784
FXUS66 KLOX 200025
AFDLOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
425 PM PST SUN JAN 19 2025
SYNOPSIS
19/138 PM.
ANOTHER ROUND OF LOW CLOUDS IS EXPECTED TONIGHT, THEN SANTA ANA
WINDS WILL ARRIVE MONDAY MORNING AND CHASE THE LOW CLOUDS AWAY.
A MODERATE TO STRONG SANTA ANA WIND EVENT WILL AFFECT VENTURA AND
LOS ANGELES COUNTIES MONDAY NIGHT AND TUESDAY, WITH WEAKER
OFFSHORE FLOW CONTINUING FOR MUCH OF NEXT WEEK. TEMPERATURES WILL
BE BELOW NORMAL MONDAY AND TUESDAY, WITH A WARMING TREND LATER
NEXT WEEK. HUMIDITY WILL BE LOW TO VERY LOW MOST OF NEXT WEEK.
FROST OR FREEZING TEMPERATURES ARE POSSIBLE IN WIND SHELTERED
AREAS EACH NIGHT MONDAY THROUGH THURSDAY. THERE IS A DEVELOPING
CHANCE OF RAIN NEXT WEEKEND.
SHORT TERM (TDY-WED)
19/133 PM.
***HIGH WIND WARNINGS ARE IN EFFECT LATE MONDAY AFTERNOON THROUGH
TUESDAY MORNING FOR MOST OF VENTURA COUNTY AND LOS ANGELES COUNTY
DUE TO A HIGH LIKELIHOOD OF WIDESPREAD DAMAGING WINDS***
***DANGEROUS FIRE WEATHER CONDITIONS EXPECTED FOR MUCH OF VENTURA
AND LOS ANGELES COUNTIES LATE MONDAY MORNING THROUGH TUESDAY
EVENING POSSIBLY CONTINUING THROUGH THURSDAY***
A 2000 FT MARINE LAYER THAT BROUGHT EXTENSIVE LOW CLOUDS TO THE
CSTS/VLYS THIS MORNING REMAINS IN PLACE. ONSHORE FLOW TO THE EAST
HAS KEPT LOW CLOUDS PRESSED AGAINST THE BEACHES OF LA AND VTA
COUNTIES. LOW CLOUDS WILL ADVANCE AGAIN ACROSS MOST OF THE
CSTS/VLYS AS WELL AS THE PASO ROBLES AREA. AWAY FROM THE CLOUDS
A VERY DRY AND COOL AIR MASS WILL ALLOW FOR GOOD RADIATIONAL
COOLING UNDER CLEAR SKIES. MANY INTERIOR AREAS WILL AGAIN SEE
FREEZING TEMPERATURES. THERE WILL ALSO BE SOME NORTHERLY GUSTS
THROUGH THE FAVORED MTN PASSES BUT THEY WILL NOT REACH ADVISORY
LEVELS.
A MAJOR SHIFT IN THE WEATHER WILL OCCUR MONDAY MORNING. THE BASE
OF A VERY LONG WAVE (LAKE SUPERIOR TO LOS ANGELES) POS TILT TROF
WILL SWOOP THROUGH THE STATE. THIS WILL USHER BOTH GOOD COLD AIR
ADVECTION AND STRONG UPPER LEVEL NE WINDS. NE WINDS AT 850 MB
START OUT AT 35 KT BUT WILL ACCELERATE 50 KT AT NOON. 850 MB TEMPS
WILL DROP FROM 4 C TO -2 C THROUGH THE DAY. AT THE SAME TIME THERE
WILL BE A LARGE JUMP IN OFFSHORE FLOW WITH THE NAM SHOWING AN 7MB
INCREASE IN OFFSHORE FLOW UP TO 9 MB OFFSHORE (THE GFS IS LESS,
GOING FROM -2 TO -6)
NE WINDS WILL START IN THE MTNS A FEW HOURS BEFORE DAWN. DURING
THE MORNING HOURS AFTER SUNRISE THE WINDS WILL ACCELERATE AND MOVE
OUT OF THE MTNS INTO THE VLYS AND THEN THE COAST. GUSTS WILL
START INCREASE AND WILL REACH WARNING LEVELS DURING THE DAY. MAX
GUSTS ACROSS THE CSTS/VLYS WILL BE BETWEEN 55 AND 65 MPH AND THE
MTNS WILL SEE FREQUENT 60 TO 70 MPH GUSTS WITH LOCAL RIDGETOP
WINDS REACHING 70 TO 90 MPH. THESE WINDS WILL BE ORIENTED IN THE
TYPICAL NE SANTA ANA DIRECTION. THIS DIRECTION WILL BRING THE
GREATEST MTN WAVE POTENTIAL TO THE SAN FERNANDO AND SANTA CLARITA
VLYS.
THE WINDS WILL PEAK MONDAY EVENING AND OVERNIGHT AND WILL EXTEND
INTO TUESDAY MORNING BEFORE THE UPPER SUPPORT WANES AND THE SFC
GRADS BEGIN TO RELAX.
THESE STRONG WINDS WILL BRING HAZARDOUS WINDS AND WAVES TO
CATALINA ISLAND, AVALON HARBOR AS WELL AS THE CHANNEL ISLANDS. FOR
ALL OF THE DETAILS ON THE WINDS PLEASE SEE THE PRODUCT LAXNPWLOX.
LIKE MOST SANTA ANA'S MONDAY WILL SEE COOLING ACROSS THE INTERIOR
DUE TO COOL AIR ADVECTION WHILE THE COASTS AND VLYS SEE SOME
WARMING DUE TO THE THE COMPRESSIONAL WARMING. MOST AREAS TUESDAY
WILL SEE SOME WARMING SAVE FOR THE ANTELOPE VLY WHICH WILL COOL A
FEW MORE DEGREES.
OVERNIGHT LOWS IN THE WIND SHELTERED INLAND AREAS WILL BE VERY
COOL WITH MANY AREAS DIPPING BELOW FREEZING.
ON WEDNESDAY THE STATE WILL BE UNDER THE EAST SIDE OF A RIDGE WITH
581 HGTS OVER LA COUNTY. THERE WILL STILL BE 4 TO 6 MB OF OFFSHORE
FLOW FROM BOTH THE N AND E. THERE WILL BE NO UPPER SUPPORT BUT THE
GRADIENTS WILL LIKELY PRODUCE LOW END WIND ADVISORIES THROUGH THE
TYPICAL SANTA ANA WIND CORRIDOR. THE OFFSHORE FLOW AND HIGH
PRESSURE ALOFT WILL COMBINE TO BRING 6 TO 8 DEGREES OF WARMING TO
MOST AREAS. THESE WARM TEMPS AND OFFSHORE WINDS WILL BRING VERY
VERY DRY CONDITIONS AND CRITICAL FIRE WEATHER CONDITIONS TO MANY
AREAS.
****DUE TO THE STRONG WINDS AND VERY LOW RELATIVE HUMIDITY
VALUES, DANGEROUS HIGH END RED FLAG FIRE WEATHER CONDITIONS ARE
EXPECTED LATE MONDAY MORNING THROUGH TUESDAY EVENING. NEW OR
EXISTING FIRE IGNITIONS WILL HAVE A HIGH RISK FOR VERY RAPID FIRE
SPREAD AND EXTREME FIRE BEHAVIOR WITH LONG RANGE SPOTTING.
PLEASE REFER TO OUR FIRE WEATHER PRODUCTS (RFWLOX) AND THE FIRE
WEATHER DISCUSSION BELOW FOR ADDITIONAL DETAILS.****
LONG TERM (THU-SUN)
19/1227 PM.
THERE IS GOOD MODEL AGREEMENT WITH BOTH DETERMINISTIC AND
ENSEMBLES THROUGH FRIDAY.
ON WEDNESDAY THE STATE WILL BE UNDER THE EAST SIDE OF A RIDGE WITH
581 HGTS OVER LA COUNTY. THERE WILL STILL BE 4 TO 6 MB OF OFFSHORE
FLOW FROM BOTH THE N AND E. THERE WILL BE NO UPPER SUPPORT BUT THE
GRADIENTS WILL LIKELY PRODUCE LOW END WIND ADVISORIES THROUGH THE
TYPICAL SANTA ANA WIND CORRIDOR. THE OFFSHORE FLOW AND HIGH
PRESSURE ALOFT WILL COMBINE TO BRING 6 TO 8 DEGREES OF WARMING TO
MOST AREAS. THESE WARM TEMPS AND OFFSHORE WINDS WILL BRING VERY
VERY DRY CONDITIONS AND CRITICAL FIRE WEATHER CONDITIONS TO MANY
AREAS.
THURSDAY WILL BE LIKE A LESSER VERSION OF WEDNESDAY. OFFSHORE FLOW
WILL BE ABOUT HALF THAT OF WEDNESDAY. UPPER SUPPORT REMAINS
MINIMAL OR NON EXISTENT. THERE WILL BE MORNING CANYON WINDS BUT
THEY WILL BE UNDER ADVISORY LEVELS. MAX TEMPS WILL CLIMB ANOTHER 2
TO 4 LOCALLY 6 DEGREES AND MOST CST/VLY MAX TEMPS WILL BE IN THE
70S WITH AN ISOLATED 80 DEGREE READING NOT OUT OF THE QUESTION.,
THESE MAX TEMPS ARE 6 TO 12 DEGREES ABOVE NORMAL.
THE RIDGE BREAKS DOWN ON FRIDAY. THERE WILL BE ENOUGH OFFSHORE
FLOW IN THE MORNING TO KEEP THE LOW CLOUDS. THERE WILL BE A BIG
SWITCH TO ONSHORE FLOW IN THE AFTERNOON AND THIS WILL LEAD TO A
BIG 4 TO 8 DEGREE COOL DOWN.
THINGS START TO GET INTERESTING FOR THE WEEKEND. THERE IS NOT
GREAT MDL OR ENSEMBLE AGREEMENT SO EXACT CONFIDENCE IN LOW BUT THE
GENERAL 48 HOUR CONFIDENCE HAS GROWN QUITE A BIT. THERE WILL BE A
COMPACT UPPER LOW OFF THE COAST AND A COLD POS TILT RETROGRADING
TROF MOVING OUT OF THE GREAT BASIN AND INTO THE STATE. AT SOME
POINT THESE TWO FEATURES WILL MERGE INTO ONE UPPER LOW. THE EXACT
PHASING, TIMING AND LOCATION OF THIS SYSTEM IS STILL VERY MUCH UP
IN THE AIR.
LOOKING AT THE ENTIRE 48 HOUR PERIOD...THERE IS A 60 TO 70 PERCENT
CHC OF RAIN SOMETIME DURING THIS PERIOD. ABOUT 40 PERCENT OF THE
ENSEMBLES SHOW RAINFALL AMOUNTS OF OVER HALF AN INCH FOR MOST
COAST AND VLYS. THIS COULD ALSO BE A SIGNIFICANT MTN SNOW EVENT
WITH SNOW LEVELS AT OR EVEN UNDER 4000 FT. ONCE LAST DETAIL IS
THAT THE MOST LIKELY (40 PERCENT) SET UP WOULD ALLOW FOR AN
ENHANCED CONVECTIVE POTENTIAL WITH DIFLUENT FLOW ALOFT AND -25
DEGREE C 500MB. EARLY ESTIMATES CALL FOR A 25 PERCENT CHC OF A
TSTM DURING THIS PERIOD.
PLEASE NOTE THE OFFICIAL FORECAST IS DICED INTO 6 HOUR BLOCKS AND
THE CHANCE OF RAIN IN EACH 6 HOUR PERIOD IS MUCH LESS AND THE CHC
OF A TSTM IS BELOW 15 PERCENT IN ANY ONE PERIOD WHICH TO LOW TO
MENTION IN THE FORECAST.
THIS WEEKEND SYSTEM IS EVOLVING AND HOPEFULLY WILL BE REFINED OVER
THE NEXT FEW DAYS.
AVIATION
20/0024Z.
AT 0010Z AT KLAX, THE MARINE LAYER WAS 1700 FT DEEP. THE TOP OF
THE INVERSION WAS AT 4900 FT WITH A TEMP OF 10C.
MODERATE CONFIDENCE IN ALL TAFS EXCEPT FOR KPMD AND KWJF.
LOW CLOUDS EXPECTED TO FILL IN ACROSS MOST COASTAL/VALLEY AREAS
TONIGHT. CIG HGT COULD BE OFF BY +/- 300 FT. CLEARING TIMES
MONDAY MORNING COULD OCCUR 3 HOUR EARLIER THAN FCST.
KLAX...MODERATE CONFIDENCE IN TAF. THERE IS A 30 PERCENT CHC OF NO
CLEARING. THERE IS A 20 PERCENT CHC THAT LOW CLOUDS WILL CLEAR AT
14Z. GOOD CONFIDENCE THAT ANY EAST WIND COMPONENT REMAINS BELOW 8
KT THROUGH MONDAY, BUT 50 PERCENT CHANCE THAT IT COULD EXCEED 8
KNOTS BY MONDAY EVENING.
KBUR...MODERATE CONFIDENCE IN TAF. THERE IS A 30 PERCENT CHC THAT
LOW CLOUDS WILL ARRIVE AT 05Z. THERE IS 20 PERCENT CHC OF BKN008
CONDS 08Z-12Z. INCREASING NORTHEAST WINDS BY MONDAY LATE MORNING
INTO AFTERNOON. THERE IS A 20% CHANCE OF BRIEF GUSTS OF 35 TO 40
KNOTS BY LATE MONDAY AFTERNOON. LGT-MDT TURBC IS POSSIBLE AFT
16Z.
MARINE
19/224 PM.
FOR THE OUTER WATERS, SMALL CRAFT ADVISORY (SCA) LEVEL WINDS ARE
LIKELY (80-90% CHANCE) THRU MONDAY MORNING. THESE CONDITIONS WILL
BE FAVORED FROM POINT CONCEPTION TO SAN NICOLAS ISLAND WHICH
INCLUDES THE WATERS AROUND AND TO THE WEST OF THE CHANNEL ISLANDS
(PZZ676/673). THERE IS A 40-60% CHANCE OF GALE FORCE LEVEL NE
WINDS FOR THE WATERS AROUND AND TO THE SOUTH OF THE CHANNEL
ISLANDS (PZZ673 AND PZZ676) MONDAY THRU TUESDAY MORNING.
OTHERWISE, SUB-ADVISORY CONDS ARE EXPECTED THRU THURSDAY NIGHT.
FOR THE INNER WATERS NORTH OF PT SAL (PZZ645), THERE IS A 30%
CHANCE OF SCA LEVEL WIND GUSTS THIS AFTERNOON/EVE JUST OFFSHORE
OF PORT SAN LUIS AND SAM SIMEON POINT. OTHERWISE, SUB-ADVISORY
CONDS ARE EXPECTED THRU LATE IN THE WEEK.
FOR THE INNER WATERS SOUTH OF POINT CONCEPTION, THERE IS A 40-50%
CHANCE OF SCA LEVEL WIND GUSTS FOR FAR WESTERN PORTIONS OF THE
SANTA BARBARA CHANNEL SUNDAY AFTERNOON THRU LATE EVENING. FROM
VENTURA HARBOR TO SANTA MONICA AND OUT PAST THE CHANNEL ISLANDS,
THERE IS A 80-90% CHANCE OF GALE FORCE E/NE WIND GUSTS THROUGH
EARLY TUESDAY AFTERNOON. FOR THE NEARSHORE WATERS FROM CHANNEL
ISLANDS HARBOR TO MALIBU AND OUT TO SANTA CRUZ ISLAND, THERE IS A
40-50% CHANCE OF STORM FORCE WIND GUSTS MONDAY INTO TUESDAY
MORNING. FROM THE ORANGE COUNTY SHORES THROUGH THE SAN PEDRO
CHANNEL, THERE IS A 60-80% CHANCE OF GALE FORCE WIND GUSTS MONDAY
EVENING THROUGH TUESDAY MORNING. THERE IS A 70-80% CHANCE OF
25-30 KT WINDS IMPACTING AVALON HARBOR. STEEP, CHOPPY SEAS OF 5 TO
10 FEET WILL BE POSSIBLE DURING THIS TIME FRAME.
BREEZY OFFSHORE WINDS MAY CONTINUE AT TIMES FOR THE INNER WATERS
THROUGH THURSDAY OR FRIDAY.
FIRE WEATHER
19/136 PM.
STARTING LATER MONDAY MORNING AND CONTINUING THROUGH AT LEAST
THURSDAY, OFFSHORE FLOW AND VERY LOW HUMIDITIES WILL PREVAIL OVER
THE FORECAST AREA. THE STRONGEST WINDS FOR THE MONDAY/TUESDAY
TIMEFRAME ARE EXPECTED TO BE NOT ONLY OVER THE TYPICAL SANTA ANA
WIND CORRIDORS OF VENTURA AND LOS ANGELES COUNTIES, BUT ALSO
INCLUDE THE NORTHERN SAN GABRIEL VALLEY, THE PALOS VERDES HILLS,
THE CHANNEL ISLANDS AND CATALINA ISLAND. OTHERWISE, THE STRONGEST
WINDS WILL BE THROUGH THE USUAL SANTA ANA WIND CORRIDOR.
NORTHEAST WINDS ARE EXPECTED TO INCREASE SHARPLY BY MONDAY
AFTERNOON. THE PEAK OF THIS HIGH-END WIND EVENT WILL BE MONDAY
NIGHT INTO TUESDAY MORNING, WITH WIND GUSTS UP TO 60 TO 80 MPH
OVER THE L.A. COUNTY AND EASTERN VENTURA COUNTY MOUNTAINS, AND
GUSTS OF 55 TO 65 MPH POSSIBLE AT MANY VALLEY AND COASTAL AREAS OF
THESE TWO COUNTIES. LOCAL GUSTS UP TO 100 MPH PILL BE POSSIBLE IN
THE MOUNTAINS DURING THE PEAK OF THIS EVENT. WITH THE STRONG AND
DAMAGING WINDS AND HUMIDITIES LOWERING QUICKLY TO THE SINGLE
DIGITS AND TEENS, A PARTICULARLY DANGEROUS SITUATION (PDS) RED
FLAG WARNING IS IN EFFECT FOR MUCH OF VENTURA AND LOS ANGELES
COUNTIES FROM LATE MONDAY MORNING THROUGH EARLY TUESDAY AFTERNOON.
RED FLAG CONDITIONS ARE EXPECTED TO PERSIST FROM MID TUESDAY
AFTERNOON THROUGH TUESDAY EVENING FOR MANY OF THESE AREAS, WHEN A
NON-PDS RED FLAG WARNING CONTINUES.
THE STRONG AND GUSTY WINDS AND DRY AIR MASS ARE EXPECTED TO
SPREAD TO THE PALOS VERDES HILLS AND OFF THE COAST TO THE CHANNEL
ISLANDS AND CATALINA ISLAND AS WELL, AND A RED FLAG WARNING IS IN
EFFECT FOR THESE AREAS FROM MONDAY MORNING THROUGH EARLY TUESDAY
AFTERNOON.
GUSTY OFFSHORE WINDS AND WIDESPREAD VERY LOW HUMIDITIES WILL
CONTINUE LATER TUESDAY NIGHT THROUGH THURSDAY IN MUCH OF THESE
SAME AREAS. THE STRONGEST WINDS DURING THIS PERIOD ARE EXPECTED TO
BE WEDNESDAY NIGHT INTO THURSDAY MORNING WITH GUSTS IN THE 40 TO
55 MPH RANGE. MINIMUM HUMIDITES ARE FORECAST TO BE IN THE 3 TO 13
PERCENT RANGE OVERALL, WITH VERY POOR OVERNIGHT RECOVERIES. DUE TO
THE POTENTIAL FOR CONTINUED RED FLAG CONDITIONS, A FIRE WEATHER
WATCH IS ALSO IN EFFECT FOR MOST OF THESE AREAS FROM LATE TUESDAY
EVENING THROUGH THURSDAY EVENING.
IN ADDITION, THERE IS THE POTENTIAL FOR EAST TO SOUTHEAST WIND
GUSTS OF 20 TO 35 MPH TO OCCUR OVER INTERIOR SANTA BARBARA AND SAN
LUIS OBISPO COUNTIES AT TIMES THIS WEEK, WITH A 20 PERCENT CHANCE
OF RED FLAG CONDITIONS.
LOX WATCHES/WARNINGS/ADVISORIES
CA...HIGH SURF WARNING IN EFFECT FROM 8 AM MONDAY TO 2 PM PST
TUESDAY FOR ZONE 87. (SEE LAXCFWLOX).
COASTAL FLOOD ADVISORY IN EFFECT FROM 8 AM MONDAY TO 2 PM PST
TUESDAY FOR ZONE 87. (SEE LAXCFWLOX).
WIND ADVISORY REMAINS IN EFFECT FROM 8 AM MONDAY TO 2 PM PST
TUESDAY FOR ZONES 87-367-370-381>383-548. (SEE LAXNPWLOX).
HIGH WIND WARNING REMAINS IN EFFECT FROM 8 AM MONDAY TO 2 PM
PST TUESDAY FOR ZONES
88-354-355-358-362-369-371>380-549-550. (SEE LAXNPWLOX).
RED FLAG WARNING IN EFFECT FROM 8 AM MONDAY TO 10 PM PST
TUESDAY FOR ZONES 288-354-355-358-362-369-371>380-548. (SEE LAXRFWLOX).
FIRE WEATHER WATCH IN EFFECT FROM TUESDAY EVENING THROUGH
THURSDAY EVENING FOR ZONES 288-354-355-358-362-369>380. (SEE LAXRFWLOX).
RED FLAG WARNING IN EFFECT FROM 8 AM MONDAY TO 2 PM PST
TUESDAY FOR ZONES 367-370-381-382. (SEE LAXRFWLOX).
PZ...GALE WARNING IN EFFECT FROM 8 AM MONDAY TO 2 PM PST TUESDAY
FOR ZONES 650-655-676. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT UNTIL 8 AM PST MONDAY FOR
ZONES 673-676. (SEE LAXMWWLOX).
PUBLIC...DB/RORKE
AVIATION...GOMBERG
MARINE...SMITH/BLACK/RM
FIRE...SIRARD
SYNOPSIS...DB/RM/DMB
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
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