Area Forecast Discussion
Issued by NWS Los Angeles, CA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KLOX 210536 AAA
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1030 PM PDT MON OCT 20 2014

UPDATED AVIATION SECTION

.SYNOPSIS...

A WEAK COLD FRONT WILL MOVE THROUGH THE AREA TONIGHT...BRINGING
LOCALLY GUSTY WINDS AND A SLIGHT CHANCE OF SHOWERS TO SOME NORTH
FACING MOUNTAIN SLOPES THROUGH TUESDAY MORNING. TEMPERATURES WILL
REMAIN NEAR NORMAL THROUGH TUESDAY...THEN ABOVE NORMAL TEMPERATURES
ARE EXPECTED FOR MID TO LATE WEEK AS WEAK OFFSHORE FLOW DEVELOPS.
COOLER WEATHER WILL LIKELY RETURN THIS WEEKEND WITH THE NEXT LOW
PRESSURE SYSTEM.

&&

.SHORT TERM (TONIGHT-WED)...
WEAK UPPER LEVEL TROUGH OF LOW PRESSURE MOVING THROUGH NORTHERN
AND CENTRAL CALIFORNIA THIS EVENING. TIGHTENING NORTHWEST PRESSURE
GRADIENT DEVELOPING ON THE BACK SIDE OF THIS UPPER TROUGH. ALREADY
SEEING SBA-SANTA MARIA GRADIENT CLIMBING TO -3.6 MB AS OF 8
PM...GENERATING NORTHWEST WINDS GUSTING UP TO 36 MPH AT LAS FLORES
CANYON. WIND ADVISORY LOOKS ON TRACK FOR SBA SOUTH COAST
TONIGHT...AS SBA-SANTA MARIA PRESSURE GRADIENT WILL LIKELY TREND
MORE OFFSHORE DURING NEXT FEW HOURS. THE NORTHWEST FLOW WILL ALSO
PILE UP SOME MOISTURE AND LOW CLOUDS ALONG THE INTERIOR SLOPES OF
THE MOUNTAINS AND INTERIOR VALLEYS OF SLO/SBA COUNTIES. THIS UPSLOPE
FLOW MAY ALSO GENERATE A FEW LIGHT SHOWERS ACROSS THE INTERIOR
MOUNTAIN SLOPES. OTHERWISE PASSAGE OF UPPER LEVEL TROUGH SHOULD
CONTINUE TO WEAKEN MARINE INVERSION. SO NOT EXPECTING MUCH IN THE
WAY OF ORGANIZED LOW CLOUDS AND FOG OVERNIGHT...WITH THE EXCEPTION
OF THE LA COUNTY COAST. GUSTY WEST TO NORTHWEST WINDS WILL ALSO
IMPACT THE INTERSTATE 5 CORRIDOR AND WESTERN ANTELOPE VALLEY THIS
EVENING BUT EXPECTED TO REMAIN BELOW ADVISORY LEVELS.

*** FROM PREVIOUS DISCUSSION ***

TEMPS ON TUE WILL TURN WARMER ALONG THE COAST AND ADJACENT VLYS TO
NEAR NORMAL FOR THE MOST PART...WITH READINGS STILL A FEW DEGREES
BELOW NORMAL ELSEWHERE.

WEAK UPPER LEVEL RIDGING WHICH SHOULD START TO BUILD INTO SWRN CA ON
TUE WILL BUILD FURTHER ACROSS SRN CA TUE NIGHT AND WED. OFFSHORE
FLOW...LIKELY BELOW ADVISORY LEVELS...WILL COVER MUCH OF THE
FORECAST AREA TUE NIGHT INTO WED MORNING. GUSTY N CANYON WINDS
SHOULD ALSO AFFECT THE SBA S COAST AND MTNS AGAIN...BUT REMAIN BELOW
ADVISORY LEVELS. THE NAM WAS FORECASTING A LINGERING EDDY OVER THE
SRN CA BIGHT INTO WED MORNING WHICH MAY BRING A FEW LOW CLOUDS TO
THE SRN L.A. COUNTY COAST. OVERALL... THOUGH...IT LOOKS LIKE MOSTLY
CLEAR SKIES WITH NEAR TO SLIGHTLY ABOVE NORMAL TEMPS CAN BE EXPECTED
TUE NIGHT AND WED.

FLAT UPPER LEVEL RIDGING WILL PERSIST OVER SRN CA WED NIGHT AND THU.
IT LOOKS LIKE MORE OFFSHORE FLOW BELOW ADVISORY LEVELS WILL AFFECT
THE AREA DURING THE NIGHT AND MORNING HOURS...EXCEPT THE L.A. COUNTY
COAST WILL REMAIN UNDER THE INFLUENCE OF A WEAK EDDY WITH LATE NIGHT
AND MORNING LOW CLOUDS AND FOG ONCE AGAIN EXPECTED. THE MOSTLY CLEAR
SKIES WILL CONTINUE ELSEWHERE WITH TEMPS WARMING A LITTLE MORE TO
SEVERAL DEGREES ABOVE NORMAL.

.LONG TERM (FRI-MON)...ECMWF/GFS IN PRETTY GOOD AGREEMENT FRI THRU
SAT WITH UPPER RIDGE LINGERING FRI THEN AN UPPER TROF APPROACHES THE
AREA FROM THE E PAC ON SAT. THE GFS DOES BRING A DISSIPATING COLD
FRONT INTO THE CENTRAL COAST ON SAT WITH A FEW SHOWERS POSSIBLE...
WHILE THE EC IS NOT AS FAST AND HOLDS OFF TIL LATE SAT AND SAT
EVENING. BIGGER DIFFERENCES SHOW UP SAT NIGHT INTO EARLY MON AS THE
GFS PASSES THE PROGRESSIVE UPPER TROF QUICKLY E SUN WITH UPPER RIDGE
BUILDING BACK IN BY LATE SUN...WHILE EC SLOWS UPPER TROF DOWN AND
DEVELOPS AN UPPER LOW OVER CENTRAL CA EARLY SUN WITH A BETTER CHANCE
OF RAIN OVER NORTHERN PARTS OF THE FORECAST AREA...THEN MOVES THIS
SYSTEM AWAY SUN AFTERNOON THRU MON AS AN UPPER RIDGE BUILDS IN MON.
TRENDED MORE TOWARD THE GFS SOLUTION AND TIMING OF DISSIPATING FRONT
WITH POSSIBLE SHOWERS OVER PORTIONS OF SLO/SBA COUNTIES SUN. SOME
MARINE LAYER CLOUDS MAY AFFECT THE L.A. COUNTY COAST NIGHT AND
MORNING HOURS...OTHERWISE CLEAR TO PARTLY CLOUDY SKIES ARE EXPECTED.
TEMPS SHOULD COOL SOME BACK TO NEAR NORMAL BY SAT THEN INCREASE TO
NEAR NORMAL TO SLIGHTLY ABOVE NORMAL BY MON.

&&

.AVIATION...21/0530Z.
THE MARINE LAYER AT KLAX AT 0500Z WAS 1000 FEET DEEP AND THE
INVERSION TOP IS AT 1500 FEET WITH A TEMPERATURE OF 19 DEGREES C.

MARINE INVERSION WILL REMAIN WEAK THROUGH THE PD. AS A RESULT...NOT
EXPECTING MUCH IN THE WAY OF ORGANIZED LOW CLOUD COVERAGE TONIGHT
ACROSS COASTAL/VALLEY TAF LOCATIONS. BEST CHANCE OF CIGS DEVELOPING
WOULD BE AT KLAX AND KLGB AND ON THE CENTRAL COAST...WITH MAINLY
MVFR TO LOCAL HIGH IFR CONDS EXPECTED.


KLAX...LOW TO MODERATE CONFIDENCE IN THE 06Z TAF. THERE IS A
30 TO 40 PERCENT CHANCE THAT CONDS WILL REMAIN VFR THRU THE PD.

KBUR...HIGH CONFIDENCE IN THE 06Z TAF. THERE IS A 10 TO 20 PERCENT
CHANCE OF IFR CONDITIONS BETWEEN 12Z AND 17Z.


&&

.MARINE...20/800 PM...
WIDESPREAD SMALL CRAFT ADVISORY CONDITIONS WILL CONTINUE TONIGHT
INTO TUESDAY MORNING ACROSS THE OUTER COASTAL WATERS. IN EVENING
UPDATE...HAVE UPGRADED TO GALE WARNINGS FOR ZONES 673/676 FOR TUESDAY
AFTERNOON INTO TUESDAY NIGHT.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY (SEE LAXCFWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).
SMALL CRAFT ADVISORY AND GALE WARNING (SEE LAXMWWLOX).

&&
$$

PUBLIC...GOMBERG/SIRARD
AVIATION...GOMBERG
MARINE...GOMBERG
SYNOPSIS...SUKUP

WWW.WEATHER.GOV/LOSANGELES













USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.