Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 010541 AAA
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1040 PM PDT TUE SEP 30 2014

...UPDATED AVIATION DISCUSSION...

.SYNOPSIS...

A WARMING TREND IS EXPECTED INTO THE WEEKEND AS SURFACE HIGH
PRESSURE BUILDS INTO THE GREAT BASIN AND OFFSHORE FLOW STRENGTHENS
THROUGH THURSDAY MORNING. WEAKER OFFSHORE FLOW IS EXPECTED FOR THE
WEEKEND...BUT HOT AND DRY WEATHER WILL CONTINUE AS HIGH PRESSURE
BUILDS ALOFT. COOLER WEATHER IS POSSIBLE BY EARLY NEXT WEEK.

&&

.UPDATE...
OVERALL...VERY QUIET EVENING ACROSS SOUTHWESTERN CALIFORNIA. LATEST
AMDAR SOUNDINGS INDICATE MARINE INVERSION BASED NEAR 700 FEET.
SATELLITE/SURFACE OBS SHOW ONLY SOME PATCHY STRATUS/FOG CURRENTLY
ACROSS THE CENTRAL COAST (MAINLY VANDENBERG/LOMPOC AREA)...WITH
CLEAR SKIES ELSEWHERE. OVERNIGHT...MODELS STILL INDICATE AN EDDY
SPINNING UP WHICH COULD PUSH SOME LOW CLOUDS INTO THE COASTAL PLAIN
OF LOS ANGELES AND VENTURA COUNTIES. CONFIDENCE IN THIS SCENARIO
PLAYING OUT IS MODERATE AT BEST...BUT WILL NOT TOUCH THE FORECAST
FOR NOW.

OTHERWISE...THERE ARE SOME LOCALLY GUSTY NORTHWEST/NORTH WINDS
ACROSS SOUTHERN SANTA BARBARA COUNTY. HOWEVER...THESE WINDS ARE
ANTICIPATED TO REMAIN BELOW ADVISORY LEVELS THIS EVENING...BEFORE
DIMINISHING OVERNIGHT.

DID ISSUE A ZONE UPDATE EARLIER TO TWEAK SOME WIND AND CLOUD WORDING
FOR THE FIRST PERIOD. OTHERWISE...NO SIGNIFICANT CHANGES.

*** FROM PREVIOUS DISCUSSION ***

SHORT TERM (TONIGHT-THU)...
AFTERNOON TEMPERATURES ARE ALREADY QUITE A FEW DEGREES WARMER THAN
YESTERDAY IN MANY AREAS.  THE AFTERNOON HIGH TEMPERATURE FORECAST
FOR TODAY AND TOMORROW WAS BUMPED UP A BIT... ESPECIALLY IN THE LOS
ANGELES BASIN AND IN THE SAN FERNANDO AND SAN GABRIEL VALLEYS.  THIS
COULD RESULT IN TEMPERATURES RISING A BIT HIGHER THAN EXPECTED
OVERALL BUT MORE LIKELY IT INDICATES THAT THE WIND SHIFT WILL SET UP
SOONER.  THIS WOULD EFFECTIVELY WIPE OUT STRATUS ALONG THE COAST.

THE CURRENT FORECAST PACKAGE CONTINUES TO BE ON TRACK SO JUST A FEW
NUDGES AND TWEAKS WERE APPLIED IN ADDITION TO THE INCREASED
TEMPERATURES.  GUIDANCE MAINTAINS SATURDAY AS THE DAY WITH THE
HIGHEST AFTERNOON TEMPERATURES BUT LITTLE COOLING IS EXPECTED ON
SUNDAY AND MONDAY SO THE PEAK HEAT COULD EASILY SHIFT FURTHER
OUT.

THERE ALSO CONTINUES TO BE UNCERTAINLY AS TO WHAT COMES NEXT ONCE
THIS COMING HEAT EVENT CONCLUDES.  THERE IS SOME INDICATION THAT
ANOTHER ROUND OF HOT TEMPERATURES WILL DEVELOP CLOSELY ON THE HEELS
OF THIS EVENT AND IN TIME FOR A SECOND WEEKEND IN A ROW.  THE OTHER
SOLUTION BRINGS IN COOLER TEMPERATURES BUT LIKELY SOMEWHERE NEAR
NORMAL FOR MOST LOCATIONS.  THIS DICHOTOMY IN THE GUIDANCE HAS
EXISTED FOR A FEW DAYS NOW BUT THE RESOLUTION SHOULD COME SOONER
RATHER THAN LATER.

.LONG TERM (FRI-MON)...
AS MENTIONED... THE PEAK OF THE HEAT IS EXPECTED ON SATURDAY WITH
SLIGHT COOLING ON SUNDAY AND MONDAY THOUGH THERE IS A REASONABLE
CHANCE THAT TEMPERATURES COULD REMAIN HOTTER LONGER.  WINDS WILL
REMAIN OFFSHORE FOR MOST OF THE LONG TERM FORECAST PERIOD SO THE
MARINE PUSH MAY BE SLOW TO RETURN BUT THIS WILL NOT BE A STRONG
OFFSHORE EVENT SO THERE MAY BE LOCAL DEVELOPMENT ESPECIALLY ALONG
THE CENTRAL COAST.

&&

.AVIATION...01/0540Z...

MARINE LAYER AT KLAX AT 0325Z WAS 700 FEET DEEP AND THE INVERSION
TOP WAS 2100 FEET WITH A TEMPERATURE OF 24 DEGREES C.

OVERALL...MODERATE CONFIDENCE IN 06Z TAF PACKAGE. HIGH CONFIDENCE IN
VFR CONDS FOR ALL SITES THROUGH THIS EVENING. OVERNIGHT...HIGH
CONFIDENCE IN RETURN OF LIFR/VLIFR CONDS TO KSMX...BUT LOW
CONFIDENCE IN RETURN OF IFR/LIFR CONDS TO KLAX/KLGB.

KLAX...OVERALL...MODERATE CONFIDENCE IN 06Z TAF. HIGH CONFIDENCE IN
VFR CONDS THRU THIS EVENING. OVERNIGHT...LOW CONFIDENCE IN FORECAST
RETURN OF IFR/LIFR CONDS BETWEEN 11Z AND 16Z.

KBUR...OVERALL...HIGH CONFIDENCE IN 06Z TAF.

&&

.MARINE...30/800 PM...

ACROSS THE OUTER WATERS...HIGH CONFIDENCE IN SMALL CRAFT
ADVISORY-LEVEL WINDS CONTINUING THROUGH TONIGHT. FOR WEDNESDAY
THROUGH THE WEEKEND...WINDS ARE ANTICIPATED TO REMAIN BELOW ADVISORY
LEVELS.

FOR THE INNER WATERS...HIGH CONFIDENCE IN WINDS REMAINING BELOW
ADVISORY LEVELS THROUGH WEDNESDAY EVENING. BY LATE WEDNESDAY NIGHT
AND THURSDAY...HIGH CONFIDENCE IN WEAK TO MODERATE NORTHEAST WINDS
WITH WINDS POSSIBLY REACHING ADVISORY LEVELS LATE WEDNESDAY NIGHT
THROUGH EARLY THURSDAY AFTERNOON (ESPECIALLY NEAR SHORE) FROM
VENTURA TO MALIBU AND OUT TO THE ISLAND. FOR FRIDAY THROUGH THE
WEEKEND...WEAK OFFSHORE FLOW CAN BE EXPECTED AT NIGHT...AND WEAK
ONSHORE FLOW IN THE AFTERNOON/EVENING HOURS.

A LONG PERIOD SOUTH-SOUTHWEST SWELL IS ANTICIPATED TO ARRIVE ON
WEDNESDAY AND CONTINUE THROUGH FRIDAY.

&&

.FIRE WEATHER...CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TO
DEVELOP ACROSS MUCH OF VENTURA AND LOS ANGELES COUNTIES WEDNESDAY
NIGHT AS OFFSHORE GRADIENTS INCREASE AND HUMIDITIES FALL. NORTHEAST
WINDS WILL ACTUALLY BEGIN AS EARLY AS WEDNESDAY MORNING ACROSS THE
MOUNTAINS VALLEYS, HOWEVER HUMIDITIES ARE EXPECTED TO REMAIN ABOVE
20 PERCENT IN MOST AREAS UNTIL WEDNESDAY NIGHT WHEN MUCH DRIER AIR
MOVES IN. THE STRONGEST WINDS ARE EXPECTED WEDNESDAY NIGHT THROUGH
EARLY AFTERNOON THURSDAY WITH GUSTS UP TO 40 MPH IN THE MOUNTAINS
AND 25-30 MPH IN THE VALLEYS. HUMIDITIES THURSDAY WILL GENERALLY
RANGE FROM 10-15 PERCENT.

NORTHEAST WINDS ARE EXPECTED TO BE WEAKER THURSDAY NIGHT INTO FRIDAY
BUT STILL REMAIN GUSTY AT TIMES. VERY POOR HUMIDITY RECOVERIES ARE
EXPECTED THURSDAY NIGHT WITH WIDESPREAD SINGLE DIGIT HUMIDITIES
FRIDAY THROUGH SUNDAY.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH (SEE LAXRFWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).

&&
$$

PUBLIC...KJ
AVIATION/MARINE...RAT
FIRE WEATHER...WOFFORD
SYNOPSIS...SUKUP

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