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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