782 
FXUS66 KLOX 222356 AAA
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
455 PM PDT SAT AUG 22 2015

...UPDATED AVIATION DISCUSSION...

.SYNOPSIS...

HIGH PRESSURE WILL LOCK INTO PLACE OVER THE FOUR CORNERS REGION 
THROUGH NEXT WEEKEND. AS A RESULT...MORNING CLOUDS WILL RETREAT TO 
THE COAST BEFORE BREAKING UP DURING THE WEEK WITH GENERALLY ABOVE 
NORMAL TEMPERATURES. A GRADUAL RETURN OF MORNING CLOUDS IS EXPECTED 
THURSDAY INTO THE WEEKEND WITH LOW PRESSURE LURKING OFF THE COAST.

&& 

.SHORT TERM (TODAY-TUE)...

ONSHORE FLOW CONTINUES TO WEAKEN THIS AFTERNOON AS HIGH PRESSURE 
BUILDS OVER THE WEST. KLAX-KDAG SURFACE PRESSURE GRADIENTS ARE 
STARTING TO TREND MORE STRONGLY OFFSHORE THIS AFTERNOON...AND THE 
TREND SHOULD CONTINUE INTO TUESDAY. THERE IS A CHANCE THAT THE KSMX-
KBFL SURFACE PRESSURE GRADIENTS COULD TURN OFFSHORE BY MONDAY OR 
TUESDAY MORNING. THE MARINE LAYER...CURRENTLY NEAR 1800 FEET...WILL 
CONTINUE TO THIN THROUGH TUESDAY AND COULD BECOME DIFFICULT TO FORM 
AFTER MONDAY. THE MARINE LAYER INDUCED STRATUS WILL LIKELY BECOME 
CONFINED TO THE COAST BY TUESDAY AT THE LATEST. WITH ONSHORE 
WEAKENING ACROSS THE AREA...A WARMING TREND WILL DEVELOP THROUGH 
EARLY NEXT WEEK. IN THE CURRENT PACKAGE...A WARMING TREND REMAINS IN 
TACT FOR THE SHORT-TERM PERIOD. MODERATE TO HIGH CONFIDENCE EXISTS 
IN THE FORECAST THROUGH MONDAY...BUT SOME MONSOONAL MOISTURE COULD 
SCRAPE THE AREA BETWEEN TUESDAY AND WEDNESDAY.

BOTH NAM-WRF AND GFS SOLUTIONS SUGGEST MOISTURE...MAINLY AT THE 
MIDDLE LEVELS INCREASING BETWEEN MONDAY AND TUESDAY. WHILE SHOWERS 
AND THUNDERSTORMS CANNOT BE RULED OUT WITH THIS PATTERN...HIGHER 
CONFIDENCE EXISTS IN MIDDLE-LEVEL CLOUDS STREAMING OVER THE AREA FOR 
TUESDAY. SKY COVER AND POPS HAVE BEEN INCREASED AT THIS TIME. LOWER 
CONFIDENCE EXISTS IN THE MARINE LAYER STRATUS COVERAGE BETWEEN 
MONDAY NIGHT AND TUESDAY MORNING...AND AGAIN ON TUESDAY NIGHT INTO 
WEDNESDAY MORNING. THERE COULD BE NO STRATUS AT ALL BY TUESDAY 
MORNING AS THE MIDDLE-LEVEL CLOUD DECK PLAYS TRICKS WITH THE MARINE 
LAYER AND COOLS THE TOP OF THE MARINE INVERSION.

.LONG TERM (WED-SAT)...

HIGH PRESSURE SHOULD REMAIN IN PLACE THROUGH THURSDAY AND KEEP A 
VERY WARM WEATHER PATTERN OVER THE AREA. HOWEVER...MODEL SOLUTIONS 
ARE STARTING TO HINT AT SOUTHWEST FLOW ALOFT REDEVELOPING FOR LATE 
NEXT WEEK AS A TROUGH OF LOW PRESSURE OVER THE EASTERN PACIFIC 
STARTS TO REPLACE THE RIDGE. CONFIDENCE IS GROWING FOR A COOLER PART 
OF THE WEEK TOWARDS LATE WEEK AND INTO NEXT WEEKEND. THE MARINE 
LAYER STRATUS SHOULD RETURN FOR LATE NEXT WEEK AS ONSHORE FLOW 
STARTS TO INCREASE. TEMPERATURES HAVE BEEN COOLED IN THE FORECAST 
BUT STILL COULD BE TOO WARM FOR LATE NEXT WEEK.

&&

.AVIATION...22/2350Z

AT 2258Z AT KLAX THE MARINE LAYER WAS AROUND 1500 FT DEEP. THE TOP 
OF THE INVERSION WAS AROUND 4800 FEET WITH A TEMPERATURE OF 25 
DEGREES CELSIUS.

GENERALLY HI CONFIDENCE IN THE 00Z TAFS. LOW CLOUDS AND 
LIFR/IFR/MVFR CIGS WILL AFFECT ALL THE COASTAL AND ADJACENT VLY 
AIRFIELDS INCLUDING KPRB STARTING AROUND 05Z AT KSMX...AND BETWEEN 
07Z AND 14Z ELSEWHERE...ALTHO THE TIMING OF THE ONSET OF THE LOW 
CLOUDS MAY BE OFF PLUS/MINUS AN HOUR OR TWO. THE LOW CLOUDS WILL 
CLEAR TO VFR AT THE AIRFIELDS BY LATE SUN MORNING TO EARLY SUN 
AFTERNOON. FOR KPMD AND KWJF...VFR CONDITIONS ARE EXPECTED THRU SUN. 
GUSTY SW WINDS WILL PERSIST AT THESE AIRFIELDS BEFORE DIMINISHING 
OVERNIGHT...THEN INCREASE AGAIN ON SUN AFTERNOON.

KLAX...GENERALLY HI CONFIDENCE IN THE 00Z TAF. LOW CLOUDS AND MVFR 
CIGS WILL AFFECT THE AIRFIELD STARTING AROUND 07Z...ALTHO THE TIMING 
OF THE ONSET OF THE LOW CLOUDS MAY BE AN HOUR OR TWO TOO LATE. THE 
LOW CLOUDS WILL CLEAR TO VFR BY 19Z SUN...WITH VFR CONDITIONS 
EXPECTED THRU SUN EVENING.

KBUR...GENERALLY HI CONFIDENCE IN THE 00Z TAF. VFR CONDITIONS WILL 
PREVAIL THIS EVENING. LOW CLOUDS AND MVFR CIGS WILL AFFECT THE 
AIRFIELD STARTING AROUND 10Z...ALTHO THE TIMING OF THE ONSET OF THE 
LOW CLOUDS MAY BE OFF PLUS/MINUS AN HOUR OR TWO. THE LOW CLOUDS WILL 
CLEAR TO VFR BY 18Z SUN...WITH VFR CONDITIONS EXPECTED THRU SUN 
AFTERNOON.

&&

.MARINE...22/200 PM. 

SMALL CRAFT ADVISORY CONDITIONS ARE NOT EXPECTED THROUGH SUNDAY 
AFTERNOON. THERE IS A SLIGHT CHANCE SCA CONDITIONS WITH WEST AND 
NORTHWEST WINDS WILL DEVELOP IN THE VICINITY OF SANTA ROSA AND SAN 
MIGUEL ISLANDS SUNDAY EVENING AND PERSIST THROUGH EARLY MONDAY 
MORNING. THERE IS A CHANCE SCA CONDITIONS WITH NORTHWEST WINDS WILL 
EXIST FROM POINT SAL TO NW OF SAN NICOLAS ISLAND MONDAY EVENING 
THROUGH TUESDAY MORNING AND AGAIN TUESDAY EVENING THROUGH WEDNESDAY 
MORNING.

&&

.FIRE WEATHER...22/1615Z.

INTERIOR SECTIONS AWAY FROM THE MARINE LAYER WILL REMAIN DRY THROUGH 
THE WEEKEND. THE ANTELOPE VALLEY...MOUNTAINS...AND INTERIOR VALLEYS 
WILL GENERALLY SEE HUMIDITY READINGS BETWEEN 10 AND 20 PERCENT 
THOUGH THE WEEKEND...WITH ISOLATED SINGLE DIGIT READINGS. GUSTY 
ONSHORE WINDS WILL IMPACT INTERIOR AREAS DURING THE AFTERNOON AND 
EVENING HOURS THIS WEEKEND...WITH GUSTS GENERALLY BETWEEN 25 AND 35 
MPH. THE COMBINATION OF THE GUSTY ONSHORE WINDS...VERY WARM 
TEMPERATURES...AND LOW HUMIDITIES WILL BRING ELEVATED FIRE DANGER TO 
THE ANTELOPE VALLEY...MOUNTAINS...AND INTERIOR VALLEYS THROUGH THE 
WEEKEND...WITH BRIEF CRITICAL FIRE WEATHER CONDITIONS POSSIBLE EACH 
AFTERNOON. 

A PROLONGED PERIOD OF HOT AND DRY CONDITIONS ACROSS INTERIOR 
SECTIONS NEXT WEEK. TRIPLE DIGIT HEAT IS EXPECTED ACROSS WARMEST 
VALLEYS...MOUNTAINS...AND DESERTS BY TUESDAY...BECOMING MORE 
WIDESPREAD WEDNESDAY THROUGH SUNDAY. THE PEAK OF THE HEAT WAVE IS 
EXPECTED TO OCCUR THURSDAY THROUGH SATURDAY WHEN WARMEST VALLEY 
LOCATIONS COULD CLIMB TO AROUND 105 DEGREES. DURING THIS 
TIME...HUMIDITIES WILL GENERALLY BE IN THE TEENS ACROSS INTERIOR 
SECTIONS...WITH SOME ISOLATED SINGLE DIGIT READINGS TOWARDS THE END 
OF NEXT WEEK. DUE TO THE POTENTIAL FOR AN EXTENDED HEAT WAVE WITH 
LOW HUMIDITIES MUCH OF NEXT WEEK...ELEVATED FIRE DANGER WILL 
CONTINUE ACROSS INTERIOR SECTIONS. THE GREATEST FIRE DANGER WILL 
SHIFT TO THE FOOTHILLS AND MOUNTAINS NEXT WEEK...WHERE THERE WILL 
ALSO BE POOR OVERNIGHT HUMIDITY RECOVERIES.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

PUBLIC...HALL
AVIATION...SIRARD
MARINE...30
FIRE WEATHER...GOMBERG
SYNOPSIS...MUNROE

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