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[Printable]
349
FXUS66 KLOX 280306
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
800 PM PDT SUN JUL 27 2014

.SYNOPSIS...
MONSOONAL MOISTURE WILL CONTINUE TO BRING A SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS TO MUCH OF SOUTHWEST CALIFORNIA THROUGH MONDAY.
OTHERWISE...HIGH PRESSURE JUST TO THE EAST OF THE REGION WILL KEEP
TEMPERATURES GENERALLY ABOVE NORMAL THROUGH THE WEEK. NIGHT THROUGH
MORNING LOW CLOUDS AND FOG WILL REMAIN CONFINED MOSTLY TO THE
COASTAL PLAIN.

&&

.SHORT TERM (TONIGHT-WED)...
A GOOD SURGE OF MONSOONAL MOISTURE MOVED INTO SOUTHWEST CALIFORNIA
TODAY...AS EVIDENT BY THE BLENDED PRECIPITABLE WATER PRODUCT SHOWING
VALUES BETWEEN 1.3 AND 1.5 INCHES FOR AREAS SOUTH OF POINT
CONCEPTION. AN UPPER LEVEL WAVE COMBINED WITH SOME ELEVATED INSTABILITY
INTERACTED WITH THIS MOISTURE TO TRIGGER THE AREA OF THUNDERSTORMS THAT
WE SAW EARLIER TODAY ACROSS PORTIONS OF THE LOS ANGELES BASIN AND
CATALINA ISLAND. THE THUNDERSTORM ACTIVITY DIMINISHED ACROSS OUR FORECAST
AREA LATE THIS AFTERNOON...HOWEVER THERE REMAINS CONVECTION TO OUR
EAST. AS OF 745 PM...DOPPLER RADAR SHOWED A CLUSTER OF STORM ACTIVITY
ALONG INTERSTATE 15 BETWEEN VICTORVILLE AND BARSTOW THAT CONTINUES TO
TRACK SLOWLY WESTWARD TOWARDS LOS ANGELES COUNTY. THERE IS STILL A
SLIGHT CHANCE THAT THESE STORMS COULD DRIFT INTO PORTIONS OF LOS
ANGELES COUNTY THIS EVENING...OTHERWISE HAVE REMOVED ANY
THUNDERSTORM THREAT FOR REMAINING PORTION OF THE FORECAST AREA THIS
EVENING.

00Z NAM MODEL SHOWING AREA OF MID LEVEL MOISTURE INCREASING OVERNIGHT
INTO MONDAY MORNING ACROSS MUCH OF THE FORECAST AREA. THIS
INCREASING MOISTURE COMBINED WITH MARGINAL MID LEVEL INSTABILITY ENOUGH
TO WARRANT A 20 PERCENT CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS
MUCH OF THE FORECAST AREA. THE NAM IS KEYING IN ON TWO UPPER LEVEL
WAVES THAT COULD AID IN CONVECTION. THE FIRST IS A WAVE THAT
SETS UP ACROSS THE LOS ANGELES/SAN BERNARDINO COUNTY BORDER
OVERNIGHT. AND THE SECOND IS A WAVE THAT COMES UP FROM THE SOUTH
ON MONDAY MORNING ACROSS THE CHANNEL ISLANDS...POTENTIALLY IMPACTING
THE VENTURA COAST AND SANTA BARBARA SOUTH COAST.

ATMOSPHERE WILL BEGIN TO DRY OUT ON TUESDAY...HOWEVER VERY WARM CONDITIONS
WILL CONTINUE ACROSS INLAND AREAS INTO MIDWEEK.

.LONG TERM (THU-SUN)...BROAD LONG WAVE RIDGE OF HIGH PRESSURE IS
EXPECTED TO PERSIST OVER THE AREA THROUGH THE PERIOD. LATEST
GUIDANCE INDICATED A PV CENTER MOVING NORTH OVER THE AREA FRIDAY
THROUGH SATURDAY. GUIDANCE DIFFERED FROM PREVIOUS RUNS AND WAS
CONSISTENT BETWEEN SUITES. HAVE NOT INCLUDED POPS DUE TO THE DRY AIR
MASS AND SOUTHWEST FLOW. TEMPERATURES WILL DIFFER LITTLE FROM DAY TO
DAY THROUGH THE PERIOD AND LIKELY REMAIN A FEW DEGREES ABOVE NORMAL
WELL INLAND AND AROUND NORMAL ELSEWHERE.


&&

.AVIATION...26/1800Z.

MID/UPPER LEVEL RIDGE OF HIGH PRESSURE OVER THE AREA WILL PERSIST.
OTHERWISE A TROUGH OF LOW PRESSURE OFF SOUTHERN BAJA WILL MOVE NORTH
AND APPROACH THE AREA. UPPER LEVEL LIGHT TO MODERATE SOUTH WINDS
WILL PREVAIL WHILE MID LEVEL LIGHT SOUTH WINDS BECOME MODERATE
BETWEEN 27/06-27/18Z OVER THE AREA. ISOLATED HIGH BASED
THUNDERSTORMS ARE POSSIBLE OVER THE HIGHER TERRAIN AND DESERT
BETWEEN 26/20-27/03Z. THUNDERSTORMS WILL MOVE NORTH APPROXIMATELY
20KT. ISOLATED THUNDERSTORMS ARE POSSIBLE OVER THE COASTAL WATERS
BETWEEN 27/06-27/17Z AND STORMS WILL NORTH 10-15KT. WEAK TO MODERATE
ONSHORE PRESSURE GRADIENT THROUGH 27/03Z AND AFTER 27/20Z OTHERWISE
WEAK ONSHORE GRADIENT. MARINE LAYER CLOUD TOP WAS APPROXIMATELY 1KFT
THIS MORNING AND WILL DIFFER BY PLUS .3KFT SUNDAY MORNING.

KLAX...CIGS 005 AT TIMES THROUGH 26/20Z THEN CHANCE CIGS 004 BETWEEN
27/03-27/14Z AND CIGS 007 BETWEEN 27/14-27/17Z.

KBUR...CURRENT SKY/VSBY CONDITIONS LIKELY THROUGH 27/11Z THEN CHANCE
VSBY 5SM HZ. VERY UNLIKELY MARINE CLOUDS WILL MOVE OVER THE AREA BUT
INCREASING CHANCE AFTER 27/11Z.

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

&&

.MARINE...

27/800 PM

A SLIGHT CHANCE OF THUNDERSTORMS ACROSS THE COASTAL WATERS THROUGH
MIDDAY MONDAY... WITH THE GREATEST PROBABILITY IN THE SOUTHERN
WATERS. OTHER THAN NEAR SHOWERS AND THUNDERSTORMS...WEAK TO LOCALLY
MODERATE WINDS ARE EXPECTED ACROSS THE COASTAL WATERS INTO NEXT WEEK.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
NONE.

$$

PUBLIC...GOMBERG/30
AVIATION/MARINE...KJ
SYNOPSIS...GOMBERG

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