Forecast Discussions mentioning ACARS, received at FSL on 03/09/01

DEALING WITH A WEAK CATALINA EDDY THIS MORNING...WHICH ACTUALLY APPEARS TO WANT TO HANG ON FOR THE NEXT COUPLE OF DAYS. GOOD NEWS IS THAT PRESSURE GRADIENTS ARE WEAK ACROSS THE CWA...LEADING TO ONLY A WEAK ONSHORE FLOW. IN ADDITION...VBG SOUNDING AND ACARS SOUNDINGS SHOW ONLY A WEAK INVERSION. SO THE FEELING HERE IS THAT MARINE LAYER SHOULD BURN OFF AROUND MIDDAY FOR THE CENTRAL COAST AND SBA COUNTY. FOG IN SOME OF THE INLAND VALLEYS OF VTU AND LA COUNTIES SHOULD BURN OFF BY LATE MORNING. CURRENT ZONES HAVE THE LOW CLOUDS/FOG HANDLED WELL FOR NOW. WILL UPDATE ZONES A LITTLE LATER THIS MORNING TO FRESHEN THE WORDING.

**UPON FURTHER REVIEW...CURRENT ONSHORE GRADIENT IS STRONGER THAN DEPICTED BY MODELS. LOW CLOUDS ARE SHOWING NO SIGNS OF ERODING...AND ARE ACTUALLY FILLING IN ACROSS VTU/LA COUNTIES. WILL UPDATE TO GO MORE PESSIMISTIC WITH SKY CON ALONG COASTAL AND SOME INTERIOR VALLEY ZONES. AS A RESULT...HIGH TEMPS WILL HAVE TO BE LOWERED.

12Z MODELS BRINGING NEXT SYSTEM FARTHER INLAND...SO WILL BE TAKING A CLOSER LOOK AT ALLOCATION OF POPS FOR THE EARLY WEEKEND. MORE TO COME IN AFTN DISCUSSION.

LAX 000. MOYER.

.LAX...SMALL CRAFT ADVISORY...SEE LAXCWFLAX.



LOW CLDS HAVE PUSHED INTO MOST CSTL AREAS THIS EVENING...AND WITH GOOD ONSHORE PUSH AND A RATHER DEEP MARINE LAYER...WL LIKELY SPRD INTO ALL CSTL AND VLY AREAS TONIGHT. SOUNDINGS AND ACARS DATA SHOW THAT MARINE LAYER WAS BETWEEN 2500 AND 3000 FT DEEP. WK EDDY CRCLN CONTS ACRS THE INNER WATERS THIS EVENING...BUT NOT AS STG AS THAT SEEN LAST EVENING.

WATER VAPOR IMAGERY SHOWED POTENT UPR LOW OVR NRN OREGON THIS EVENING WITH A TROUGH EXTENDING SWD TO JUST OFF THE CST OF CNTRL CA. MODELS ARE IN FAIRLY GOOD AGREEMENT SHOWING THAT A STG VORT...VERY EVIDENT ON SAT IMAGERY DROPPING SWD JUST OFF THE WA CST...WL BEGIN TO PULL THE UPR LOW IN OREGON SWD TONIGHT. AS THE UPR LOW DROPS SWD...THE TROUGH EXTENSION OFF THE CA CST WL SWING INTO THE FCST AREA EARLY FRI A.M.. DECENT VORT ASSOCD WITH THIS TROUGH AS IT MOVES ONSHR WL HELP DEEPEN MARINE LAYER OVERNIGHT...WITH LOW CLDS/FOG LIKELY REACHING CSTL SLOPES. WITH DEPEENING MARINE LYR...DECENT ONSHR FLOW AND CYCLONIC FLOW ALF OVR THE AREA...DRIZZLE IS POSSIBLE JUST ABT ANYWHERE LATER TONIGHT/FRI A.M.... AND WITH TROUGH HANGING ACRS THE AREA...XPCT MANY AREAS TO STAY MOSTLY CLDY THRU THE DAY. THE SRN END OF TROUGH/ASSOCD VORT MAY ALSO PROVIDE ENOUGH LIFT FOR LIGHT MEASURABLE RAIN ACRS SOME AREAS FRI. MAY ADD SLGT CHC TO MANY ZONES WHICH HAVE NO POPS FOR FRI.

UPR LOW IS PROGGED TO CONT TO DROP SWD FRI...REACHING A POSITION JUST N OF SACRAMENTO BY LATE AFTERNOON. UPR CNTR THEN TRACKS ACRS THE SAN JOAQUIN VLY FRI EVENING...REACHING THE ERN DESERTS SAT A.M.. WITH ITS TRACK ENTIRELY OVR LAND...WITH THE UPR LOW ALREADY RATHER STARVED FOR MSTR...IT WILL HAVE TO DRAW LARGELY ON STG DYNAMICS...WHICH IT WILL HAVE...TO PRODUCE PRECIPITATION ACRS THE FCST AREA. STRONG VORT WRAPPING AROUND THE WRN SIDE OF THIS LOW WILL PUSH INTO NWRN SXNS OF THE FCST AREA FRI AFTERNOON...AND ACRS THE REST OF THE FCST AREA FRI NIGHT AND EARLY SAT. ALSO...DECENT HGT FALLS ACRS THE AREA WL ADD TO THE DYNAMICS. THESE FACTORS WILL COMBINE TO BRING A DECENT CHANCE OF SHWRS TO THE FCST AREA LATE FRI INTO EARLY SAT. COULD EVEN BE A TSTM FRI NIGHT AS COLD AIR ALOFT HELPS TO DESTABILIZE THE ATMOS OVER SRN CA. SNOW LVLS WILL DROP SHARPLY LATE FRI AND FRI NIGHT...LOWERING FROM 6000 FEET IN THE AFTERNOON...TO BETWEEN 3000 AND 3500 FEET BY LATE FRIDAY NIGHT. THIS COULD CAUSE SOME TRAVEL PROBLES ON BOTH I5 OVER THE GRAPEVINE AND I15 THRU THE CAJON PASS.

PRECIP AMTS ARE EXPECTED TO BE ON THE LIGHT SIDE ACRS THE FCST AREA... MOSTLY LESS THAN A QUARTER OF AN INCH. SOME HIGHER TOTALS ARE POSSIBLE IN THE MTNS...ESPECIALLY ACRS THE NRN MTNS OF L.A. AND VTU COUNTIES... WHERE AMOUNTS MAY BE SUFFICIENT TO PRODUCE ENOUGH SNOWFALL TO REQUIRE WINTER WEATHER ADVISORIES. NWLY WINDS WILL BEGIN TO INCREASE ACRS THE MTNS FRI AND FRI NIGHT...THEN CONT INTO SAT AS THE UPR SYSTEM PULLS OFF THE E. THE THREAT OF SHOWERS WILL DECREASE SAT MORNING AS THE UPR LOW PULLS AWAY. DVLPG SUBSIDENCE PUSHING ACRS THE AREA ALONG WITH DECENT NLY GRADS SHOULD ALLOW FOR SOME GUSTY WINDS TO SPREAD INTO THE VLYS AND EVEN SOME CSTL SXNS SAT.

SKIES SHOULD BECOME PARTLY CLOUDY BY LATE SAT...BUT WK TROUGH LINGERING JUST TO THE S OF THE FCST AREA SHOULD KEEP SKIES FROM COMPLETELY CLEARING. THEN...A RATHER STG VORT IS PROGGED TO DROP SWD IN THE NLY FLOW ACRS THE WRN STATES...WITH A VERY POSITIVELY TILTED TROUGH SHARPENING UP AS IT PUSHES ACRS THE AREA SUNDAY AFTERNOON...WHICH HELPS TO FORM A WK UPR LOW OFF THE SRN CA CST SUN NIGHT. AT THE VERY LEAST...THIS SHOULD KEEP PLENTY OF CLOUDS ACRS THE FCST AREA ON SUNDAY...AND IT WILL KEEP THE THREAT OF SHOWERS AS WELL. IT APPEARS THAT UPR RIDGE WILL BUILD INTO NRN AND CENTRAL CA MON... AND MAY BRING DRIER AND WARMER WEATHER TO THE FCST BY TUE. WITH THE WAY THAT UPR LOWS HAVE BEEN DRAWN TO SRN CA LIKE A MAGNET FOR THE PAST SEVERAL WEEKS...WL BLV THAT WHEN IT HAPPENS.

LAX 025. BRUNO.

.LAX...GALE WARNING/SMALL CRAFT ADVISORY...SEE LAXCWFLAX.