CLEARING TIMES MAY BE OFF +/- 2 HOURS, AND ARRIVAL  
TIMES MAY BE OFF +/- 3 HOURS. THERE IS A 30% CHANCE OF OVC007-009  
CIGS AFTER 00Z MON. NO SIGNIFICANT EAST WIND COMPONENT EXPECTED  
THROUGH THE PERIOD.  
 
KBUR...MODERATE CONFIDENCE IN TAF. CLEARING TIME MAY BE OFF BY  
+/- 90 MIN AND ARRIVAL TONIGHT MAY BE OFF +/- 3 HOURS. 15% CHANCE  
FOR LIFR CIGS AFTER 10Z MON. 20% CHANCE FOR NO LOW CLOUDS  
TONIGHT.  
 
 
   
MARINE  
14/806 AM.  
 
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 (34-38 KTS) ARE LIKELY THIS  
AFTERNOON AND EVENING OVER THE NORTHERN OUTER WATERS BEYOND 20 NM  
FROM SHORE. STRONGEST ACROSS NORTHEAST PORTIONS OF PZZ670. THERE  
IS A 20% CHANCE OF GALES NEARSHORE ALONG THE CENTRAL COAST TO 20  
NM OFF SHORE. 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% WEDNESDAY AND THURSDAY.  
 
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 FROM 3 PM THIS AFTERNOON TO 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/HALL  
AVIATION...LEWIS  
MARINE...LEWIS/BLACK  
SYNOPSIS...MW/HALL  
 
WEATHER.GOV/LOSANGELES  
 
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:  
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX  
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