Forecast Discussions mentioning ACARS, received at FSL on 04/04/00

SAT PIX AND SFC OBS INDCATED THAT LOW CLDS WERE WDSPRD ACRS CSTL SXNS OF THE FCST AREA EARLY THIS A.M....WITH THE XCPTN OF L.A. CNTY...WHERE INLAND PENETRATION SO FAR HAS BEEN MINIMAL. EDDY-LIKE CRCLN 24 HRS AGO WHICH PRODUCED BROAD SCALE SE-SLY LOW LVL FLOW ACRS THE CSTL WATERS AND FCST AREA HAS BEEN REPLACED BY MORE TYPICAL ONSHR FLOW PATTERN THIS A.M.. DURG THE PAST 24 HRS...ONSHR COMPONENT OF PRES GRADS HAVE INCRSD SIGNIFICANTLY ACRS NRN SNXS...BUT WERE ACTUALLY A BIT WKR ACRS L.A. CNTY...LIKELY EXPLAINING THE FEEBLE PUSH OF LOW CLDS ACRS L.A. BASIN. HWVR...EVEN WITH WK ONSHR FLOW...LOW CLDS SHOULD BECOME WDSPRD IN THE L.A. BASIN THIS A.M.. ACARS DATA AND PROFILERS INDICATE THAT MARINE INVERSION HAS LOWERED A BIT ACRS L.A. CNTY...WITH PROFILERS INDICATING SEVERAL DEGS OF WARMING ABV 1000 FT. THUS...LOW CLDS MAY HAVE TROUBLE SPRDG INTO THE VLYS THIS A.M....AT LEAST ACRS L.A./VTU COUNTIES. ACRS SLO/SBA COUNTIES...INVERSION AND MARINE LAYER HAVE DEEPENED A BIT...BUT REMAINED QUITE LOW. FOG IN A FEW CSTL SXNS WL LIKELY BE DENSE THIS A.M....BUT DO NOT XPCT IT TO BE WDSPRD ENOUGH TO WARRANT ADVISORIES.

ONSHR GRADS WILL INCRS TODAY...AND WITH LOW AND STG INVERSION...CLRG MAY BE SLOW AND LIMITED NEAR THE BEACHES. TEMPS SHOULD LOWER A BIT MORE TODAY ACRS MOST CSTL SXNS AS ONSHR FLOW INCREASES THIS AFTERNOON. HWVR...LOWER INVERSION AND DCRSD MARINE INFLUENCE IN THE VLYS THIS A.M....ESPECIALLY IN L.A. CNTY COULD LEAD TO SOME WARMING TODAY DESPITE INCRSD ONSHR FLOW AND SMALL DECREASES IN THICKNESSES/H85 TEMPS. WITH UPR RDG SLOWLY WKNG AND MOVG E TODAY...MTNS AND DSRTS SHOULD EXPERIENCE SLGT...BUT HARDLY NOTICABLE...COOLING TODAY. 00Z MDLS ARE IN GOOD AGREEMENT WITH OVERALL UPR PATTERN. ALL SHOW THE UPR RDG CONTG TO WKN AND MOV E IN RESPONSE TO A SERIES OF SHORT WAVES PUSHING INTO THE PAC NW. MARINE LAYER SHOULD BEGIN TO DEEPEN TONIGHT AND WED...AND GOOD ONSHR PUSH SHOULD CAUSE INCRSD INLAND PENETRATION TONIGHT. INCRG NWLY LOW LVL FLOW ACRS THE CSTL WATERS TONIGHT AND WED MAY HELP SPIN UP AN EDDY...WHICH WOULD LIKELY ALLOW FOR MORE RAPID DEEPENING OF MARINE LYR. EVEN IF LOW CLDS DO NOT BECOME WDSPRD IN THE VLYS TONIGHT...WHICH IS A POSSIBILITY...MARINE INFLUENCE WL CERTAINLY INCRS THERE...SO XCPT SEVERAL DEGS OF COOLING IN THE VLYS ON WED. XPCT LTL CHANGE IN TEMPS IN MOST CSTL AREAS ON WED...ALTHOUGH MORE NWLY FLOW COULD ACTUALLY LEAD TO WARMING ALONG THE CNTRL CST. MTNS AND DSRTS WL ALSO COOL AS THICKNESSES DROP.

FOR THE EXTENDED...UPR LOW IS PROGGED TO CLOSE OFF NEAR 30N/140W TONIGHT...THEN MOVE LTL THRU FRIDAY A.M.. UPR LOW IS FCST TO BEGIN TO OPEN UP AND LIFT ENEWD LATER FRI INTO SAT...THEN DRIFT ACRS CNTRL AND NRN CA BY SUNDAY. AT THIS TIME...IT APPEARS IT WILL TRACK TOO FAR TO OUR N FOR THREAT OF SHWRS...BUT OF COURSE THINGS COULD CHANGE.

UNTIL THEN...LTL CHANGE IN HGTS AND ONSHR GRADS SUGGEST THAT WEATHER ACRS MUCH OF THE FCST AREA THU WL BE QUITE SIMILAR TO THAT OF WED... WITH NIGHT THRU MORNING LOW CLDS AND FOG IN CSTL SXNS...AND MARINE LYR LIKELY DEEP ENOUGH FOR SOME CLDS TO SPRD INTO THE VLYS. ON FRI...SOME MDLS INDICATE THERE MAY BE ENOUGH RIDGING AHEAD OF THE APCHG UPR LOW TO PRODUCE SOME WARMING AND A DCRSG MARIINE LYR...WHICH WOULD REVERSE SAT AS HGTS BEGIN TO FALL. AT THIS TIME...WL NOT TRY TO FINE TUNE EXTENDED SINCE...AFTER ALL...IT IS BASED UPON THE MOVEMENT OF A CUTOFF LOW.

LAX 000. BRUNO.

.LAX...NONE.



...SYNOPSIS...

A HIGH PRESSURE RIDGE OVER SOUTHERN CALIFORNIA WILL WEAKEN THROUGH WEDNESDAY AS SURFACE LOW PRESSURE DEVELOPS OVER UTAH. ONSHORE FLOW WILL STRENGTHEN...INCREASING THE MARINE LAYER AND NIGHT AND MORNING COASTAL LOW CLOUDS AND FOG. OTHERWISE...SKIES WILL BE FAIR WITH COOLER DAYTIME TEMPERATURES...ESPECIALLY INLAND THROUGH MIDWEEK.

...DISCUSSION...

LOW CLOUDS ARE MAKING PROGRESS THROUGH THE INNER WATERS THIS EVENING. DEWPOINTS HAVE INCREASED A FEW DEGREES OVER LAST NIGHT AND RANGE FROM THE MID TO UPPER 50S. KNKX RAOB SHOWS MULTIPLE INVERSIONS STARTING AROUND 700 FT AND ACARS DATA FROM KLGB SHOWS BASE OF INVERSION NEAR 500 FT.

A FAILURE OF THE LOCAL AWIPS TEXT SERVER HAS MADE IT NECESSARY TO ACCESS MOST OF OUR DATA VIA THE INTERNET. PARTS OF THE ETA AND NGM HAVE POSTED AND CONTINUE TRENDS OF PREVIOUS RUNS...WEAKENING UPPER HIGH AND INCREASING SURFACE ONSHORE FLOW OVER THE NEXT COUPLE OF DAYS. WILL UPDATE FORECAST TO ADD PATCHY DENSE FOG WORDING TO COASTAL ZONES DUE TO LOW INVERSION AND HIGH DEWPOINTS. OTHERWISE...CURRENT FORECAST PACKAGE LOOKS ON TRACK.

SAN 0000

.SAN...NONE. JAD

INITIALIZATION FAVORS OLD AVN WITH CURRENT SATELLITE/PLOT/ACARS. INHERENT STREGTHS OF AVN HANDLING THIS FLOW WELL THUS WILL STICK WITH AVN (OLD OR NEW) WITH PACKAGE. MAIN UPR FLOW CENTERED NR 50N TO ADVECT SERIES OF SHORT WAVES INTO WRN WA OVR NEXT COUPLE DAYS. NXT SHORT WAVE RAPIDLY MOVG INLND LATER THIS EVE -5 MICROBARS/SEC OMEGA AND TIGHT GRADIENT OF ANTICYLONIC VORTICITY ADVECTION FOLLOWING TROF AXIS. XPCT THIS COMBO TO TRANSPORT WINDS ALOFT DOWN TO SFC WITH TROF PASSAGE...WITH WINDY/BREEZY CONDS DEVELOPING. APPLYING THAT TO PACKAGE...MAY NEED TO BUMP UP WINDS ESPECIALLY IN MARINE PACKAGE. AS WELL INSTBY LOOKING HEALTHIER THAN PAST SYSTEMS WITH CONSISTENT INCREASING SPEED/DIRECTIONAL WIND SHEAR FM SFC TO 50H. ALSO, 50H TEMPS DROP 10C IN NEXT 12 HRS TO FURTHER DESTABALIZE AMS. AGAIN, XPCT CONVERGENCE ZONES TO DEVELOP DOWNWIND OF VRISL AND OLYMPICS WITH TROF PASSAGE WITH ENHANCED LIFT IN THOSE REGIONS. WILL ADD CHC TSTORMS TO THOSE AREAS WITH ICE PELLETS TO SHOWERS ELSEWHERE. .XTNDD... NOTHING NEW AT THIS TIME... YET WAREY OF MRF AS HIR LATITUDINAL SPLIT PERSISTS. MRF ALMOST SUGGESTING A REX BLOCK WITH STATIONARY RIDGE OVR AK AND FLOW TRAVERSING S BENEATH THE BLOCK. WILL SPEND MORE TIME WITH THIS LATER... AS PACKAGE LOOKS REASONABLE. QUERCIAGROSSA

UIL 668 SEA 556 OLM 356

.KATX...VCP32/CSR31...OPERATIONAL.

.SEW...SMALL CRAFT ADVISORY COAST...STRAIT...AND ADMIRALTY INLET.

N