SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
AFDLOX 200 PM PDT SAT JUN 12 1999
LATEST SATELLITE/SURFACE OBS INDICATE SUNNY SKIES ACROSS THE
DISTRICT...EXCEPT FOR SOME PESKY STRATUS NEAR THE BEACHES. CURRENT
ACARS SOUNDINGS INDICATE MARINE LAYER HAS SHRUNK DOWN TO AROUND
1000 FEET THIS AFTERNOON.
OVERALL...MODELS CONTINUE IN VERY GOOD AGREEMENT THE NEXT COUPLE OF
DAYS...WITH UPPER RIDGE CONTINUING TO DOMINATE THE WEATHER PICTURE.
H5 HEIGHTS CONTINUE TO INCREASE THIS EVENING AND OVERNIGHT...SO
MARINE LAYER WILL CONTINUE TO SHRINK. IN FACT...SHOULD BE LOW ENOUGH
TO KEEP ALL VALLEY AREAS CLEAR TONIGHT. HOWEVER...WITH SHALLOW MARINE
LAYER CONFINED TO COAST...WILL GET SOME PATCHY DENSE COASTAL FOG FROM
SAN LUIS OBISPO TO LOS ANGELES COUNTIES. FOR SUNDAY NIGHT AND MONDAY
UPPER RIDGE MAINTAINS...SO LITTLE CHANGE EXPECTED IN MARINE LAYER
DEPTH OR COVERAGE. FOR MOUNTAINS/DESERTS AREAS...UPPER RIDGE WILL
KEEP SKIES MOSTLY CLEAR THROUGH MONDAY.
AS FOR TEMPS...LIMITED MARINE LAYER AND CONTINUED THICKNESS INCREASES
WILL ALLOW WARMUP TO CONTINUE THROUGH MONDAY. IN FACT...TEMPS IN THE
UPPER 80S TO MID 90S WILL BE COMMON IN THE VALLEYS SUNDAY AND MONDAY.
ONE SHORT TERM CONCERN IS SUNDOWNERS ACROSS SOUTHERN SANTA BARBARA
COUNTY. CURRENT SBA-SMX GRADIENT IS BIT MORE OFFSHORE THAN FRIDAY
AFTERNOON. ALSO...MODELS INDICATE SOME DECENT LOW LEVEL SUPPORT.
WILL MENTION LOCAL NORTHERLY WINDS FOR ZONES 39/52 TONIGHT. LOOKS
LIKE CONDITIONS WILL REMAIN FAVORABLE FOR SUNDOWNERS SUNDAY AND
MONDAY. GIVEN THE WARM AIRMASS...THE DOWNSLOPE WINDS COULD PUSH TEMPS
ALONG THE SOUTHERN SBA COUNTY COAST TO AROUND 80 DEGREES THE NEXT
COUPLE OF DAYS.
LAX 000. THOMPSON.
.LAX...GALE WARNING/SMALL CRAFT ADVISORY...SEE LAXCWFLAX.
EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
AFDSAN 200 PM PDT SAT JUN 12 1999
...SYNOPSIS...
BUILDING HIGH PRESSURE WILL BRING FAIR WARMER WEATHER THROUGH
MONDAY. A WEAK ONSHORE FLOW WILL BRING LOW CLOUDS AND AREAS OF DENSE
FOG TO THE COAST TONIGHT AND AGAIN SUNDAY NIGHT.
...DISCUSSION...
LOW CLOUDS CLEARED OUT EARLY THIS MORNING AND HAVE PUSHED TO ABOUT
10 TO 12 NM OFF THE COAST...EXCEPT SOME PATCHY LOW CLOUDS OFFSHORE
WEST OF CAMP PENDLETON...THIS AFTERNOON. RECENT ACARS SOUNDINGS FROM
KSNA PUTS THE BASE OF THE MARINE INVERSION AROUND 900 FEET WHICH IS
ABOUT 800 FEET LOWER THAN IT WAS EARLIER THIS MORNING. EXPECT THE
ST/FOG TO RETURN TO THE COAST THIS EVENING BUT IT SHOULD BE MUCH
LOWER AND SHOULD NOT PENETRATE AS FAR INLAND AS IT DID LAST NIGHT.
COULD BE AREAS OF DENSE FOG ALONG THE COAST TONIGHT AND AGAIN SUNDAY
NIGHT.
MODELS IN AGREEMENT BUILDING A RIDGE OVER THE SOUTHWEST THROUGH 48
HOURS. THE MODELS ALSO AGREE THAT A WEAK CUTOFF LOW DEVELOPS
SOMEWHERE OVER NORTHWEST MEXICO...SOUTH OF ARIZONA/NEW MEXICO. THE
CONCERN THIS DEVELOPING LOW WOULD HAVE OVER THE SOUTHWEST WOULD BE
THE INTRODUCTION OF MOISTURE INTO THE MOUNTAINS AND DESERTS.
HOWEVER...A STREAMLINE ANALYSIS OF THE AVN 500 MB WIND FOR MONDAY
MORNING SUGGEST ANY MOISTURE WILL REMAIN SOUTH OF SOUTHERN CALIFORNIA
AT LEAST. THE AVN MODEL SHOWS A 589 HIGH CENTER OVER NORTHEAST
ARIZONA AND THE MAIN RIDGE/HIGH OFFSHORE TO THE SOUTHWEST WITH A 586
LOW OVER CENTRAL BAJA.
MAIN STORY THROUGH MONDAY WILL BE DRY AND WARM OVER THE COAST AND
INLAND AREAS INCLUDING THE MOUNTAINS...AND VERY HOT OVER THE DESERTS
WITH TEMPS APPROACHING THE 112 DEGREE MARK EXPECTED FOR THE
COACHELLA VALLEY AND THE BORREGO AREA ON MONDAY.
MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT KEEPING THE RIDGE OVER
THE SOUTHWEST WITH SLIGHT FLATTENING AS A S/WV OVER THE EASTERN
PACIFIC RIDES NORTHEAST INTO BRITISH COLUMBIA AND THE PACIFIC
NORTHWEST. THIS SHOULD KEEP DRY WARM WEATHER THROUGH THE WEEK.
FORECASTED ASTRONOMICAL HIGH TIDES FOR SAN DIEGO ARE 7 FEET OR
HIGHER THROUGH TUESDAY SO A MWS FOR MINOR TIDAL OVERFLOW THREAT
REMAINS IN EFFECT THROUGH TUESDAY.
SAN 0000
.SAN...MINOR TIDAL OVERFLOW THREAT ORANGE AND SAN DIEGO COUNTY COASTS
SEE LAXMWSSAN
HORTON