Forecast Discussions mentioning ACARS, received at FSL on 04/26/01

FOG AND LOW CLOUDS OVER THE STRAIT JDF AND SW INTERIOR ARE BURNING OFF RAPIDLY...SO SUNNY WARM DAY STILL LOOKS GOOD. 850 MB TEMPS PER ACARS SOUNDING 9.5C WHICH FITS WITH NEW 12Z AVN. WL NUDGE UP MAXES TODAY A BIT...ESPECIALLY TO SHOW WARMER TEMPS EAST OF PGTSND.

CONVECTION OVER CASCADES THIS AFTN/EVENING IS STILL A DECENT BET. UPR TROF PROVIDING THE MAIN FORCING SHOWS UP BEST AT 700 MB ON MDLS...BUT IS HARD TO FIND ON IR SATELLITE IMAGERY OFF THE CA/OREGON CST. THERE IS ALSO A BIT OF 300 MB DIVERGENCE FROM THE RIGHT ENTRANCE REGION OF THE JET OVR B.C. CAPES LOOK NR 500 J/KG AT 00Z. SW MID LEVEL FLOW SHOULD FOCUS ANY TSTMS NR THE CASCADE CREST. MOST PROBABLE AREA FOR TSTMS WOULD BE S/CNTRL CASCDS.

MARINE PUSH FOR TONIGHT STILL LOOKS GOOD. NORTHBEND-SEATTLE GRADIENT RISES AFT 00Z TO NR 4 MB ON MDLS...WITH STRATUS EXTENDING ABT 60NM OFSHR FROM THE CST ATTM. MDLS SHOW THE GRADIENT HOLDING THROUGH 00Z THU AFTN...SO NO SIGNIFICANT BREAKOUT EXPECTED THU. LAST COUPLE MDL RUNS HAVE TRENDED A LITTLE SLOWER IN BRINGING IN THE WEAK COLD FRONT (NOW NEAR 135W) ON THU. CURRENT TIMING IS NOW THU AFTN. KICKER UPR TROF 42N/147W IS HANDLED OK BY MDLS SO SOLN ACCEPTED. WL REWORD ZONES TO RESTRICT CHC RAIN TO AFTN PERIOD. HARD TO TELL JUST HOW FAST THE MARINE LAYER WILL ARRIVE...SO FOG VS. DRIZZLE STILL A QUESTION.

REST OF EXTENDED IS STILL ON TRACK WITH AN UPR TROF SETTLING IN OVER THE NE PAC...PUTTING THE SW JET OVR THE PAC NW. SEVERAL IMPULSES LINED UP FOR COOLER WETTER WEATHER. KAM

UIL 126 SEA 013 OLM 013

.SEW...SMALL CRAFT ADVISORY COAST FOR ROUGH BARS. .KATX...VCP31/CSR31...OPERATIONAL



...SYNOPSIS... HIGH PRESSURE WILL WEAKEN ACROSS SOUTHERN CALIFORNIA WITH A GRADUAL COOLING TREND INTO THE WEEKEND. A COASTAL EDDY WILL BRING EXTENSIVE NIGHT AND MORNING LOW CLOUDS AND FOG TO COASTAL AREAS.

...DISCUSSION... MDLS IN GOOD AGREEMENT IN PROGRESSING AN ERN PAC UPR TROUGH INLAND ACROSS THE WRN STATES DURG THE WEEKEND WITH WK UPR TROUGHING LINGERING IN THE VCNTY OF SRN CA EARLY NEXT WEEK.

CSTL CLOUDS...A COASTAL EDDY WL CONTINUE THRU THE WEEKEND. ACARS SOUNDINGS SHOW THE BASE OF A STRONG MARINE INVERSION 800-1000 FT WITH THE TOP AROUND 1200-1500 FT. MINOR DEEPENING SHOULD OCCUR TONIGHT WITH GREATER DEEPENING FRI NIGHT INTO SAT. ADDITIONAL DEEPENING SAT NIGHT INTO SUN WITH PATCHY DRIZZLE POSSIBLE. DENSE FOG IS POSSIBLE THIS MORNING AROUND SUNRISE NR HIGHER CSTL TRRN AND MESAS...LWR CSTL VLYS...AND FAR WRN PORTIONS OF THE INLAND EMPIRE. WITH CSTL EDDY...LOW CLOUDS WL LINGER NR THE BEACHES EACH OF THE NEXT TWO AFTERNOONS.

TEMPERATURES...THE COOLING TREND THAT BEGAN AT THE CST WED WL SPREAD INTO THE LWR CSTL VLYS TODAY AND INLAND VLYS FRI. MINOR COOLING FOR THE MTNS AND DESERTS FOR THE WEEKEND.

SAN 000

.SAN...NONE.

MARTIN



COOLING BEGAN WITH A VENGEANCE WED ACRS THE CSTL PLAIN AS LOW LVL FLOW TURNED ONSHR AND STRATUS FIELD LINGERED NEAR THE COAST ALL DAY. WITH CONTG STRONG ONSHR TRENDS...LOW CLDS AND FOG HAVE SPRD INTO MOST AREAS ON THE CSTL PLAIN. MARINE INVERSION WAS LOW ENOUGH TO CAUSE WDSPRD DENSE FOG...PROMPTING THE ISSUANCE OF DENSE FOG ADVISORIES. DURG THE PAST FEW HOURS...EDDY CRCLN HAS DVLPD...AND MARINE INVERSION WAS BEGINNING TO LIFT RATHER QUICKLY...AT LEAST ACRS SRN SXNS OF THE FCST AREA. ACARS AND RAWS DATA INDICATED THAT INVERSION HAS RISEN TO BETWEEN 1000 AND 1200 FT ACRS L.A./VTU COUNTIES. WL CANCEL DENSE FOG ADVISORY FOR CSTL SXNS OF L.A./VTU COUNTIES...BUT IT STILL LOOKS GOOD ACRS SLO/SBA COUNTIES.

WK S/WV EMBEDDED IN SWLY FLOW ALF APCHG THE FCST AREA AND EDDY CRCLN SHOULD HELP CAUSE ADDITIONAL DEEPENING OF THE MARINE LAYER EARLY THIS A.M.. THEREFORE...XPCT AT LEAST PTCHY LOW CLDS/DENSE FOG TO SPILL INTO THE VLY LOCATIONS OF L.A./VTU COUNTIES BEFORE DAYBREAK. ALSO...COULD BE ENOUGH LIFT FOR SOME PTCHY DRIZZLE IN CSTL SNXS S OF PT CONCEPTION THIS A.M.. 06Z ETA KEEPS EDDY CRCLN ACRS THE INNER WATERS...ALG WITH QUITE A BIT OF MSTR NEAR THE COAST THRU THE AFTERNOON...SO XPCT LOW CLDS TO LINGER NEAR THE BEACHES THRU THE AFTERNOON. INCRSD ONSHR FLOW WL LIKELY CAUSE ADDITIONAL COOLING ACRS THE CSTL PLAIN TODAY...BUT THE MOST SIGNIFICANT COOLING WL BE IN THE VLYS...WHERE SOME LOCATIONS WL LIKELY BE 10 TO 15 DEGS COOLER TODAY THAN ON WED. MTNS AND DSRTS SHOULD ALSO COOL A FEW DEGS TODAY AS THICKNESSES AND H85 TEMPS DROP A BIT.

WK S/WV WL LINGER ACRS THE AREA THRU EARLY FRI...THEN BEGIN TO PULL AWAY. 06Z ETA SHOWS ANOTHER EDDY CRCLN ACRS THE WATERS TONIGHT. XPCT WDSPRD LOW CLDS AND FOG IN CSTL SXNS TONIGHT...WITH AT LEAST AREAS OF LOW CLDS/FOG IN MOST VLY LOCATIONS. 06Z ETA SHOWS A SOMEWHAT WKR AND LESS PERSISTENT EDDY CRCLN ON FRI A.M....AND INDICATES SOMEWHAT BETTER CLRG NEAR THE CST. HWVR...GIVEN THE STG ONSHR FLOW FRI AFTERNOON...WL STICK WITH SLOW CLRG ONCE AGAIN NEAR THE COAST. TEMPS WL CONT TO COOL A BIT MORE IN THE MTNS/DSRTS AND VLYS ON FRI...BUT XPCT LTL CHG ACRS THE CSTL PLAIN.

BROAD TROUGH WL CONT ACRS THE FCST AREA THRU SAT. A RATHER STG S/WV WL PUSH INTO CNTRL CA DURG SAT...CAUSING THE TROUGH ALONG THE W CST TO SHARPEN. THIS SHOULD HELP THE MARINE LAYER DEEPEN FURTHER...WITH LOW CLDS POSSIBLY REACHING THE CSTL SLOPES. IT COULD BE STRONG ENOUGH TO ALLOW FOR ONLY PARTIAL CLRG ACRS MUCH OF THE FCST AREA SAT. TROUGH AXIS WL CROSS NWRN SXNS OF THE FCST AREA SAT EVENING...AND SUBSIDENCE BEHIND IT ALG WITH GOOD NWLY GRADS COULD CAUSE SOME GUSTY NWLY WINDS SBA CNTY SAT EVENING. FARTHER S AND E...DEEP MARINE LAYER SHOULD CONT INTO SUN A.M....AND S/WV MAY PROVIDE SUFFICIENT LIFT FOR SOME DRIZZLE. WARMING SHOULD BEGIN IN MOST AREAS LATER SUN AND MON AS WK UPR LOW DVLPG ACRS THE FCST SAT NIGHT/EARLY SUN DROPS SWD...CAUSING HGTS TO REBOUND AND DRIER NLY FLOW TO SPRD ACRS THE AREA.

LAX 000. BRUNO

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



SAT PIX SHOW A FEW CLOUDS OVER THE UPSTATE OTW SUNNY SKIES IN STORE FOR THE MIDLANDS. SOME LOW LEVEL MOISTURE COULD PRODUCE A FEW CU THIS AFTN AS H5 TEMPS AROUND -20C. WAA WILL NOT BEGIN UNTIL TONIGHT SO CURRENT FCST LOOKS GOOD. ACARS SOUNDING FOR CAE SHOWS H85 TEMPS AROUND 3C, BUT WITH PLENTY OF SUNSHINE WILL EASILY SEE LOWER 70S TDY.

NO CHANGES IN STORE TO CURRENT FCST.

FCSTID = 17 CAE 71 41 81 51 / 0 0 0 0 AGS 73 39 82 49 / 0 0 0 0 SSC 72 41 81 51 / 0 0 0 0 OGB 73 41 82 51 / 0 0 0 0

.CAE... GA...NONE. SC...NONE.