Forecast Discussions mentioning ACARS, received at FSL on 06/19/99

...SYNOPSIS... WEAK HIGH PRESSURE WILL CONTINUE ACROSS SOUTHERN CALIFORNIA THROUGH THE WEEKEND WITH SEASONALLY WARM TO HOT TEMPERATURES INLAND AND PERSISTENT LOW CLOUDS AND FOG NEAR THE BEACHES. MODERATE SURF FOR SOUTH AND SOUTHWEST FACING BEACHES THIS WEEKEND AS SWELL FROM A STORM OFF THE COAST OF NEW ZEALAND ARRIVES.

...DISCUSSION... ACARS SOUNDINGS EARLY THIS EVENING SHOWING A DECR IN MARINE LYR DEPTH FM 24 HOURS AGO OF AROUND 500 FT...TO 800 TO 1000 FT FOR THE CSTL PLAIN OF LOS ANGELES AND ORANGE COUNTIES...1200 FT FOR CSTL SAN COUNTY...AND 1800 FT INLAND EMPIRE. NO CSTL EDDY INDICATED THE NEXT TWO NIGHTS WITH A CONTINUATION OF THE WK ONSHR FLOW PATTERN. NUMEROUS MINOR TOUCH UPS TO THE EXISTING PACKAGE...MAINLY FOR ADJUSTING THE CLOUD WORDING FOR CSTL/VLY ZONES AND MINOR ADJUSTMENTS TO TEMPERATURES BASED ON OBSERVED HIGH TEMPERATURES TODAY AND EXPECTED GRADUAL INLAND WARMING THE NEXT TWO DAYS. ONLY TEMPERATURE ADJUSTMENTS OF SIGNIFICANCE WERE TO LOWER MAXES FOR ANAHEIM AND MINS FOR THERMAL. UPR TROUGHING ALG THE PAC NW CST EXTENDING WKLY INTO NRN CA WL MAINTAIN ENOUGH SWLY FLOW ALF OVR SRN CA TO PRECLUDE AN INFLUX OF MONSOONAL MSTR INTO SRN CA THRU THE WEEKEND....THUS...A FEW AFTERNOON CLOUDS OVR THE MTNS AT MOST.

CSTL...SOME LONG PERIOD (20 SECOND) S TO SW SWELL BEGAN ARRIVING THIS AFTERNOON. THIS IS THE INTIAL ARRIVAL OF SWELL FM A STORM THAT WAS OFF THE CST OF NEW ZEALAND DURG THE END OF LAST WEEK. SWELL FOR SRN CA FM THIS STORM SHOULD PK SAT AFTERNOON INTO SUN WITH MDT SURF FOR S AND SW FACING BEACHES.

SAN 0000

.SAN...NONE.

MARTIN

SFC HI PRES SITUATED OVER LWR GRTLKS AT 18Z...PROVIDING LIGHT WINDS AND PLENTY OF SUNSHINE TO NRN IL/NW IND. ACARS SOUNDINGS OUT OF ORD INDICATE SUBSIDENCE INVERSION BASED AT ARND 4 KFT...WITH 875 MB TEMP OF ONLY 8.3 DEG C...SO SFC TEMPS STRUGGLING INTO THE 70S DESPITE STRONG LATE JUNE SUN.

MODELS FAIRLY SIMILAR AND CONSISTENT WITH PAST RUNS IN BUILDING UPR RDG OVR THE HIGH PLAINS THRU 48 HRS. SERIES OF WEAK S/WV TROFS FCST TO RIDE OVER THE TOP OF BUILDING RDG...WEAKENING AS THEY APPROACH IL. MAIN THERMAL AND UPPER JET FORCING REMAINS TO NORTH OF IL THRU SUNDAY. IN ADDITION...AS SFC HIGH PUSHES OFF THE NERN U.S. ATLANTIC COAST...RDG AXIS REMAINS IN PLACE BACK THROUGH GULF STATES INTO TX. THIS WL HELP TO KEEP DRIER AIR IN PLACE ACROSS IL/IND AS MAIN MOISTURE FEED OVR THE WRN PLAINS THRU PD. RESULT IS NO REAL CHC OF SIG PCPN FOR NRN IL/NW IND UNTIL LATE SUN. GRADUAL WARMING TREND OVR THE WEEKEND AS SRLY H85 FLOW GRADUALLY INCREASES WITH RESULTING WAA.

.CHI...NONE

RATZER

...SYNOPSIS... WEAK HIGH PRESSURE WILL CONTINUE ACROSS SOUTHERN CALIFORNIA THROUGH THE WEEKEND WITH SEASONALLY WARM TO HOT TEMPERATURES INLAND AND PERSISTENT LOW CLOUDS AND FOG NEAR THE BEACHES. MODERATE SURF FOR SOUTH AND SOUTHWEST FACING BEACHES THIS WEEKEND AS SWELL FROM A STORM OFF THE COAST OF NEW ZEALAND ARRIVES.

...DISCUSSION... THE INVERSION BASE LOWERED TO AROUND 1000-1200 FEET PER ACARS SOUNDINGS AND 19/00Z KNKX RAOB. THIS HAS KEPT THE LOW CLOUDS OUT OF THE INLAND EMPIRE. BOTH THE MESO-ETA AND COAMPS MODELS CLEAR THE LOW CLOUDS OVER ORANGE/SAN DIEGO COUNTIES BETWEEN 15Z AND 18Z TODAY. CURRENT FORECASTS LOOK GOOD ADVERTISING CLEARING BY MID-MORNING AND A FEW DEGREES WARMER EACH DAY. ONSHORE SURFACE PRESSURE GRADIENTS TODAY AND SUNDAY...AROUND +7 MB KSAN-KTPH...WILL PROVIDE MODERATING SEA BREEZES AND KEEP TEMPERATURES AROUND 70 AT THE COAST WHILE ADVECTING ENOUGH MOISTURE FOR LOW CLOUDS/FOG TO FORM AGAIN AT NIGHT. THE MESO-ETA DERIVED SOUNDINGS CONTINUE SHRINKING THE MARINE LAYER DEPTH TO AROUND 750 FEET BY 20/03Z. WITH THE BASE OF THE INVERSION GETTING CLOSER TO THE TOPS OF THE COASTAL MESAS AND INLAND VALLEY FLOORS...DENSE FOG MAY BE MORE WIDESPREAD TONIGHT. OVER THE INLAND EMPIRE...WITH NO LOW CLOUDS TODAY OR SUNDAY DUE TO LOWERED MARINE LAYER...THE ONLY CHANGE WILL BE SLIGHT INCREASE IN TEMPERATURES EACH DAY BASED ON 1000-850 MB THICKNESS INCREASE OF 10 METERS PER DAY.

FOR NOW THE MOUNTAINS AND DESERTS WILL SHOW LITTLE CHANGE THROUGH SUNDAY SINCE THE EXTENT OF THE MOISTURE SURGE UP THE GULF OF CALIFORNIA AND ACROSS SE CALIFORNIA REMAINS UNCERTAIN. THE NWS MODELS ARE IN GOOD AGREEMENT WITH DEVELOPING AND KEEPING QUASI-STATIONARY A WEAK TROUGH ALONG 125W NORTH OF 35N AND A FOUR CORNERS HIGH AT 500 MB THROUGH SUNDAY AFTERNOON...WHILE MOVING A WEAK INVERTED TROUGH NW ACROSS SONORA AND N BAJA TOWARDS SW CALIFORNIA. HOWEVER THE 850 AND 700 MB PROGS SHOW OSCILLATING WIND DIRECTIONS BETWEEN SOUTHEAST AND SOUTHWEST THROUGH MONDAY. THIS MAY BE DUE TO DIURNAL HEATING OVER THE MODELS TERRAIN. THE 700 MB TROUGH DIGGING SOUTH ALONG 125W TO 28N BY MONDAY AFTERNOON SHOULD SUPPORT A PREDOMINATE SOUTHERLY DIRECTION ACROSS THE UPPER GULF.

SAN 0000

.SAN...NONE.

BALFOUR

SFC PATTERN THIS EVENING IS IN GENERAL...QUITE SIMILAR TO 24 HRS AGO. ACARS DATA...OBSERVATIONS AND PROFILER DATA INDICATE THAT THE MARINE LYR HAS INDEED BECOME MORE SHALLOW DURG THE PAST 24 HRS...WITH THE BASE OF THE INVERSION NOW RUNNING BETWEEN 900 AND 1200 FT. SOME DENSE FOG HAS DVLPD ACRS CSTL SXNS FROM SRN SBA COUNTY SWD THRU L.A. CNTY...AND BASED ON CURRENT THINKING THAT THIS WILL BECOME MORE WDSPRD...HAVE ISSUED DENSE FOG ADVISORY THROUGH 9 AM SAT FOR THOSE AREAS. WITH MORE SHALLOW MARINE LYR...BLV LOW CLDS/FOG WL STAY OUT OF THE VLYS TONIGHT. ANOTHER AREA OF CONCERN IS CLRG PATTERN PUSHING STGLY SWD ALG THE CNTRL CST. THIS MAY KEEP CSTL SXNS OF SLO CNTY FAIRLY CLR TONIGHT/SAT A.M.... ALTHOUGH ATTM FEEL THAT SOME LOW CLDS/FOG WL DVLP IN THAT AREA.

WK UPR RDG WL CONT TO HOLD ACRS THE FCST AREA THRU SUN. HGTS... THICKNESSES...BOUNDARY LYR AND H85 TEMPS WILL CONT TO EDGE UPWARD EACH OF THE NEXT TWO DAYS...FOR CONTD SLGT WARMING EACH OF THE NEXT TWO DAYS IN THE MTNS...DSRTS AND VLYS. CONSIDERABLE WARMING HAS OCURRED ABOVE 1200 FT WHICH HAS CAUSED THE INVERSION TO BECOME VRY STG. THIS ALLOWED TEMPS TO WARM IN THE VLYS TODAY...AND ADDITIONAL SHRINKAGE OF THE MARINE LYR WOULD REMOVE MOST OF THE MARINE INFLUENCE FROM THE INLAND VLYS SAT...FOR A BIT OF EXTRA WARMING IN THOSE AREAS. STG INVERSION AND ONSHR FLOW SHOULD CAUSE LOW CLOUDS TO HANG TOUGH NEAR IMDT CST SAT AFTERNOON. OVERALL WEATHER PATTERN LOOKS VERY SIMILAR ON SUN...SO XCPT VERY SIMILAR WEATHER BOTH WEEKEND DAYS.

OVERALL UPR PATTERN MAY BECOME MORE FAVORABLE FOR SOME TSTM ACTIVITY ACRS THE MTNS AND DSRTS BY EARLY NEXT WEEK AS UPR LVL FLOW BECOMES INCRGLY MOIST. HWVR...LATEST MDLS HAVE TRENDED TOWARD A DRIER MORE STABLE PATTERN FOR THE FCST AREA. OTHRWISE...XPCT SIMILAR WEATHER TO CONT INTO EARLY NEXT WEEK...WITH NIGHT THROUGH MORNING LOW CLOUDS AND FOG NEAR THE COAST ALONG WITH LTL CHG IN TEMPS...WHILE SEASONABLY WARM WEATHER CONTS ACRS INLAND AREAS.

LAX 0000. BRUNO.

.LAX...DENSE FOG ADVISORY...SEE LAXNPWLAX ...SMALL CRAFT ADVISORY...SEE LAXCWFLAX.