085  
FXUS66 KLOX 201038 AAA  
AFDLOX  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA  
338 AM PDT TUE MAY 20 2025  
   
SYNOPSIS  
20/213 AM.  
 
A RIDGE OF HIGH PRESSURE WILL RESULT IN AN EXTENDED PERIOD OF  
HOT WEATHER THIS WEEK, PEAKING ON WEDNESDAY AND THURSDAY. HIGH  
TEMPERATURES WILL BE WELL ABOVE NORMAL. GUSTY WINDS ARE EXPECTED  
ACROSS SOUTHERN SANTA BARBARA COUNTY AND IN THE LOS ANGELES COUNTY  
MOUNTAINS NEAR THE GRAPEVINE.  
 
 
   
SHORT TERM (TDY-THU)  
20/308 AM.  
 
THREE VERY WARM DAYS ON TAP ESP AWAY FROM THE BEACHES. AT THE  
UPPER LEVELS A RIDGE WILL BUILD IN TODAY AND THEN PEAK TOMORROW.  
ON THURSDAY THE RIDGE WILL FLATTEN SOME AS A TROF ROLLS THROUGH  
THE PACNW. HGTS WILL REACH 584 DAM TODAY, 585 DAM WED AND THEN  
FALL TO ABOUT 582 DAM LATER THURSDAY. CURRENTLY THERE IS ABOUT A  
MB OF ONSHORE FLOW TO THE EAST AND A MB OF OFFSHORE FLOW FROM THE  
NORTH. JUST AFTER DAWN THE E/W GRADIENT WILL BE CLOSE TO ZERO  
WHILE THE OFFSHORE PUSH FROM THE N WILL REACH 2 MB. SIMILAR  
GRADIENTS ARE FCST FOR WED WITH WEAK ONSHORE TRENDS SLATED FOR  
THURSDAY.  
 
LOOK FOR 4 TO 8 DEGREES OF WARMING TODAY, FOLLOWED BY 1 TO 3  
DEGREES OF ADDITIONAL WARMING ON WEDNESDAY. TODAY'S TEMPS WILL  
COME IN JUST UNDER ADVISORY LEVELS, BUT PEOPLE WORKING OR PLAYING  
OUTSIDE IN THE VLYS TODAY SHOULD TAKE HEAT RELATED PRECAUTIONS.  
THE LOWS TONIGHT WILL BE ABOVE NORMAL IN MANY VLY LOCATIONS WHICH  
WILL EXACERBATE THE HEAT DANGER. THIS COMBINED WITH THE EXTRA  
WARMING WILL PUSH MANY LOCATIONS AWAY FORM THE NEARSHORE AREA INTO  
ADVISORY LEVELS - PLEASE SEE THE PRODUCT LAXNPWLOX FOR DETAILS  
AND PRECAUTIONS ABOUT THESE HEAT DANGERS. HIGHS WEDNESDAY WILL BE  
IN THE 70S AT THE BEACHES, THE 80S ACROSS THE INLAND COASTAL AREAS  
AND IN THE 90S FOR THE VLYS. THERE IS A 40 PERCENT CHC THAT THE  
WARMEST VLY LOCATIONS WILL END UP AT 100 OR 101 DEGREES. THESE MAX  
TEMPS ARE MOSTLY 12 TO 18 DEGREES ABOVE NORMAL.  
 
SOME SHALLOW MARINE LAYER CLOUDS ARE FORECAST TO DEVELOP UNDER THE  
LOW AND STRONG INVERSION THURSDAY MORNING AND LOW CLOUDS ARE  
LIKELY ACROSS THE LA/VTA COUNTY BEACHES. BECAUSE THE MARINE LAYER  
WILL BE SO SMOOSHED DENSE FOG WILL LIKELY ACCOMPANY THE CLOUDS.  
MAX TEMPS WILL COOL SOME ACROSS LA AND VTA COUNTIES BUT NOT  
ENOUGH TO END THE HEAT ADVISORIES. A STRONGER ONSHORE GRADIENT  
LATER IN THE AFTERNOON MAY BRING SOME LATE AFTERNOON COOLING  
RELIEF.  
   
LONG TERM (FRI-MON)  
20/1214 AM.  
 
EC AND THE GFS STILL IN GOOD AGREEMENT FOR THE FRI/SAT FORECAST. A  
SMALL TROF WILL PUSH THROUGH THE STATE ON FRIDAY AND HGTS WILL  
LOWER TO 580 DAM. ONSHORE FLOW TO THE EAST WILL INCREASE SLIGHTLY  
WHILE OFFSHORE FLOW FROM THE N WILL CONTINUE. MARINE LAYER  
STRATUS WILL LIKELY AFFECT MOST OF THE COASTS (SAVE FOR THE SBA  
SOUTH COAST) AND THE SANTA YNEZ VLY. THE LOWER HGTS AND SLIGHT  
LIFT FROM THE TROF WILL RAISE THE MARINE LAYER ENOUGH TO ALLOW  
SOME COOLER MARINE AIR INTO SOME OF THE VLYS. THIS COOLER AIR  
ALONG WITH THE STRONGER SEA BREEZE WILL COMBINE TO BRING 4 TO 8  
DEGREES OF COOLING TO THE CSTS AND VLYS. LOWERING HGTS WILL COOL  
THE INTERIOR A FEW DEGREES AS WELL.  
 
BIGGER COOLING IS ON TAP ON SATURDAY. THE ONSHORE PUSH TO THE EAST  
WILL NOT CHANGE MUCH BUT THE OFFSHORE FLOW FROM THE NORTH WILL  
SWITCH TO ONSHORE AND THIS WILL ENHANCE THE COOLING ACROSS THE  
CSTS/VLYS. COOLER AIR USHERED IN BEHIND FRIDAY'S TROF WILL COOL  
THE INTERIOR. THE CSTS WILL COOL 2 TO 4 DEGREES BUT THE VLYS WILL  
SEE 5 TO 10 DEGREES OF ADDITIONAL COOLING. WHILE THE MTNS AND  
INTERIOR COOL 3 TO 6 DEGREES. ALL OF THIS COOLING WILL BRING MAX  
TEMPS ACROSS THE CSTS/VLYS DOWN INTO THE 70S WITH JUST A FEW 80 OR  
81 DEGREE READINGS IN THE WARMEST VLY LOCATIONS. THESE MAX TEMPS  
ARE WITHIN A DEGREE OR 2 OF NORMAL.  
 
A LITTLE RIDGE POPS UP OVER THE AREA ON SUNDAY. THE MORNING LOW  
CLOUDS WILL LIKELY COVER THE LA CSTS AND THE CENTRAL COAST.  
PRESSURE GRADS ARE SIMILAR TO SATURDAY'S (AT LEAST IN THE MORNING)  
AND MAX TEMPS WILL BUMP UP A COUPLE OF DEGREES DUE TO HGTS RISES.  
THE AFTERNOON ONSHORE PUSH WILL INCREASE TO NEAR 9 MB TO THE EAST  
AND THIS WILL BRING GUSTY WINDS TO THE CENTRAL COAST AND THE  
WESTERN ANTELOPE VLY.  
 
THE RIDGE PUSHES OFF TO THE EAST ON MONDAY AS A LARGE EAST PAC  
TROF BEGINS TO APPROACH THE WEST COAST. MAX TEMPS WILL NOT CHANGE  
MUCH BUT THE STRONG ONSHORE FLOW TO THE EAST WILL CONTINUE AS WILL  
THE GUSTY AFTERNOON WINDS.  
 
 
   
AVIATION  
20/1036Z.  
 
AROUND 07Z, THE MARINE LAYER DEPTH WAS AROUND 900 FEET DEEP AT  
KLAX. THE TOP OF THE INVERSION WAS 1900 FEET WITH A TEMPERATURE  
OF 24 DEGREES CELSIUS.  
 
MODERATE CONFIDENCE EXISTS IN THE CURRENT FORECAST FOR COASTAL  
TERMINALS. HIGH CONFIDENCE EXISTS IN THE CURRENT FORECAST FOR  
VALLEY AND DESERT TERMINALS. THERE IS A MODERATE CHANCE OF IFR TO  
MVFR CONDITIONS AT COASTAL TERMINALS THROUGH 17Z, HIGHEST FOR  
CENTRAL COAST TERMINALS AND LOS ANGELES COUNTY COASTAL TERMINALS.  
 
KLAX...THERE IS A 30 PERCENT CHANCE OF IFR TO MVFR CONDITIONS KLAX  
THROUGH 16Z, AND AGAIN AFTER 08Z WEDNESDAY. OTHERWISE, VFR  
CONDITIONS ARE EXPECTED THROUGH THE PERIOD. ANY EASTERLY WINDS  
SHOULD REMAIN LESS THAN 7 KNOTS.  
 
KBUR...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. NO WIND  
IMPACTS ARE EXPECTED AT THIS TIME.  
 
 
   
MARINE  
20/326 AM.  
 
MODERATE TO HIGH CONFIDENCE IN THE CURRENT FORECAST. HIGHER  
CONFIDENCE EXISTS IN THE FORECAST FOR SEAS RELATIVE TO THE  
FORECAST FOR WINDS.  
 
FOR THE OUTER WATERS AND THE NEARSHORE WATERS ALONG THE CENTRAL  
COAST, CONDITIONS WILL BE AT LEAST SMALL CRAFT ADVISORY (SCA)  
LEVELS THROUGH WEDNESDAY NIGHT, EXCEPT FOR LULLS NEARSHORE ALONG  
THE CENTRAL COAST DURING LATE NIGHT AND EARLY MORNING HOURS.  
THERE IS A 60-90 PERCENT CHANCE FOR GALE FORCE WINDS LATE THIS  
AFTERNOON THROUGH LATE TONIGHT. THE HIGHEST CHANCES FOR GALE FORCE  
WINDS WILL BE FOR THE MAJORITY OF THE OUTER WATERS, WHILE THE  
LOWEST CHANCES WILL BE FOR THE NEARSHORE WATERS ALONG THE CENTRAL  
COAST AND THE FOR SOUTHERN OUTER WATERS. THERE IS A MODERATE CHANCE  
FOR GALE FORCE WINDS FOR THURSDAY AND FRIDAY.  
 
ACROSS THE SANTA BARBARA CHANNEL, THERE IS A 30-50 PERCENT CHANCE  
OF SCA CONDITIONS THIS AFTERNOON AND EVENING. LOCAL SCA WIND GUSTS  
ARE POSSIBLE ACROSS THE FAR WESTERN PORTION. THERE ARE LESSER  
CHANCES FOR LATE WEEK.  
 
SOUTH OF POINT MUGU, INTO THE SANTA MONICA BAY, AND THE SAN PEDRO  
CHANNEL, WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA LEVELS  
THROUGH AT LEAST FRIDAY.  
 
 
   
LOX WATCHES/WARNINGS/ADVISORIES  
 
CA...HEAT ADVISORY REMAINS IN EFFECT FROM 11 AM WEDNESDAY TO 9 PM  
PDT THURSDAY FOR ZONES  
88-343-348-351>353-356>358-368-374-375-548. (SEE LAXNPWLOX).  
HEAT ADVISORY REMAINS IN EFFECT FROM 11 AM THIS MORNING TO 9  
PM PDT THURSDAY FOR ZONES 369>373. (SEE LAXNPWLOX).  
PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT WEDNESDAY FOR  
ZONE 645. (SEE LAXMWWLOX).  
GALE WARNING IN EFFECT UNTIL 3 AM PDT WEDNESDAY FOR ZONES  
670-673-676. (SEE LAXMWWLOX).  
 
 
 
 
 
PUBLIC...RORKE  
AVIATION...HALL  
MARINE...HALL  
SYNOPSIS...KL/CILIBERTI  
 
WEATHER.GOV/LOSANGELES  
 
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:  
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX  
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