Small Craft Advisory 85, NWS Los Angeles, CA

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
155 PM PDT TUE JUL 1 2014

.SYNOPSIS...

A TROUGH OF LOW PRESSURE WILL BRING CONTINUED OVERNIGHT LOW CLOUDS
AND FOG THROUGH AT LEAST FRIDAY...WITH TEMPERATURES BELOW NORMAL FOR
THE COAST AND VALLEYS AND ABOVE NORMAL IN THE INTERIOR. HIGH
PRESSURE WILL BUILD OVER THE WEEKEND AND THE MARINE LAYER MAY LESSEN
ALONG THE BEACHES...WITH ONLY MINOR TEMPERATURE CHANGES.

&&

.SHORT TERM (TODAY-FRI)...

LOW CLOUDS HAVE HELD STRONG ALONG THE COAST THROUGH EARLY THIS
AFTERNOON AS EXPECTED DUE TO STRONG ONSHORE FLOW AND A SHARP MARINE
LAYER INVERSION. LAX-DAG CURRENTLY SITS AT ABOUT +6MB AND WILL
STRENGTHEN TO ABOUT +8MB THIS AFTERNOON. AS A RESULT GUSTY WINDS ARE
EXPECTED TO CONTINUE FOR THE MOUNTAINS AND ANTELOPE VALLEY THROUGH
THIS EVENING...BUT WILL REMAIN BELOW ADVISORY LEVELS.

NOT A LOT OF EXCITEMENT IN THE SHORT-TERM. CURRENTLY THE LONG-WAVE
RIDGE AXIS IS JUST EAST OF THE AREA...WITH A BROAD TROUGH OF LOW
PRESSURE APPROACHING FROM THE WEST. ON WEDNESDAY...THE TROUGH AXIS
WILL BE OVERHEAD...WITH THE UPPER HIGH CENTERED OVER AZ. BY THURSDAY
AND FRIDAY THE WEST COAST TROUGH WEAKENS AND THE UPPER HIGH WILL
START TO EXPAND WEST.

EVEN WITH THE ABOVE MENTIONED TROUGHS AND RIDGES...NOT A LOT OF
TEMPERATURE CHANGE EXPECTED THROUGH FRIDAY...AS 500MB HEIGHTS WILL
HOVER AROUND 590 DAM. LOW CLOUDS AND FOG SHOULD SPREAD WELL INTO THE
VALLEYS TONIGHT/WEDS MORNING AND AGAIN WEDS NIGHT/THURSDAY
MORNING...MUCH LIKE TODAY. THE MARINE LAYER DEPTH MAY START TO
DECREASE BY FRIDAY MORNING AND INTO THE WEEKEND AS THE UPPER HIGH
EXPANDS WEST...MEANING LESS STRATUS FOR THE VALLEY AREAS. GUSTY WINDS
FOR THE MOUNTAINS AND ANTELOPE VALLEY WILL CONTINUE EACH AFTERNOON
AND EVENING THROUGH THURSDAY NIGHT DUE TO STRONG ONSHORE PRESSURE
GRADIENTS. WINDS SHOULD LIGHTEN UP ON FRIDAY AND INTO THE WEEKEND AS
THE UPPER-LEVEL HIGH EXPANDS WEST...CAUSING THE SURFACE PRESSURE
GRADIENTS TO WEAKEN.

.LONG TERM (SAT-TUE)...

SOME MONSOONAL MOISTURE MAY ENTER THE REGION ON SATURDAY AND SUNDAY
AS THE UPPER-LEVEL HIGH BECOMES CENTERED OVER THE FOUR CORNERS
REGION AND SE FLOW DEVELOPS AT MID-LEVELS. THE 12Z RUN OF THE GFS
BRINGS THE MONSOON FRONT (DEFINED AS AN 850 MB DEWPOINT TEMP OF 8
DEGREES C OR GREATER) INTO EASTERN LA COUNTY ON THESE DAYS. IT STILL
SEEMS LIKE A LONG SHOT FOR ANY CONVECTIVE ACTIVITY OVER THE
WEEKEND...BUT IT IS SOMETHING THAT WILL CONTINUE TO BE WATCHED.

STILL NOT A LOT OF CHANGE EXPECTED IN TEMPERATURES FOR THE
LONG-RANGE...AS 500 MB HEIGHTS WILL REMAIN AROUND 590 DAM. THE
MARINE LAYER DEPTH SHOULD CONTINUE TO SHRINK INTO THE WEEKEND WITH
THE EXPANDING UPPER-LEVEL HIGH AND WEAKENING ONSHORE GRADIENTS.
CURRENT FORECAST KEEPS STRATUS MOSTLY OUT OF THE VALLEYS FOR THE
WEEKEND AND EARLY NEXT WEEK...WITH CONTINUED NIGHT THROUGH MORNING
LOW CLOUDS AND FOG FOR MOST COASTAL ZONES. HOWEVER...WOULD NOT BE
SUPRISED IF COASTAL STRATUS IS MORE PATCHY THAN CURRENTLY FORECASTED
DUE TO THE SHRINKING MARINE LAYER DEPTH INCREASING HIGH-LEVEL
MOISTURE.

&&

.AVIATION...01/1845Z...MVFR CONDITIONS WILL LINGER UNTIL AT LEAST
20Z AT MOST COASTAL TERMINALS. THERE IS A SLIGHT CHANCE THAT KOXR
COULD SCATTER OUT BRIEFLY BETWEEN 23Z AND 01Z. THERE IS A CHANCE
THAT KSBA COULD REMAIN MVFR THROUGHOUT THE PERIOD. IFR TO MVFR
CONDITIONS WILL SPREAD BACK IN THROUGH 05Z FOR THE COASTAL
TERMINALS...AND INTO VALLEY TERMINALS BY 10Z. THERE IS A CHANCE OF
LIFR TO IFR CONDITIONS AT KPRB BETWEEN 09Z AND 16Z.

KLAX...VFR CONDITIONS ARE EXPECTED THROUGH AT LEAST 20Z...OR AS LATE
AS 21Z. MVFR CONDITIONS WILL REDEVELOP BETWEEN 02Z AND 0330Z...THEN
LOWER TO IFR BETWEEN 05Z AND 09Z. VFR CONDITIONS SHOULD LINGER AGAIN
AT KLAX AGAIN.

KBUR...VFR CONDITIONS ARE EXPECTED THROUGH AT LEAST 06Z...OR AS LATE
AS 09Z...THEN IFR CONDITIONS WILL SPREAD INTO KBUR. THERE IS A 30
PERCENT CHANCE OF LIFR CONDITIONS BETWEEN 09Z AND 16Z.

&&

.MARINE...01/900 AM

HIGH CONFIDENCE EXISTS IN THE PACKAGE THROUGH TODAY. MAINLY LIGHT TO
LOCALLY MODERATE WINDS WILL OCCUR THROUGH THIS EVENING. WEAKENING
SURFACE HIGH PRESSURE OVER THE EASTERN PACFIC OCEAN TODAY WILL
STRENGTHEN BETWEEN TONIGHT AND THURSDAY. WINDS WILL BEGIN TO
INCREASE FROM THE NORTHWEST WITH GUSTS OF 25 TO 30 KNOTS EXPECTED
OVER THE OUTER WATERS BETWEEN WEDNESDAY AFTERNOON AND INDEPENDENCE.
THERE IS A CHANCE THAT A SMALL CRAFT ADVISORY FOR THE NORTHERN INNER
WATERS EACH AFTERNOON AND EVENING BETWEEN WEDNESDAY AND FRIDAY.

A LONG-PERIOD SOUTHERLY SWELL FROM A STORM SYSTEM IN THE SOUTHERN
HEMISPHERE...NEAR 62S AND 91W WILL MOVE NORTH AND LIKELY IMPACT THE
COASTAL WATERS AND ADJACENT BEACHES BETWEEN INDEPENDENCE DAY AND
SUNDAY. A HIGH RISK OF RIP CURRENT IS POSSIBLE OVER THE HOLIDAY
WEEKEND...AND A HIGH SURF ADVISORY OR BEACH HAZARDS STATEMENT COULD
BE ISSUED AT A LATER TIME.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
BEACH HAZARDS STATEMENT (SEE LAXCFWLOX).

&&

PUBLIC...SUKUP
AVIATION/MARINE...HALL
SYNOPSIS...BARTLING

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