Forecast Discussions mentioning ACARS, received at FSL on 04/25/00

...SYNOPSIS... HIGH PRESSURE ALOFT WILL DOMINATE THROUGH WEDNESDAY. SOME ONSHORE FLOW AT THE SURFACE WILL BRING SOME LOW CLOUDS AND FOG TO THE COAST...OTHERWISE SKIES WILL BE CLEAR. AT THE COAST...TEMPERATURES WILL BE COOL. ELSEWHERE...TEMPERATURES WILL BE ABOVE NORMAL UNTIL LATE IN THE WEEK WHEN A SYSTEM TO THE NORTH WILL BRING COOLING.

...DISCUSSION... SATELLITE INDICATES THAT SKIES ARE CLEAR THIS EVENING...THOUGH THE FOG PRODUCT INDICATES A FEW LOW CLOUDS DEVELOPING. THE SOUNDING INDICATES ABOUT A 1300 FOOT MARINE LAYER DEPTH...WHICH WOULD GENERALLY PRECLUDE DENSE FOG ALONG THE SAN DIEGO COUNTY COAST...ESPECIALLY GIVEN A VERY WEAK EDDY. LOCAL DENSE FOG WILL STILL BE POSSIBLE IN ORANGE COUNTY...DUE TO A SLIGHTLY LOWER INVERSION UP THERE BASED ON LAX ACARS SOUNDINGS...AND THE SAN DIEGO COUNTY VALLEYS.

NOT A WHOLE LOT WILL CHANGE THROUGH WEDNESDAY AS THE JET STREAM STAYS OVER THE PAC NW/FAR SW CANADA AS WE GET RIDGING DOWN HERE. MOST OF THE TEMP INCREASES AT 850 MB HAVE ALREADY OCCURRED...THOUGH WE COULD ADD ANOTHER 1-2 DEG C TOTAL BY WED. HOWEVER...WITH THE INLAND HEATING WILL COME INCREASES IN THE ONSHORE PRESSURE GRADIENTS. THE ONLY THING THAT MIGHT ALLOW SLIGHT WARMING NEAR THE COAST TUESDAY WILL BE FEWER LOW CLOUDS IN THE MORNING. WEDNESDAY TEMPS SHOULD BE FLAT OR SLIGHTLY LOWER THERE WEDNESDAY.

SOME COOLING SHOULD OCCUR THURSDAY AND ESPECIALLY FRIDAY WITH THE NEXT SYSTEM MOVING IN. IT SHOULD BE A PROGRESSIVE SYSTEM GIVEN THE SPEED OF THE JET UP NORTH AND THE FACT THAT WE ARE NOT IN A HIGH-AMPLITUDE PATTERN RIGHT NOW. THUS...I FAVOR THE ECM OVER THE MRF. PRECIP CHANCES ARE SMALL...THOUGH A DECENT MARINE LAYER SHOULD DEVELOP AROUND THURSDAY.

THE ZONE FORECAST HAS BEEN UPDATED FOR SOME LOW CLOUD AND FOG AND TEMPERATURE ADJUSTMENTS.

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MAXWELL



STRONG UPR LVL RIDGE FM WRN ONTARIO TO WRN IA THIS MORNING WL MOVE SLOWLY SE AND GRDLY WKN THIS FCST PD. SYSTEM WL PROVIDE CLR SKIES ACRS CWA AT LEAST THRU THE NEXT 24HRS. MODELS INDICATE HI LVL MOISTURE ADVCTG INTO THE AREA FM THE NE WED, BUT UPR LVL RH NOT OVERLY IMPRESSIVE SO PRBLY JUST SOME PATCHY CI.

00Z 925MB ANALYSIS SHOWED CAA OCRG OVR AREA. RECENT ACARS AT FWA SUGGESTS ETA HAS GOOD FCST OF 925MB TEMPS WHICH SHD BE 3-5C COOLER ACRS AREA TODAY. WITH A LTL MORE SUNSHINE THAN YDAY, HIGHS IN 60-65 RANGE LOOK GOOD. WK CAA CONTG TONIGHT WITH CLR SKIES AND WEAKER PRES GRADIENT. MINS SHD BE A LTL LWR THAN EARLY THIS MORNING... FWC'S MINS REASONABLE. WITH RDG SLOWLY APCHG AREA WED, LTL CHG XPCD IN MAXES.

ON THURSDAY, WKNG UPR LVL RIDGE EXPECTED TO MOVE SE OF THE AREA WITH S/WV DIGGING SE ACRS NRN IL TO CENTRAL INDIANA. AVN A LTL STRONGER WITH THIS SYSTEM THAN YDAYS MRF, THUS, WL INTRODUCE CHC OF SHOWERS TO THU PORTION OF EFP.

.IWX...NONE.

JT



...SYNOPSIS... WEAK HIGH PRESSURE WILL CONTINUE OVER SOUTHERN CALIFORNIA THROUGH WEDNESDAY WITH A WEAK COASTAL EDDY EACH NIGHT. INLAND TEMPERATURES WILL GRADUALLY WARM THROUGH WEDNESDAY WITH NIGHT AND MORNING LOW CLOUDS AND FOG AT THE COAST. A DEVELOPING UPPER TROUGH OVER THE EASTERN PACIFIC THURSDAY WILL MOVE INLAND ALONG THE WEST COAST FRIDAY AND SATURDAY BRINGING A DEEPER MARINE LAYER TO THE COAST...COOLING FOR ALL AREAS...AND BREEZY CONDITIONS TO THE MOUNTAINS AND DESERTS.

...DISCUSSION... MDL PREFERENCES...IN THE NEAR TERM...ETA IS HANDLING BETTER THE WK SHORTWAVES MOVG INLAND ACROSS CA DURG THE FIRST 24 HOURS RESULTING IN SLIGHTLY LWR HEIGHTS/THICKNESSES/TEMPERATURES FOR SRN CA DURG THE FIRST 24 HOURS OF THE FORECAST. OTHERWISE...MDLS SIMILAR THRU THE FIRST 72 HOURS. IN THE EXTENDED...MRF/ECMWF IN GOOD AGREEMENT AND FOLLOWED THRU SAT. ECMWF/MRF THEN DIVERGE SOMEHWAT WITH ECMWF TAKING WK CLOSED UPR LOW INTO PLAINS WITH MRF FARTHER W OVR AZ WITH WK UPR LOW. MRF WOULD SLOW SLIGHTLY INTERIOR WARMING FOR SRN CA SUN/MON AND PROVIDE SOME SUPPORT FOR LCL OFSHR WINDS.

GRADUAL WARMING TO CONTINUE INLAND TODAY AND WED...THEN COOLING BEGINNING THU AS HEIGHTS AND THICKNESSES LWR AND ONSHR LOW LVL FLOW INCRS. SYNOPTIC SUPPORT FOR A WK CSTL EDDY OF THE NEXT FEW NIGHTS WITH A LTL STRONGER EDDY POSSIBLE THU NIGHT. EARLY MON EVENING ACARS SOUNDINGS FM LAX/LGB/SNA/SAN/ONT SHOWED THE BASE OF THE INVERSION AROUND 800 FT AT THE CST TO 1800 FT INLAND VLYS. 00Z ETA HAD HIGHEST 975MB RH ALG THE CST THIS EARLY MORNING FM SRN LOS ANGELES COUNTY S...IMPLYING AREAS OF LOW CLOUDS LATE TONIGHT ALG THE CSTL STRIP FM SRN LOS ANGELES COUNTY S EXTENDING LCLLY INTO THE SAN COUNTY VLYS. REDUCED RH VALUES FOR TONIGHT/WED MORNING ALG WITH RISING HEIGHTS AND SLIGHTLY LWR MARINE INVERSION IMPLY LATER ARRIVAL...LESSER INLAND PENETRATION...AND EARLIER BURN OFF WED MORNING. ALSO POSSIBILITY OF LCLLY DENSE FOG SAN COUNTY MESAS AND INLAND ORANGE COUNTY CSTL PLAIN THIS MORNING AND AGAIN LATE TONIGHT INTO WED MORNING.

EXTENDED...AS UPR TROUGH MOVES INLAND ALG THE W CST...FALLING HEIGHT/THICKNESSES AND INCR IN ONSHR FLOW WILL BRING A DEEPER MARINE LYR TO CSTL SXNS...COOLING TO ALL AREAS...AND BREEZY CONDITIONS TO THE MTNS AND DESERTS FOR THU THRU SAT WITH A WARMING TREND RETURNING FOR SUN INTO EARLY NEXT WEEK WITH A BRIEF PD OF OFSHR FLOW POSSIBLE.

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MARTIN