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 250355
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
855 PM PDT FRI APR 24 2015

.SYNOPSIS...
A FAST MOVING COLD FRONT WILL BRING SHOWERS MAINLY TO THE CENTRAL
COAST AND NORTH MOUNTAIN SLOPES ON SATURDAY. GUSTY WEST TO NORTHWEST
WINDS ARE EXPECTED IN THE ANTELOPE VALLEY AND THE VENTURA AND LOS
ANGELES MOUNTAINS SATURDAY TO SUNDAY MORNING. A WARMING TREND WILL
FOLLOW INTO NEXT WEEK WITH ABOVE NORMAL TEMPERATURES AND OFFSHORE
BREEZES.

&&

.SHORT TERM (TONIGHT-MON)...THICK MOIST LAYER WITH PLENTY OF CLOUDS
PERSIST OVER VTU/L.A. COUNTIES FROM THE MTNS TO THE COAST THIS
EVENING. THERE WERE ALSO A FEW LIGHT SHOWERS OVER THE L.A. COUNTY
MTNS. SKIES WERE MOSTLY CLEAR OVER SLO/SBA COUNTIES ALTHO HI CLOUDS
WERE QUICKLY APPROACHING THIS AREA. OVERNIGHT...IT LOOKS LIKE LOW
CLOUDS SHOULD FORM ALONG THE CENTRAL COAST AND INTO THE SLO COUNTY
INTERIOR VALLEYS...WHILE THE CLOUDINESS PERSISTS OVER VTU/L.A.
COUNTIES. GUSTY SW WINDS CONTINUE IN THE ANTELOPE VLY THIS EVENING
BUT WERE GENERALLY BELOW ADVISORY LEVELS. IT IS NOT EXPECTED THAT
WINDS WILL INCREASE OVERNIGHT TO ADVISORY LEVELS (SUSTAINED 35
MPH...FREQUENT GUSTS TO 45 MPH)...THEREFORE THE WIND ADVISORY FOR
THIS AREA WILL PROBABLY BE CANCELLED THIS EVENING. SOME GUSTY NW
WINDS LINGER ALONG THE CENTRAL COAST AS WELL...BUT WILL DIMINISH
OVERNIGHT.

AN UPPER LEVEL TROF WILL MOVE INTO NRN CA TONIGHT THEN SLIDE QUICKLY
THRU ERN AND SERN CA ON SAT. UPPER LEVEL RIDGING WILL BUILD OFF THE
CA COAST SAT NIGHT AND SUN...WITH A BROAD NORTHERLY FLOW ALOFT OVER
SRN CA. THE UPPER RIDGE WILL GRADUALLY BUILD INTO CENTRAL AND NRN CA
SUN NIGHT AND MON...WITH A CONTINUED NORTHERLY FLOW ALOFT FOR SRN
CA.

A COLD FRONT IS FORECAST TO MOVE THRU THE AREA ON SAT ALONG WITH
SOME CLOUDS AND SHOWERS. THE BEST CHANCE OF SHOWERS ON SAT WILL BE
OVER SLO/SBA COUNTIES...WITH A CHANCE OF SHOWERS ALSO ON THE N MTN
SLOPES OF VTU/L.A. COUNTIES...WHICH SHOULD LINGER INTO SAT NIGHT.
RAINFALL AMOUNTS OVER SLO/SBA COUNTIES ON SAT SHOULD RANGE FROM
ABOUT 0.10 TO 0.25 INCH. EVEN STRONGER W WINDS ARE EXPECTED FOR THE
ANTELOPE VLY SAT AFTERNOON AND EVENING...AND A HIGH WIND WATCH IS IN
EFFECT FOR THIS AREA. AREAS OF BLOWING DUST WILL BE LIKELY SAT
AFTERNOON FOR THE ANTELOPE VLY WITH THE POTENTIAL FOR SOME
VISIBILITIES TO DROP BELOW ONE HALF MILE AT TIMES. COASTAL AND SOME
VLY AREAS SHOULD ALSO HAVE GUSTY W TO NW WINDS SAT AFTERNOON AND
EARLY EVENING THANKS TO STRONG ONSHORE GRADIENTS...WITH ADVISORY
LEVEL GUSTS POSSIBLE. STRONG AND GUSTY NW TO N WINDS WILL DEVELOP IN
THE L.A./VTU COUNTY MTNS ESPECIALLY ALONG THE I-5 CORRIDOR SAT
EVENING AND LINGER THRU EARLY SUN MORNING...AND HIGH WIND WATCHES
ARE ALSO IN EFFECT FOR THESE AREAS. PLEASE SEE THE LATEST
NON-PRECIPITATION WEATHER MESSAGE FOR MORE DETAILS ON THE HIGH WIND
WATCHES. WITH THE FLOW TURNING MORE NORTHERLY ACROSS THE AREA BY
EARLY SUN...DRIER AIR AND CLEARING SKIES CAN BE EXPECTED THRU THE
DAY ON SUN.

WINDS WILL TURN NE AND BE GUSTY OVER PORTIONS OF VTU/L.A.COUNTIES
LATER SUN NIGHT INTO MON MORNING...ESPECIALLY BELOW AND THRU THE
FAVORED PASSES AND CANYONS. IT LOOKS LIKE WIND ADVISORIES MAY BE
NEEDED BY EARLY MON MORNING FOR THE SANTA MONICA MTNS...VTU COUNTY
VLYS...SANTA CLARITA VLY...AND THE  WESTERN SAN FERNANDO VLY.
OTHERWISE...MOSTLY CLEAR SKIES AND MUCH WARMER TEMPERATURES CAN BE
EXPECTED ON MON ACROSS THE FORECAST AREA.

TEMPS OVER SWRN CA ARE FORECAST TO REMAIN BELOW SEASONAL NORMS ON
SAT. TEMPS WILL THEN WARM TO A FEW DEGREES ABOVE NORMAL FOR MOST
AREAS ON SUN...AND TO MUCH ABOVE NORMAL ON MON...WITH HIGHS
APPROACHING 90 DEGREES IN THE WARMEST VLYS.

***FROM PREVIOUS DISCUSSION***

.LONG TERM (TUE-FRI)...LONG-RANGE MODELS AGREE THAT A LARGE
UPPER-LEVEL RIDGE WILL REMAIN IN PLACE FOR MOST OF TUESDAY. THIS
WILL RESULT IN CONTINUED WELL ABOVE NORMAL TEMPERATURES FOR MUCH OF
THE AREA. MODELS ALSO AGREE THAT THE RIDGE WILL BREAK DOWN AND SHIFT
TO THE EAST ON WEDNESDAY. THERE SHOULD BE AN INCREASE IN ONSHORE
FLOW DURING THIS TIME AS WELL...RESULTING IN SLIGHT COOLING.
TEMPERATURES WILL LIKELY REMAIN WELL ABOVE NORMAL AWAY FROM THE
IMMEDIATE COAST THOUGH. TEMPERATURES SHOULD RETURN TO NEAR NORMAL
FOR THE END OF NEXT WEEK...AS AN UPPER-LEVEL TROUGH DEVELOPS. THERE
WILL LIKELY BE A RETURN OF THE MARINE LAYER AND ASSOCIATED LOW
CLOUDS AND FOG SOMETIME BETWEEN WEDNESDAY AND FRIDAY AS WELL.

&&

.AVIATION...25/0015Z.

AT 2315Z...THE MARINE INVERSION AT KLAX WAS AROUND 6000 FT DEEP. THE
TOP OF THE INVERSION WAS AROUND 7100 FEET WITH A TEMPERATURE OF 6
DEG C.

MODERATE CONFIDENCE OVERALL IN THE 00Z TAFS. THE COASTAL AND VLY
AIRFIELDS ARE EXPECTED TO HAVE PERIODS OF LOW CLOUDS AND MVFR CIGS
MAINLY LATER TONIGHT AND SAT. THERE IS SOME UNCERTAINTY WITH THE
TIMING OF THE ONSET OF THESE CONDITIONS AND THE IMPROVEMENT TO VFR
CIGS AT TIMES...WITH THE TIMING OFF PLUS/MINUS AN HOUR OR TWO. GUSTY
NW WINDS WILL AFFECT KSMX AND KSBP THROUGH EARLY THIS EVENING AND
AGAIN SAT AFTERNOON. GUSTY W WINDS CAN BE EXPECTED SAT AFTERNOON AT
KSBA...KOXR...KLAX AND KLGB...WITH GUSTY S TO SE WINDS AT KBUR AND
KVNY. FOR KWJF AND KPMD...GENERALLY HI CONFIDENCE IN THE 00Z TAFS
WITH VFR CONDITIONS EXPECTED FOR THE MOST PART THRU SAT. STRONG AND
GUSTY W TO SW WINDS WILL PERSIST THRU THE TAF PERIOD...ALTHO WINDS
WILL BE EVEN STRONGER SAT AFTERNOON WITH GUSTS OVER 40 KT AT TIMES.
THESE WINDS SHOULD CAUSE PERIODS OF BLOWING DUST AND REDUCED VSBYS
TO MVFR CAT. THERE WILL ALSO BE A 20 PERCENT CHANCE OF IFR/LIFR
VSBYS IN BLOWING DUST SAT AFTERNOON AS WELL.

KLAX...MODERATE CONFIDENCE OVERALL IN THE 00Z TAF. PERIODS OF LOW
CLOUDS AND MVFR CIGS CAN BE EXPECTED LATER TONIGHT AND SAT. THERE IS
SOME UNCERTAINTY WITH THE TIMING OF THE ONSET OF THESE CONDITIONS
AND THE IMPROVEMENT TO VFR CIGS AT TIMES...WITH THE TIMING OFF
PLUS/MINUS AN HOUR OR TWO. GUSTY W WINDS UP TO 30 KT AT TIMES CAN BE
EXPECTED SAT AFTERNOON INTO THE EVENING.

KBUR...MODERATE CONFIDENCE OVERALL IN THE 00Z TAF. PERIODS OF LOW
CLOUDS AND MVFR CIGS CAN BE EXPECTED THRU EARLY SAT AFTERNOON. THERE
IS SOME UNCERTAINTY WITH THE TIMING OF IMPROVEMENT TO VFR CIGS AT
TIMES...WITH THE TIMING OFF PLUS/MINUS AN HOUR OR TWO. GUSTY S WINDS
CAN BE EXPECTED SAT AFTERNOON AS WELL.

&&

.MARINE...24/900 PM...
GALE WARNING ISSUED FOR THE OUTER WATERS STARTING AT MIDNIGHT
SATURDAY. HIGH CONFIDENCE IN STRONG WINDS AND MODERATE CONFIDENCE IN
TIMING AS STRONG GUSTS MAY BEGIN A FEW HOURS EARLIER. THERE IS A
CHANCE OF GALE FORCE GUSTS OVER THE WESTERN PORTION OF THE NEARSHORE
WATERS...NEAR SANTA CRUZ ISLAND AND SOUTHWARD TO CATALINA ISLAND. IT
IS LIKELY THAT LOCAL GUSTS OF 30 TO 35 KNOTS WILL OCCUR IN THIS AREA
STARTING AROUND 2 PM SATURDAY AND CONTINUING THROUGH LATE SATURDAY
NIGHT. STRONG TO LOCALLY STRONG WINDS WILL PERSIST ACROSS THE
COASTAL WATERS THROUGH SUNDAY EVENING AND THEN WILL DIMINISH
SOMEWHAT BY LATE SUNDAY NIGHT. SHORT PERIOD SEAS WILL GROW TO 10 TO
13 FEET OVER THE OUTER WATERS...AND TO 7 TO 11 FEET OVER THE
NEARSHORE WATERS...SO THAT NAVIGATION WILL BE EXTREMELY HAZARDOUS
SATURDAY EVENING INTO SUNDAY.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH (SEE LAXNPWLOX).
WIND ADVISORY (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
GALE WARNING (SEE LAXMWWLOX).

&&

$$

PUBLIC...SIRARD/SUKUP
AVIATION...SIRARD
MARINE...SMITH
SYNOPSIS...B

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.