Forecast Discussions mentioning ACARS, received at FSL on 05/11/01

MARINE LAYER THIS EVENING FAIRLY SHALLOW NEAR 1000 FEET AT VBG...AND NEAR 900 FEET AT LAX AND LGB ACCORDING TO ACARS SOUNDINGS. GOOD ONSHORE GRADIENTS CONTINUE THIS EVENING...WHICH SHOULD HELP THE LOW CLOUDS TO MOVE INLAND OVERNIGHT. GENERALLY WEAK WINDS OVER THE COASTAL WATERS NOT CONDUCIVE TO AN EDDY...ALTHOUGH MESO-ETA SUGGESTS A WEAK SE FLOW OVER THE INNER WATERS S OF POINT CONCEPTION LATER TONIGHT...BUT NOT REALLY ASSOCIATED WITH AN EDDY. AT ANY RATE...LOW CLOUDS HAVE BEGUN TO MOVE INLAND OVER VTU COUNTY...BUT ARE RELUCTANT TO DO SO OVER LAX COUNTY. WILL THIS BE ANOTHER NIGHT WHERE STRONG ONSHORE GRADIENTS PRESENT BUT LOW CLOUDS FAIL TO REACH THE L.A. COUNTY VALLEYS LIKE LAST NIGHT? UPPER HEIGHTS LOWER SLIGHTLY OVERNIGHT...BUT SHOULD NOT BE ENOUGH TO SUBSTANTIALLY INCREASE THE MARINE LAYER DEPTH. AM INCLINED TO KEEP AREAS OF LOW CLOUDS OVER THE VALLEYS LATER TONIGHT SINCE MARINE LAYER CAN BE SO TRICKY TO FORECAST IN THESE TRANSITION PERIODS. CENTRAL COAST CLEAR THIS EVENING...BUT WITH LOW CLOUDS ALONG THE S SBA COUNTY COAST...AND LIGHT SOUTHERLY FLOW POSSIBLE OVER COASTAL WATERS N OF POINT CONCEPTION LATER TONIGHT...LOW CLOUDS SHOULD ONCE AGAIN MOVE INTO THE CENTRAL COAST LATER TONIGHT.

UPPER RIDGE OVER SOCAL THIS EVENING WILL BUILD E AND INTO ARIZONA FOR FRI...THEN TO THE FOUR CORNERS SAT. THIS WILL SET UP A MONSOON-LIKE FLOW ALOFT INTO SOCAL FOR SAT. AN UPPER LOW CENTERED NEAR 27N/133W THIS EVENING IS FORECAST TO SLOWLY WEAKEN AND DRIFT OFF TO THE NE TOWARD SOCAL THRU SAT. UPPER LEVEL MOISTURE NOTED WITH THIS FEATURE THIS EVENING. THE MESO-ETA BRINGS IN MID AND UPPER MOISTURE TO THE DISTRICT SAT. LOOKS LIKE DRY WEATHER ALL AREAS THRU FRI NITE...WITH THE USUAL MARINE LAYER CLOUDS ALONG THE COAST AND COASTAL PLAIN NIGHT AND MORNING HOURS. THEN FOR SAT THE UPPER MOISTURE COMBINED WITH THE STRONG MAY SUN AND WEAK UPPER SUPPORT COULD TRIGGER SOME ISOLATED SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS. AFTERNOON TEMPS WILL GRADUALLY COOL DOWN THE NEXT COUPLE OF DAYS AS BOUNDARY LAYER TEMPS/THICKNESSES SLOWLY FALL...AND THE ONSHORE FLOW CONTINUES ALONG WITH A GRADUALLY DEEPENING MARINE LAYER.

WILL DO MINOR ZONE UPDATE BY 915 PM...MAINLY TO ADJUST WORDING IN A FEW ZONES FOR THE FIRST PERIOD. OTHERWISE...CURRENT ZONES LOOK REASONABLE INCLUDING TEMPS.

IN THE EXTENDED...A WEAK UPPER TROF IS EXPECTED TO LINGER OVER THE DISTRICT SUN THRU TUE WHICH WILL RESULT IN LITTLE OVERALL CHANGE IN THE WEATHER OVER THE DISTRICT. TEMPS WILL BE NEAR OR SLIGHTLY ABOVE NORMAL WITH MORE MARINE LAYER CLOUDS NIGHT AND MORNING HOURS FOR COASTAL AREAS. LITTLE MOISTURE IS EXPECTED WITH THE WEAK UPPER TROFFINESS...SO MOUNTAIN CONVECTION SHOULD BE KEPT TO A MINIMUM.

LAX 0000. SIRARD.

.LAX...NONE.



...SYNOPSIS... A WEAK UPPER LOW WILL MOVE ACROSS SOUTHWEST CALIFORNIA SATURDAY BRINGING A SLIGHT CHANCE OF SHOWERS TO THE MOUNTAINS. OTHERWISE... SLOW COOLING WILL CONTINUE INTO SATURDAY...THEN LITTLE CHANGE SUNDAY INTO NEXT WEEK. WEST OF THE MOUNTAINS...NIGHT AND MORNING LOW CLOUDS AND FOG WILL CLEAR TO NEAR THE BEACHES EACH AFTERNOON.

...DISCUSSION... SHORTER RANGE MDLS ARE IN GOOD AGREEMENT IN THE DRAWING THE WK UPR LOW CNTRD NR 17N/132W SLOWLY TOWARD SRN CA DURG THE NEXT THREE DAYS IN RESPONSE TO THE ERN PAC TROUGH ALG 135W MOVG TOWARD THE PAC NW CST. DEEPEST MSTR (MID AND HIGH LVL) WITH THIS SYSTEM WL MOVE ACROSS SW CA SAT BRINGING A SLIGHT CHANCE OF SHOWERS...MAINLY TO HIGHER TERRAIN.

EXTENDED...00Z AVN/MRF HAVE TRENDED STRONGLY TOWARD YESTERDAY'S PREFERRED ECMWF. THIS WL BRING A PROCESSION OF PAC SHORTWAVES INLAND ACROSS THE PAC NW IN FAIRLY FAST...NRLY ZONAL FLOW WITH WK UPR RDGG BUILDING ACROSS SRN CA FM THE PAC.

IN THE NR TERM...THU EVENING ACARS SOUNDINGS SHOWED ONLY MINOR DEEPENING IN THE MARINE LYR FM 24 HOURS AGO WITH LTL CHANGE IN THE STRENGTH OF THE STRONG MARINE INVERSION. ALG THE CST...INVERSION BASES RANGED FM 800-1000 FT LAX/LGB/SNA TO 1200-1400 FT SAN. INVERSION BASES IN THE INLAND VLYS WERE NR 1800 FT. OVERALL...LTL CHANGE IN AREAS TO BE IMPACTED BY CSTL STRATUS THIS MORNING VERSUS THU MORNING.

SAN 000

.SAN...NONE.

MARTIN