Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 240410
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
910 PM PDT THU OCT 23 2014

.SYNOPSIS...
HIGH PRESSURE BUILDING ALOFT WILL RESULT IN ABOVE NORMAL
TEMPERATURES THROUGH FRIDAY. A WEAKENING COLD FRONT WILL BRING A
SLIGHT CHANCE OF SHOWERS ON THE CENTRAL COAST FOR SATURDAY...ALONG
WITH COOLER CONDITIONS FOR THE REGION THROUGH MONDAY. WARMER WEATHER
IS POSSIBLE FOR THE MIDDLE OF NEXT WEEK.

&&

.SHORT TERM (TONIGHT-SUN)...THE MARINE INVERSION AT LAX EARLY THIS
EVENING WAS ONLY AROUND 500 FT DEEP. MARINE LAYER CLOUDS WERE ABSENT
OVER THE COASTAL WATERS S OF POINT CONCEPTION THIS EVENING. PATCHY
LOW CLOUDS MAY FORM IN THIS AREA OVERNIGHT...BUT SHOULD REMAIN OFF
THE COAST. N OF POINT CONCEPTION...LOW CLOUDS WERE QUICKLY FORMING
ALONG AND OFF THE SLO COUNTY COAST. IT LOOKS LIKE THESE CLOUDS WILL
CONTINUE TO EXPAND OVERNIGHT AND PUSH INTO PARTS OF THE CENTRAL
COAST ALONG WITH PATCHY DENSE FOG. OTHERWISE...SKIES OVER THE
FORECAST AREA ARE EXPECTED TO REMAIN MOSTLY CLEAR THRU THE NIGHT.

AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL LINGER OVER SRN CA THRU
FRI. A LARGE UPPER LEVEL TROF OVER THE E PAC IS EXPECTED TO APPROACH
MAINLY CENTRAL CA FRI NIGHT THEN MOVE INLAND OVER THE AREA ALONG
WITH A DISSIPATING SURFACE COLD FRONT ON SAT. BROAD UPPER LEVEL
TROFFINESS WILL THEN LINGER OVER THE FORECAST AREA SAT NIGHT AND
SUN. IT LOOKS LIKE MARINE LAYER CLOUDINESS WILL BECOME MORE
EXTENSIVE ALONG THE CENTRAL COAST FRI NIGHT INTO SAT...WITH LOW
CLOUDS ALSO EXPECTED FOR SOME COASTAL AREAS S OF POINT CONCEPTION.
CLOUDINESS AND A SLIGHT CHANCE OF SHOWERS ASSOCIATED WITH THE
DISSIPATING COLD FRONT ARE EXPECTED OVER PORTIONS OF SLO/SBA
COUNTIES ON SAT. SOME LOW CLOUDS MAY AFFECT THE L.A./VTU COUNTY
COAST AND ADJACENT VLYS SAT NIGHT INTO SUN MORNING. SOME CLOUDINESS
WILL DEVELOP ON THE N MTN SLOPES SAT NIGHT INTO SUN AS WELL.
OTHERWISE...MOSTLY CLEAR TO PARTLY CLOUDY SKIES SHOULD PREVAIL
ACROSS THE FORECAST AREA THRU SUN. BROAD S TO SW LOW LEVEL FLOW WILL
DEVELOP ACROSS THE REGION ON FRI AND FRI NIGHT...WITH GUSTY WINDS
POSSIBLE ESPECIALLY OVER HIGHER TERRAIN. GOOD ONSHORE FLOW CAN BE
EXPECTED ON SAT...THEN THE FLOW WILL TURN MORE NW TO N OVER MUCH OF
THE AREA SAT NIGHT AND SUN...WITH GUSTY WINDS IN THE MTNS ALONG THE
I-5 CORRIDOR...AND IN THE ANTELOPE VLY. GUSTY NW TO N CANYON WINDS
NEAR ADVISORY LEVELS WILL LIKELY AFFECT THE SBA S COAST AND MTNS SAT
NIGHT AS WELL. IT LOOKS LIKE ONE MORE DAY WITH ABOVE NORMAL TEMPS IN
MANY AREAS ON FRI...THEN TEMPS SHOULD FALL BACK TO NEAR TO SLIGHTLY
ABOVE NORMAL ON SAT...AND TO NEAR TO SLIGHTLY BELOW NORMAL ON SUN.

***FROM PREVIOUS DISCUSSION***

.LONG TERM (MON-THU)...THE TROUGH MOVES OFF TO OUR EAST BY MONDAY
AND TEMPERATURES WILL CREEP UP JUST A BIT ON MONDAY AS A RESULT OF
BUILDING HIGH PRESSURE ALOFT BEHIND THE TROUGH. GFS AND ECMWF DIFFER
AS FAR AS THE FORECAST PLACEMENT OF THE RIDGE AXIS THAT EACH MODEL
BUILDS THROUGH THE REST OF THE FORECAST. EACH FORECAST PEAK RIDGE
HEIGHTS AROUND 588 DM AND ABOUT 586 DM OVER SOCAL...BUT THE GFS PUTS
THE AXIS JUST ABOUT ON TOP OF SOCAL...THE ECMWF KEEPS THE AXIS
FURTHER EAST...WHICH WOULD NOT WARM TEMPS QUITE AS MUCH. THE GFS HAS
SHOWN MORE CONSISTENCY OVER ITS PAST FEW RUNS AND AGREES WELL WITH
ITS ENSEMBLES. THE GFS HAS ALSO TRENDED CONSISTENTLY FROM RUN TO RUN
UP TO ITS LATEST SOLUTION. HIGHS BY WEDNESDAY COULD BE BACK TO THE
MID TO UPPER 80S INLAND VALLEYS.

THE OTHER STORY TO KEEP AN EYE ON IN THE EXTENDED IS THE MODERATE
OFFSHORE FLOW PLUS NIGHTLY OCCURRENCES OF SUNDOWNERS THAT DEVELOP IN
THE GFS AND TO SOME EXTENT EVEN IN THE EC STARTING TUESDAY AND
CONTINUING INTO THURSDAY. THESE WINDS...WITH THE WARMER TEMPS...AND
DRY FUELS...WILL LIKELY BRING SOME FIRE WEATHER CONCERNS TO THE AREA
AND DEPENDING ON HOW LOW RELATIVE HUMIDITIES MAY DROP.

&&

.AVIATION...23/2355Z...THE MARINE LAYER AT KLAX AT 2315Z WAS 550
FEET DEEP AND THE INVERSION TOP WAS AT 2200 FEET WITH A TEMPERATURE
OF 25 DEGREES C.

GENERALLY HIGH CONFIDENCE IN THE 00Z TAFS WITH VFR CONDITIONS
EXPECTED AT NEARLY ALL THE AIRFIELDS THRU FRI. ONLY EXCEPTIONS ARE
AT KSBP WHERE A BRIEF PERIOD OF MVFR VSBYS CAN BE EXPECTED FROM
13Z-17Z...AND AT KSMX WHERE THERE IS A 50-60 PERCENT CHANCE OF LOW
CLOUDS AND LIFR CIGS 10Z-17Z. OTHERWISE...VFR CONDITIONS CAN ALSO BE
EXPECTED AT THESE AIRFIELDS THRU FRI.

KLAX...HI CONFIDENCE IN THE 00Z TAF WITH VFR CONDITIONS EXPECTED
THRU FRI EVENING.

KBUR...HI CONFIDENCE IN THE 00Z TAF WITH VFR CONDITIONS EXPECTED
THRU FRI AFTERNOON.

&&

.MARINE...23/800 PM...

IT IS LIKELY NORTH WINDS WILL DEVELOP NEAR SHORE SUNDAY AND THERE IS
A CHANCE GALES WILL EXIST FROM POINT PIEDRAS BLANCAS TO POINT SAL
10-60NM AND FROM POINT SAL TO SAN CLEMENTE ISLAND SUNDAY THROUGH
SUNDAY NIGHT. A LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP 800 NM
WEST OF THE CENTRAL COAST THIS EVENING AND DEEPEN WHILE MOVING
NORTHEAST FRIDAY THROUGH SATURDAY. SWELLS FROM A FETCH WITH LIMITED
LENGTH AND SHORT-LIVED AND ORIENTED 300-310 DEGREES TO SOUTHWEST
CALIFORNIA WILL CREATE SCA CONDITIONS FOR HAZARDOUS SEAS SATURDAY
NIGHT AND LATER COMBINE WITH LOCALLY GENERATED SEAS SUNDAY AND
CREATE HAZARDOUS SEAS THROUGH MONDAY.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
MARINE WEATHER STATEMENT (SEE LAXMWSLOX).

&&

$$

PUBLIC...SIRARD/JACKSON
AVIATION...SIRARD
MARINE...30/SIRARD
SYNOPSIS...SS

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