Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 260332
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
830 PM PDT SAT APR 25 2015

.SYNOPSIS...
THE GUSTY WINDS WILL SHIFT MORE NORTHERLY TONIGHT...AND THEN
NORTHEAST ON SUNDAY AS HIGH PRESSURE MOVES IN. THE HIGH AND OFFSHORE
WINDS WILL BRING FAIR SKIES AND ABOVE NORMAL TEMPERATURES INTO
MIDWEEK. BUT THE LAST HALF OF THE WEEK WILL HAVE A COOLING TREND
WITH AN INCREASING MARINE LAYER AS A LOW APPROACHES.

&&

.SHORT TERM (TONIGHT-TUE)...A FAST MOVING COLD FRONT MOVED THRU THE
FORECAST AREA TODAY. THERE WERE SCATTERED SHOWERS OVER PARTS OF L.A.
COUNTY LATE TODAY WHICH LINGERED INTO EARLY THIS EVENING. CLEAR TO
PARTLY CLOUDY SKIES SHOULD PREVAIL FOR MANY PARTS OF THE FORECAST
AREA OVERNIGHT. THE N MTN SLOPES WILL HAVE PLENTY OF LEFTOVER CLOUDS
ALONG WITH A CHANCE OF RAIN AND SNOW SHOWERS MAINLY ON THE N SLOPES.

GUSTY W TO NW WINDS BEHIND THE FRONT AFFECTED MANY PARTS OF THE
DISTRICT INTO THIS EVENING AS WELL. GUSTY ONSHORE WINDS TO ADVISORY
LEVELS CONTINUED EARLY THIS EVENING FOR THE VTU/L.A. COUNTY COASTAL
AREAS. THERE IS A WIND ADVISORY IN EFFECT FOR THESE AREAS UNTIL 9 PM
THIS EVENING...WHEN WINDS ARE EXPECTED TO DIMINISH. GUSTY W WINDS IN
THE ANTELOPE VALLEY WERE NOTED AS WELL..BUT WINDS NEVER REALLY GOT
AS STRONG AS ORIGINALLY THOUGHT...AND WILL LIKELY CANCEL THE HIGH
WIND WARNING AND POSSIBLY REPLACE WITH A WIND ADVISORY PRIOR TO 9 PM
THIS EVENING. GUSTY NW TO N WINDS WILL PERSIST ACROSS THE SBA S
COAST AND MTNS...WITH A WIND ADVISORY IN EFFECT UNTIL 3 AM SUNDAY.
850 MB WINDS WILL TURN NW TO N AND INCREASE RAPIDLY THIS EVENING TO
45 KNOTS OR SO...AND THIS WILL BRING STRONG AND DAMAGING WIND GUSTS
TO THE L.A./VTU MTNS ESPECIALLY ALONG THE I-5 CORRIDOR. A HIGH WIND
WARNING IS IN EFFECT FOR THESE AREAS OVERNIGHT INTO SUN MORNING. THE
NORTHERLY WINDS WILL DESCEND TO LOWER ELEVATIONS AND CAUSE GUSTY
NORTHERLY WINDS OVERNIGHT INTO SUN MORNING FOR THE SANTA CLARITA
VLY...SANTA MONICA MTNS AND SAN FERNANDO VLY...WHERE WIND ADVISORIES
ARE ALSO IN EFFECT. PLEASE SEE THE LATEST NON-PRECIPITATION WEATHER
MESSAGE FOR FURTHER DETAILS ON THE HIGH WIND WARNING AND WIND
ADVISORIES.

AN UPPER LEVEL TROF OVER SERN CA THIS EVENING WILL PUSH E INTO THE
GREAT BASIN TONIGHT AND SUN. UPPER LEVEL RIDGING WILL BUILD OFF THE
CA COAST THRU SUN...WITH A BROAD NORTHERLY FLOW ALOFT OVER SRN CA.
THE UPPER RIDGE WILL GRADUALLY BUILD INTO CENTRAL AND NRN CA SUN
NIGHT AND MON...WITH A N TO NE FLOW ALOFT FOR SRN CA. THE UPPER
LEVEL RIDGE AXIS IS THEN FORECAST TO MOVE INTO SRN CA FOR TUE.

DRIER AIR WILL CONTINUE TO MOVE INTO THE REGION ON THE NORTHERLY
FLOW FOR SUN WITH MOSTLY CLEAR SKIES EXPECTED IN ALL AREAS EXCEPT
THERE SHOULD BE A FEW LINGERING CLOUDS IN THE MORNING ON THE N MTN
SLOPES.

WINDS WILL TURN NE AND BE GUSTY OVER PORTIONS OF VTU/L.A.COUNTIES
LATER SUN NIGHT INTO MON MORNING...ESPECIALLY BELOW AND THRU THE
FAVORED PASSES AND CANYONS. IT LOOKS LIKE WIND ADVISORIES MAY BE
NEEDED BY EARLY MON MORNING FOR THE SANTA MONICA MTNS...VTU COUNTY
VLYS...SANTA CLARITA VLY...AND THE  WESTERN SAN FERNANDO VLY. 850 MB
WINDS SHOULD INCREASE TO 45 TO 50 KT OVER THE L.A./VTU MTNS...WITH
STRONG AND GUSTY NE WINDS EXPECTED THERE...POSSIBLY TO WARNING
LEVELS. A HIGH WIND WATCH MAY BE NEEDED FOR THESE AREAS FOR LATER
SUN NIGHT INTO MON MORNING. WINDS ACROSS THE AREA WILL DIMINISH MON
AFTERNOON. THERE WILL BE WEAKER OFFSHORE WINDS ACROSS THE REGION MON
NIGHT INTO TUE MORNING...BELOW ADVISORY LEVELS. SKIES WILL BE MOSTLY
CLEAR ACROSS THE REGION MON AND TUE WITH MUCH WARMER TEMPERATURES
EXPECTED DURING THE PERIOD.

TEMPS OVER SWRN CA ARE FORECAST TO WARM TO A FEW DEGREES ABOVE
NORMAL FOR MANY AREAS ON SUN...AND TO MUCH ABOVE NORMAL ON MON AND
TUE...WITH HIGHS APPROACHING 90 DEGREES IN THE WARMEST VLYS
MON...AND REACHING INTO THE LOWER 90S FOR THE WARMEST VLYS ON TUE.

***FROM PREVIOUS DISCUSSION***

.LONG TERM (WED-SAT)...WEAK UPPER TROUGH WILL BRING A RETURN OF
ONSHORE FLOW AND MARINE LAYER CLOUDS DURING THE EXTENDED PERIOD.
INITIALLY...THE LOW CLOUDS AND FOG ARE EXPECTED TO BE CONFINED TO
COASTAL AREAS...BUT SHOULD EXTEND FURTHER INLAND BY FRIDAY. THERE
WILL BE A GRADUAL COOLING TREND THROUGH THE EXTENDED PERIOD.

&&

.AVIATION...26/0020Z.

AT 2330Z...THERE WAS NO MARINE INVERSION PRESENT AT KLAX.

GENERALLY HI CONFIDENCE IN THE 00Z TAFS...ALTHO THERE IS SOME
UNCERTAINTY WITH THE TIMING AND EXTENT OF MVFR CIGS AT TIMES TONIGHT
INTO EARLY SUN FOR SEVERAL OF THE COAST AND VLY AIRFIELDS...WITH THE
TIMING OFF PLUS/MINUS ONE TO TWO HOURS. HI CONFIDENCE DRIER AIR
MOVING IN TONIGHT AND SUN WILL CLEAR TO THE AIRFIELDS TO
VFR...STARTING TONIGHT FOR AREAS S OF POINT CONCEPTION...AND
ELSEWHERE EARLY SUN MORNING. HI CONFIDENCE IN 00Z TAFS FOR KWJF AND
KPMD WITH VFR CONDITIONS THRU SUN. GUSTY W TO NW WINDS FOR COASTAL
AIRFIELDS WILL DIMINISH TONIGHT. AT KSBA...LOW LEVEL WIND SHEAR IS
EXPECTED 02Z-11Z DUE TO GUSTY N CANYON WINDS IN THE VICINITY. GUSTY
W WINDS AT KWJF AND KPMD WILL PERSIST TONIGHT INTO SUN MORNING.

KLAX...GENERALLY HI CONFIDENCE IN THE 00Z TAF...ALTHO THERE IS SOME
UNCERTAINTY WITH THE TIMING OF MVFR CIGS IMPROVING TO VFR WHICH MAY
BE OFF PLUS/MINUS ONE TO TWO HOURS. ONCE CLEARING TAKES PLACE...HI
CONFIDENCE DRIER AIR MOVING IN WILL KEEP VFR CONDITIONS AT THE
AIRFIELD THRU SUN EVENING. GUSTY W WINDS THIS EVENING WILL DIMINISH
TONIGHT.

KBUR...GENERALLY HI CONFIDENCE IN THE 00Z TAF...ALTHO THERE IS SOME
UNCERTAINTY WITH THE TIMING OF MVFR CIGS IMPROVING TO VFR WHICH MAY
BE OFF PLUS/MINUS ONE TO TWO HOURS. ONCE CLEARING TAKES PLACE AROUND
05Z...HI CONFIDENCE DRIER AIR MOVING IN WILL KEEP VFR CONDITIONS AT
THE AIRFIELD THRU SUN AFTERNOON.

&&

.MARINE...25/800 PM...
NORTHWEST WINDS WILL CONTINUE TO INCREASE OVER THE WATERS THIS
EVENING...STRONGEST OVER THE OUTER WATERS WHERE GUSTS 35 TO 40 KNOTS
ARE EXPECTED TO BE WIDESPREAD. THE INNER WATERS WILL ALSO SEE
MODERATE TO STRONG GUSTS...AND THERE IS A GALE WARNING IN EFFECT
OVERNIGHT FOR THE SOUTHERN INNER WATERS...PZZ650 AND PZZ655.

THE PERIOD WITH THE STRONGEST AND MOST WIDESPREAD GALE FORCE WINDS
WILL BE SUNDAY AFTERNOON THROUGH SUNDAY EVENING. STEEP COMBINED SEAS
WILL LIKELY BUILD TO 9 TO 12 FEET IN THE OUTER WATERS AND 6 TO 8
FEET IN THE NEAR SHORE BASINS OVERNIGHT INTO SUNDAY...SUBSIDING LATE
SUNDAY NIGHT.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING (SEE LAXNPWLOX).
WIND ADVISORY (SEE LAXNPWLOX).
GALE WARNING (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).

&&

$$

PUBLIC...SIRARD/GOMBERG
AVIATION...SIRARD
MARINE...SMITH
SYNOPSIS...SETO

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