114
FXUS66 KLOX 130548
AFDLOX
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1045 PM PDT MON AUG 12 2013
UPDATED AVIATION DISCUSSION
.SYNOPSIS...
TEMPERATURES ARE EXPECTED TO RETURN TO NORMAL OR A LITTLE ABOVE BY
MIDWEEK AS THE RIDGE CONTINUES TO SLOWLY BUILD INTO THE AREA. NIGHT
THROUGH MORNING LOW CLOUDS AND FOG SHOULD BE MAINLY CONFINED TO THE
COASTAL PLAIN THE REST OF THE WEEK. A WEAK TROUGH MAY COOL
TEMPERATURES A COUPLE DEGREES OVER THE WEEKEND.
&&
.SHORT TERM (TONIGHT-THU)...DOWNTOWN LOS ANGELES HAD A HIGH OF 79
DEGREES TODAY...FOR THE 17TH CONSECUTIVE DAY THE HIGH THERE DID NOT
REACH 80. THIS INCLUDES 12 CONSECUTIVE SUB-80 DEGREE HIGHS TO START
THE MONTH OF AUGUST...SETTING A NEW RECORD. THE AVERAGE HIGH FOR
AUGUST 2013 AT DOWNTOWN L.A. THRU TODAY IS 77.5 DEGREES WHICH IS 6.9
DEGREES BELOW NORMAL. IT LOOKS LIKE THIS STRETCH OF BELOW 80 DEGREE
HIGHS WILL END ON TUESDAY AS THE FORECAST HIGH FOR DOWNTOWN IS 81.
THE MARINE INVERSION WAS NEAR 1200 FT DEEP AT LAX EARLY THIS
EVENING. LOW CLOUDS WERE MOVING INTO PORTIONS OF THE CENTRAL COAST
THIS EVENING AND WILL CONTINUE TO EXPAND ALONG THE COAST AND INLAND
TO THE SANTA YNEZ VALLEY OVERNIGHT. LOW CLOUDS WERE ALSO NOTED ALONG
PORTIONS OF THE VTU/L.A. COUNTY COASTAL AREAS...AND ARE EXPECTED TO
GRADUALLY EXPAND ALONG THE COAST AND PUSH INLAND TO THE SOME OF THE
ADJACENT VALLEYS OVERNIGHT IN RESPONSE TO THE DEVELOPMENT OF A WEAK
EDDY. THE S COAST OF SBA COUNTY SHOULD REMAIN MOSTLY CLEAR UNTIL
VERY LATE TONIGHT OR EARLY TUE. OTHERWISE...MOSTLY CLEAR SKIES WILL
PREVAIL OVER THE REGION THRU THE NIGHT.
THE LATEST MODEL RUNS INDICATED THAT A BROAD UPPER LEVEL TROF WILL
LINGER ALONG AND OFF THE CA COAST THRU TUE NIGHT...THEN UPPER
RIDGING WILL SLOWLY BUILD INTO SRN CA FROM THE E WED THRU THU. THE
MARINE LAYER PATTERN WITH VARYING AMOUNTS OF NIGHT AND MORNING LOW
CLOUDS AND FOG WILL PREVAIL MAINLY FOR PORTIONS OF THE COASTAL PLAIN
THE PERIOD. OTHERWISE...MOSTLY CLEAR SKIES WILL CONTINUE OVER THE
FORECAST AREA THROUGH THU. DECENT ONSHORE FLOW CAN BE EXPECTED FOR
THE AFTERNOON AND EVENING HOURS...WITH SOME GUSTY WINDS EXPECTED FOR
PORTIONS OF THE MTNS AND ACROSS THE ANTELOPE VALLEY. THERE SHOULD
ALSO BE SOME OFFSHORE FLOW LATER AT NIGHT INTO THE MORNING FOR
INTERIOR AREAS OF SLO/SBA COUNTIES. TEMPS ARE EXPECTED TO WARM TO
NEAR NORMAL TO SEVERAL DEGREES ABOVE NORMAL FOR TUE AND WED...THEN
WARM FURTHER TO ABOVE NORMAL FOR MANY AREAS ON THU.
***FROM PREVIOUS DISCUSSION***
.LONG TERM (FRI-MON)...OVERALL...12Z MODELS CONTINUE TO EXHIBIT GOOD
SYNOPTIC AGREEMENT THROUGH THE PERIOD. AT UPPER LEVELS...RIDGE WILL
PEAK IN STRENGTH ON FRIDAY...THEN WILL BE SQUASHED A BIT SATURDAY
AND SUNDAY AS A WEAK TROUGH ZIPS ACROSS NORTHERN CALIFORNIA...THEN
THE RIDGE WILL RECOVER ON MONDAY. NEAR THE SURFACE...EAST/WEST
GRADIENTS WILL REMAIN ONSHORE WHILE NORTH/SOUTH GRADIENTS REMAIN
WEAKLY OFFSHORE.
FORECAST-WISE...ONLY MINOR CHANGES ARE EXPECTED THROUGH THE PERIOD.
TEMPERATURES WILL LIKELY EXHIBIT A SLIGHT COOLING TREND THROUGH THE
PERIOD BUT WILL STILL HOVER NEAR SEASONAL NORMS. AS FOR THE MARINE
LAYER STRATUS...WILL EXPECT A SLIGHT INCREASE IN DEPTH AND INLAND
EXTENT...BUT THE MARINE LAYER ITSELF MAY HAVE DIFFERENT IDEAS.
&&
.AVIATION...13/0545Z...EXPECT WIDESPREAD STRATUS IN ALL COASTAL
AREAS...ARRIVING LAST ACROSS THE S COAST OF SANTA BARBARA COUNTY.
SOME CLOUDS MAY SNEAK INTO THE LOWER COASTAL VLYS OF L.A. AND VTU
COUNTIES AND THE SANTA YNEZ VALLEY OVERNIGHT. CONDS WILL BE
GENERALLY IFR IN THESE AREAS. EXPECT FAIRLY QUICK CLEARING BY MID OR
LATE MORNING ACROSS THE REGION. LESS IN THE WAY OF INLAND
PENETRATION OF STRATUS EXPECTED TUE NIGHT.
KLAX...MODERATE CONFIDENCE IN THE 06Z TAF. THERE IS A 20 PERCENT
CHANCE CIGS WILL SCATTER OUT BETWEEN 06Z AND 10Z. THERE IS A 10 TO
20 PERCENT CHANCE CIGS WILL LINGER AT IFR LEVELS THROUGH 19Z OR
20Z.
KBUR...MODERATE CONFIDENCE IN THE 06Z TAF. THERE IS A 20 TO 30
PERCENT CHANCE IFR CIGS BETWEEN 10Z AND 16Z.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
&&
$$
PUBLIC...SIRARD/RAT
AVIATION...SIRARD
SYNOPSIS...B
WWW.WEATHER.GOV/LOSANGELES