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 122152
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
152 PM PST FRI FEB 12 2016

.SYNOPSIS...

A FAST MOVING LOW WILL BRING SOME CLOUDS AND COOLER TEMPERATURES
ON SATURDAY. THE HIGH WILL THEN REBUILD OVER THE REGION AND WITH
OFFSHORE WINDS SHOULD WARM TEMPERATURES TO NEAR RECORDS FOR EARLY
NEXT WEEK. A LOW SYSTEM WILL ARRIVE BY MIDWEEK FOR POSSIBLE
PRECIPITATION AND A COOLING TREND INTO THE WEEKS END.

&&

.SHORT TERM...(TDY-MON)

OVERALL...12Z MODELS IN GOOD SYNOPTIC AGREEMENT THROUGH THE
PERIOD. AT UPPER LEVELS...WEAK TROUGH MOVES ACROSS THE AREA
LATE TONIGHT/SATURDAY...THEN RIDGE BUILDS BACK IN FROM THE WEST ON
SUNDAY/MONDAY. NEAR THE SURFACE...OFFSHORE GRADIENTS WILL CONTINUE
TO WEAKEN TONIGHT/SATURDAY...THEN THE OFFSHORE GRADIENTS
STRENGTHEN AGAIN SUNDAY/MONDAY.

FORECAST-WISE...MAIN CONCERN IN THE SHORT TERM WILL BE WINDS. WITH
THE WEAKENING OFFSHORE GRADIENTS TONIGHT/SATURDAY...DO NOT
ANTICIPATE ANY WIND ISSUES. HOWEVER BEGINNING SATURDAY NIGHT AND
SUNDAY...THE FLOW TURNS NORTHERLY BEHIND THE UPPER TROUGH. AT THIS
TIME...THE NORTHERLY WINDS DO NOT LOOK TO BE TOO STRONG AS UPPER
SUPPORT IS NOT TOO GREAT. BY SUNDAY AFTERNOON...THE FLOW TURNS
NORTHEAST...AND REMAINS NORTHEAST THROUGH MONDAY AND STRENGTHENS.
THE NAM IS FORECASTING AN IMPRESSIVE -7.5 MB GRADIENT FROM LAX TO
DAGGETT MONDAY MORNING. SO...THERE WILL SHOULD BE A GOOD OFFSHORE
SURFACE GRADIENT ON MONDAY. AS FOR UPPER LEVEL SUPPORT ON MONDAY
THE NAM INDICATES 40-50 KNOT WINDS IN THE LOWER ATMOSPHERE WHILE
EVEN THE GFS INDICATES 30-35 KNOTS. SO...WITH THE COMBO OF A
STRONG OFFSHORE GRADIENT AND DECENT UPPER LEVEL WIND SUPPORT...IT
LOOKS LIKES A HIGH LIKELIHOOD OF A MODERATE SANTA ANA WIND EVENT
LATE SUNDAY NIGHT AND MONDAY. WIND ADVISORIES WILL BE LIKELY FOR
MOST AREAS OF VENTURA AND LOS ANGELES COUNTIES.

OTHERWISE...THE UPPER LEVEL PATTERN WILL ALLOW FOR VARYING AMOUNTS
OF CIRRUS CLOUDS TO DRIFT OVERHEAD THROUGH THE WEEKEND...BUT
CLOUDS WILL NOT BE TOO THICK. AS FOR STRATUS...THERE IS A CHANCE
OF SOME COASTAL STRATUS/FOG TONIGHT/SATURDAY MORNING...ESPECIALLY
ALONG THE CENTRAL COAST. HOWEVER...GIVEN THE BOUNDARY LAYER
PATTERN OF THE HIGH RES MODELS...WILL KEEP THE FORECAST STRATUS-
FREE TONIGHT/SATURDAY.

AS FOR TEMPERATURES...SATURDAY WILL BE A BIT COOLER THAN TODAY BUT
STILL ABOVE NORMAL. FOR SUNDAY AND MONDAY...ANOTHER WARMING TREND
WILL BEGIN. IN FACT BY MONDAY...THERE WILL BE THE POTENTIAL FOR
RECORD OR NEAR-RECORD HIGH TEMPERATURES FOR SOME COASTAL/VALLEY
AREAS.


.LONG TERM...(TUE-FRI)

FOR THE EXTENDED...12Z MODELS START OUT IN DECENT SYNOPTIC
AGREEMENT...BUT DIVERGE LATER IN THE PERIOD. AT UPPER LEVELS
RIDGE WILL LINGER ON TUESDAY THEN A TROUGH WILL APPROACH AND MOVES
ACROSS THE WEST COAST WEDNESDAY THROUGH FRIDAY. NEAR THE SURFACE
WEAK OFFSHORE FLOW WILL PREVAIL ON TUESDAY THEN SHIFT TO ONSHORE
WEDNESDAY THROUGH FRIDAY.

FORECAST-WISE...TUESDAY WILL BE AN UNREMARKABLE DAY WITH CLEAR
SKIES...LIGHT OFFSHORE BREEZES AND HIGH TEMPERATURES WELL ABOVE
NORMAL. FOR WEDNESDAY AND THURSDAY...THE MODELS DIVERGE NOTICEABLY
LEADING TO A LOW CONFIDENCE FORECAST. THE ECMWF MOVES A TROUGH
ACROSS THE AREA WEDNESDAY/THURSDAY AND GENERATES A DECENT RAIN
EVENT FOR THE AREA. CONVERSELY...THE GFS IS MUCH LESS BULLISH WITH
THIS TROUGH...HARDLY SPITTING OUT ANY PRECIPITATION. WITH SUCH
MODELS DIFFERENCES...WILL NOT DEVIATE FROM PREVIOUS FORECAST
THINKING WHICH INCLUDED CHANCE/SLIGHT CHANCE POPS FOR THE AREA
WEDNESDAY AND THURSDAY. HOPEFULLY...MODELS WILL COME INTO SOME
BETTER AGREEMENT OVER THE NEXT COUPLE OF DAYS. BY THURSDAY NIGHT
AND FRIDAY...BOTH MODELS PUSH TROUGH EAST OF THE AREA AND INDICATE
DRY CONDITIONS.


&&

.AVIATION...12/1800Z.

UPPER LEVEL TROUGH OF LOW PRESSURE UPSTREAM WILL SHIFT SOUTHEAST
WHILE A MID LEVEL RIDGE OF HIGH PRESSURE BUILDS OVER THE AREA. UPPER
LEVEL MODERATE SOUTHWEST WINDS WILL BECOME MODERATE NORTH BY
14/00Z WHILE MID LEVEL LIGHT AND VARIABLE WINDS BECOME LIGHT
NORTH-NORTHWEST AFTER 12/17Z. MIXED WEAK ONSHORE AND NORTHERLY
GRADIENT THROUGH 13/02Z THEN WEAK TO MODERATE NORTHERLY GRADIENT
BETWEEN 13/03-13/20Z AND THEN MIXED WEAK ONSHORE AND WEAK TO
MODERATE NORTHERLY GRADIENT.

MARINE LAYER AT LAX AT 1600Z IS NONE.

KLAX...THERE IS A CHANCE VSBY 5SM BR BETWEEN 13/12-12/17Z
OTHERWISE CURRENT SKY/VSBY CONDITIONS WILL LIKELY EXIST.

KBUR...CURRENT SKY/VSBY CONDITIONS WILL VERY LIKELY PERSIST
THROUGH THE PERIOD.

VIRTUALLY CERTAIN - 95-100%
VERY LIKELY       - 80-95%
LIKELY            - 60-80%
CHANCE            - 30-60%
VERY UNLIKELY     - 20% OR LESS

&&

.MARINE...12/200 PM...

NORTHWEST WINDS WILL INCREASE AND SMALL CRAFT ADVISORY CONDITIONS
ARE LIKELY FROM PIEDRAS BLANCAS TO POINT SAL 10-60 NM AND FROM
POINT SAL TO SANTA BARBARA ISLAND EACH AFTERNOON THROUGH SUNDAY.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEA CONDITIONS WITH SWELLS
OVER 10 FT IS LIKELY FROM PIEDRAS BLANCAS TO SAN CLEMENTE ISLAND
EXCLUDING THE INNER BASINS SOUTH OF POINT CONCEPTION THROUGH
SUNDAY. THERE IS A CHANCE SWELLS WILL BUILD TO NEAR 10 FEET IN THE
SANTA BARBARA BASIN TONIGHT. NORTHEAST WINDS WILL LIKELY DEVELOP
FROM VENTURA TO SANTA MONICA SUNDAY MORNING AND AGAIN EARLY MONDAY
MORNING. THE NORTHEAST WILL LIKELY CREATE SCA CONDITIONS MONDAY
MORNING AND THERE IS A LOW CHANCE SUNDAY MORNING.



&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...HIGH SURF ADVISORY IN EFFECT UNTIL 9 AM PST SUNDAY FOR ZONES
      34-35. (SEE LAXCFWLOX).
     BEACH HAZARDS STATEMENT IN EFFECT THROUGH SUNDAY MORNING FOR
      ZONE 39. (SEE LAXCFWLOX).
     HIGH SURF ADVISORY IN EFFECT UNTIL NOON PST SUNDAY FOR ZONES
      40-41-87. (SEE LAXCFWLOX).
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS IN EFFECT UNTIL 9 PM
      PST SUNDAY FOR ZONE 645. (SEE LAXMWWLOX).
     SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PST MONDAY FOR
      ZONES 670-673-676. (SEE LAXMWWLOX).

&&

$$

PUBLIC...THOMPSON
AVIATION...30
MARINE...30
SYNOPSIS...SETO

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.