Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 030237
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
737 PM PDT TUE SEP 2 2014

.SYNOPSIS...
A WEAK TROUGH OF LOW PRESSURE OVER THE WEST COAST WILL MAINTAIN
COOLER TEMPERATURES THROUGH THURSDAY. UPPER RIDGING WILL THEN BRING
A FEW DEGREES OF WARMING FRIDAY INTO THE WEEKEND. ANOTHER TROUGH
WILL APPROACH LATE SUNDAY INTO MONDAY...WITH COOLER TEMPERATURES
EXPECTED AGAIN EARLY NEXT WEEK. OVERNIGHT LOW CLOUDS AND FOG WILL
CONTINUE FOR THE COAST AND VALLEYS INTO NEXT WEEK.

&&
.UPDATE...ONLY MINOR CHANGES NEEDED FOR THIS EVENING`S UPDATE. GUSTY
SOUTHWEST WINDS ARE AFFECTING THE MOUNTAIN PASSES INTO THE ANTELOPE
VALLEY AND SOME CANYONS OF THE SANTA MONICA MOUNTAINS. GUSTS ARE
GENERALLY 25 TO 35 MPH EXCEPT FOR ISOLATED GUSTS 40-45 MPH NEAR LAKE
PALMDALE. OTHERWISE FAIRLY QUIET WEATHER IS EXPECTED THROUGH THE
SHORT TERM. A WEAK TROUGH OF LOW PRESSURE OVER THE WEST COAST WILL
MAINTAIN COOLER THAN NORMAL TEMPERATURES THROUGH THURSDAY ALONG WITH
A MARINE LAYER OF 2000 TO 3000 FT. THIS DEEP MARINE LAYER WILL ALLOW
LOW CLOUDS TO MOVE WELL INLAND TONIGHT...ACROSS THE COASTAL VALLEYS
TO THE INTERIOR VALLEYS SUCH AS THE SANTA CLARITA AND SANTA YNEZ
VALLEYS. BY FRIDAY THE UPPER TROUGH WILL WEAKEN AND PUSH INLAND AS
AN UPPER RIDGE MOVES OVER THE WEST COAST. THIS WILL BRING
TEMPERATURES CLOSE TO NORMAL IN SOME LOCATIONS FRIDAY AFTERNOON.

.LONG TERM (SAT-TUE)...THE WARMING TREND THAT WILL START FRIDAY WILL
PEAK SATURDAY AS SURFACE HIGH PRESSURE STRENGTHENS OVER THE GREAT
BASIN AND GRADIENTS TURN ALMOST NEUTRAL. MODELS DON`T HAVE THE UPPER
HIGH QUITE THAT STRONG YET SO THE AIR MASS AS A WHOLE ISN`T ALL THAT
HOT. HOWEVER, THE GRADIENTS ALONE SHOULD BE ENOUGH TO PUSH SURFACE
TEMPS UP SEVERAL DEGREES, ESPECIALLY AT LOWER ELEVATIONS. LOCAL
TEMPERATURE STUDIES SUGGEST VALLEY HIGHS AROUND 100 SAT AND ECMWF
GUIDANCE SHOWS THIS AS WELL. HAVE BUMPED UP HIGHS A FEW DEGREES FROM
PREVIOUS FORECAST BUT NOT QUITE THAT HIGH YET.

THE TROF RETURNS SUN AND EARLY NEXT WEEK AND WILL BRING TEMPS BACK
TO NORMAL OR EVEN SLIGHTLY BELOW NORMAL. NOT SEEING ANY SIGN OF
MONSOON OR TROPICAL MOISTURE MOVING UP THIS WAY THE NEXT 10 DAYS AT
LEAST. NEWLY NAMED TS NORBERT WILL MOVE UP THE BAJA COAST LATE THIS
WEEK BUT IS EXPECTED TO STALL OUT AND FADE WELL BEFORE IT REACHES
OUR AREA. MEANWHILE THE TROF WILL LIKELY DEFLECT ANY OF IT`S
MOISTURE WELL EAST AND SOUTH OF US SO BASICALLY ZERO IMPACT EXCEPT
POSSIBLY SOME SOUTHERLY SWELLS.

&&

.AVIATION...03/0000Z.
OVERALL HIGH CONFIDENCE IN 00Z TAFS. A DEEP MARINE LAYER IN PLACE
OVER THE AREA WILL BRING LOW CLOUDS TO THE COAST AND VALLEYS
OVERNIGHT INTO WEDNESDAY MORNING. THE TIMING OF LOW CLOUD ARRIVAL
MAY DIFFER UP TO 2 HRS FROM TAF TIMES AND SOME LOCATIONS NEAR THE
COAST MAY EXPERIENCE SLOWER DISSIPATION OF LOW CLOUDS WEDNESDAY
AFTERNOON. GUSTY SW WINDS ARE EXPECTED FOR THE INTERIOR.

KLAX...MODERATE TO HIGH CONFIDENCE IN THE 00Z TAFS. HIGH CONFIDENCE
IN MVFR CIGS MOVING OVER THE AIRFIELD THIS EVENING AND PERSISTING
INTO WEDNESDAY. MODERATE CONFIDENCE IN THE TIMING AS LOW CLOUDS MAY
ARRIVE +/- 2 HRS FROM TAF TIME OF 04Z AND CLEARING MAY BE DELAYED UP
TO 2 HRS BEYOND FORECAST TIME OF 22Z.

KBUR...MODERATE TO HIGH CONFIDENCE IN THE 00Z TAFS. EXPECT MVFR CIGS
WITH A 20% CHANCE OF IFR CIGS DUE TO LOW CLOUDS TONIGHT INTO WED
MORNING. LOW CLOUD TIMING MAY DIFFER UP TO 2 HRS FROM TAF TIMES.

&&

.MARINE...02/730 PM...
HIGH PRESSURE WEST OF PORTLAND INTERACTING WITH LOWER PRESSURE OVER
THE CALIFORNIA COAST HAS PRODUCED GUSTY NORTHWEST WINDS OVER THE
OUTER WATERS ONCE AGAIN TONIGHT. EXPECT THE WINDS TO DIMINISH BY
EARLY WEDNESDAY MORNING. THIS PATTERN IS LIKELY TO REPEAT EACH
AFTERNOON/EVENING PERIOD THROUGH LATE IN THE WEEK WITH PZZ670-676
SEEING NW WINDS 10-20 KT WITH AT LEAST LOCAL GUSTS TO 25 KT. FOR THE
NEARSHORE WATERS...MAINLY LIGHT WEST TO NW WINDS ARE
EXPECTED...ALTHOUGH THE WESTERN PORTION MAY SEE GUSTS OF 15-20 KT
DURING THE LATE AFTERNOON TO EVENING PERIODS.

&&

.BEACHES...02/730 PM...

A LONG PERIOD SOUTH SWELL (2-4 FT AT 18-20 SECONDS) ORIGINATING FROM
THE SOUTHERN HEMISPHERE WILL BEGIN TO MOVE INTO THE COASTAL WATERS
THURSDAY INTO THURSDAY NIGHT...THEN PEAK FRIDAY THROUGH SUNDAY.
ELEVATED SURF AND HIGH RIP CURRENT RISK WILL BE LIKELY ACROSS SOUTH
FACING BEACHES OF LOS ANGELES AND VENTURA COUNTIES DURING THIS TIME.
WHILE THE SURF HEIGHTS WILL MUCH LOWER THAN THOSE WE SAW WITH
HURRICANE MARIE...THERE IS A CHANCE THAT HIGH SURF ADVISORY
THRESHOLDS OF 7 FEET OR GREATER WILL OCCUR ACROSS FAVORED SOUTH
FACING SHORES.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
NONE

&&

$$

PUBLIC...MW/SMITH
AVIATION...SMITH
MARINE...SMITH

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