Forecast Discussions mentioning ACARS, received at FSL on 03/24/00

...SYNOPSIS... A GULF OF ALASKA STORM WILL MOVE TO A POSITION OFF THE SOUTHERN CALIFORNIA COAST SATURDAY. THE STORM MAY MOVE INLAND ACROSS SOUTHERN CALIFORNIA OR NORTHERN BAJA CALIFORNIA LATE SUNDAY OR SUNDAY NIGHT. FOR SOUTHWEST CALIFORNIA...THE MARINE LAYER WILL GRADUALLY DEEPEN THROUGH SATURDAY WITH INCREASING NIGHT AND MORNING LOW CLOUDS AND FOG. OTHERWISE VARIABLE HIGH CLOUDS AND A GRADUAL COOLING TREND THROUGH SATURDAY WITH A CHANCE OF SHOWERS LATE SUNDAY INTO MONDAY.

...DISCUSSION... MDLS ALL TRENDING FARTHER W WITH THE CLOSED UPE LOW FOR SAT...CLOSER TO THE UKMET POSITION. THIS SHOULD KP RAIN OFSHR THRU AT LEAST SAT AND POSSIBLY MUCH OF SUN. LATEST AVN/ECMWF WOULD BRING SHOWERS INTO SRN SXNS OF SRN CA LATE SUN OR SUN NIGHT INTO MON WITH MAIN IMPACT TO THE S ACROSS NRN AND CNTRL BAJA. WL REMOVE POPS FM ALL ZONES FOR SAT. LATER SHIFTS MAY WANT TO TRIM BACK SOME FOR SUN AS WELL.

EARLY EVENING ACARS SOUNDINGS AND NKX RAOB SHOWED THE MARINE INVERSION STILL FAIRLY LOW...AROUND 1000 FT MSL...WITH ONLY MINOR DEEPENING EXPECTED OVERNIGHT. HAVE ADJUSTED STRATUS WORDING ACCORDINGLY WITH LOCALLY DENSE FOG POSSIBLE IN CSTL ZONES...AND STRATUS REACHING INLAND VALLEYS LATE...IF AT ALL...AND IF SO MOSTLY IN THE FORM OF DENSE FOG.

SAN 0000

.SAN...NONE.

MARTIN

WK UPR TROF JUST OFF THE CNTRL CA COAST THIS EVENING WITH BAND OF HI CLOUDS ASSOCIATED WITH IT MOVING TOWARD THE DISTRICT. AT LOW LEVELS...GOOD ONSHORE GRADIENTS AND DEEPER MARINE LAYER (NEAR 1400 FEET AT VBG...AND NEAR 1000 FEET AT LAX ACCORDING TO ACARS DATA) HAS ALLOWED SOME LOW CLOUDS TO FORM AND MOVE TO SOME COASTAL AREAS...MAINLY NORTH OF POINT CONCEPTION. FOG PRODUCT SHOWS MORE EXTENSIVE LOW CLOUDS JUST OFFSHORE OF LAX/VTU COUNTIES WHICH SHOULD MOVE INTO THE COAST AND VALLEYS OVERNIGHT.

00Z MODELS SHOW FAIRLY BENIGN WEATHER OVER THE DISTRICT THROUGH FRI NITE AS A WEAK UPPER TROF LINGERS OFF THE COAST THEN WEAKENS FARTHER FRIDAY NITE INTO SATURDAY AS ANOTHER UPPER TROF DIGS SOUTH INTO AN UPPER LOW SOMEWHERE OFF THE SOCAL COAST BY SAT AFTERNOON. BY LATE SAT AFTERNOON...ETA WEAKEST AND FARTHEST SOUTH AND WEST WITH UPPER LOW... AVN STRONGEST AND MORE NORTH AND EAST (CLOSER TO THE COAST)...WITH NGM IN BETWEEN. EVEN SO...BY 12Z SUN...AVN POSITION WELL SOUTH OF PREVIOUS RUN. THIS TREND PRETTY CLOSE TO THE 12Z ECMWF AS WELL. AT THIS POINT... IT APPEARS THAT THE CHANCES OF PCPN OVER THE DISTRICT SAT WILL BE PRETTY SMALL. AVN/MRF HAVE BEEN CONSISTENTLY PUSHING THE SYSTEM OFFSHORE FROM RUN TO RUN...SO ENOUGH OF A DEGREE OF CONFIDENCE TO DROP POPS ENTIRELY FOR SAT SOUTH OF POINT CONCEPTION...AND KEEP JUST A 30 PERCENT POP OVER NRN SBA COUNTY AND SLO COUNTY. OTHERWISE...REMAINDER OF FORECAST LOOKS GOOD. LOOK FOR A ZONE UPDATE BY 930 PM.

FOR THE EXTENDED...MAY HAVE TO SCALE BACK CHANCE OF RAIN FOR SAT NIGHT AND SUN...ESPECIALLY FOR NORTHERN AREAS GIVEN LATEST AVN RUN. MON LOOKS DRY AND SEASONABLE...THEN ANOTHER SYSTEM MAY AFFECT THE REGION TUE BUT STILL SOME UNCERTAINTY ABOUT THIS.

LAX 0000. SIRARD

.LAX...SMALL CRAFT ADVISORY (LAXCWFLAX).



SATELLITE PICTURES SHOW CLOUD TOP TEMPERATURES IN SYSTEM OFFSHORE NEAR 138W WARMING INDICATING SYSTEM ALREADY BEGINNING TO WEAKEN. SPLIT BECOMING MORE EVIDENT AS PARENT LOW OF THE SYSTEM IS MOVING NE INTO THE ALASKA PANHANDLE WHILE UPPER LEVEL TROUGH BEHIND THE SYSTEM IS DIGGING PUSHING THE SOUTHERN PORTION OF THE SYSTEM TOWARDS CALIFORNIA. A LOT OF LOW LEVEL MOISTURE HANGING AROUND OVER THE INTERIOR SECTIONS EARLY THIS MORNING. WSR-88D VAD WIND PROFILER... ACARS SOUNDINGS...AND TRIP UP TO THE ROOF CONFIRM LIGHT WINDS SURFACE TO 5000 FEET. TOUGH MORNING FOR THE AVIATION FORECASTER. WITH PLENTY OF MOISTURE AND LIGHT FLOW AT THE LOWER LEVELS EXPECT AREAS OF LOW CLOUDS AND FOG TO FORM ESPECIALLY AROUND SUNRISE. WHAT DOES FORM WILL BE SHALLOW AND BURN OFF BY LATE MORNING. SYSTEM WILL CONTINUE TO SPLIT AS IT MOVES EASTWARD WITH MID/HIGH LEVEL CLOUDS MOVING OVER THE AREA LATE TODAY. MODELS ARE PRETTY SIMILAR FOR TONIGHT AND SATURDAY WITH THE SURFACE FRONT DISSIPATING BEFORE IT REACHES THE COAST TOMORROW AND MOST OF THE ENERGY WITH THE SYSTEM MOVING INTO CALIFORNIA. UPPER LEVEL TROUGH SWINGS THROUGH IN THE MORNING WITH UPPER LEVEL RIDGE OUT AHEAD OF THE NEXT SYSTEM BUILDING OFFSHORE BY LATE IN THE DAY. LOTS OF CLOUD COVER OVERNIGHT AND SATURDAY BUT WITH SYSTEM FALLING APART...VERTICAL VELOCITIES VERY WEAK... WILL KEEP POPS JUST IN THE CHANCE CATEGORY.

.EXTENDED...MRF/EURO AND CANADIAN MODELS SIMILAR AND CONSISTENT WITH THE PREVIOUS TWO NIGHTS RUNS. SUNDAY LOOKING A LOT LIKE TODAY. ANOTHER SPLITTING FRONT ON MONDAY BUT SPLIT FURTHER EAST THEN TODAY GIVING THE AREA BETTER CHANCE FOR RAIN. TROUGH DRAGGING THROUGH BEHIND THE FRONT TUESDAY. PROGRESSIVE PATTERN CONTINUES. FELTON

UIL 144 SEA 122 OLM 122

.KATX...VCP21/CSR21...OPERATIONAL. .SEW...SMALL CRAFT ADVISORY COAST FOR HEAVY SWELL. N 

LOTS OF HIGH CLOUDS STREAMING ACROSS THE DISTRICT THIS MORNING...WITH AREAS OF LOW CLOUDS AND FOG OVER THE COASTAL WATERS...BUT ONLY PATCHY LOW STUFF OVER LAND AREAS AT THIS TIME. 00Z NKX SOUNDING AND ACARS DATA SHOWS WEAK INVERSION STILL BLO 1000 FEET ACROSS LA COUNTY...WHILE VBG SOUNDING SHOWS A BETTER INVERSION NEAR 1500 FEET. THIS COMBINED WITH LAX-DAG OFFSHORE TREND WILL KEEP CLOUDS/FOG JUST PATCHY ACROSS LA/VTU COUNTY COASTS THIS MORNING...WITH AREAS ACROSS SBA/SLO COUNTY COASTS. LOOKS LIKE THE LOW CLOUDS WILL KEEP OUT OF THE VALLEYS THIS MORNING. OTHERWISE TODAY LOOKS TO BE RATHER TRANQUIL ACROSS THE DISTRICT WITH VRBL HIGH CLOUDS AND A FEW DEGREES OF COOLING FROM YESTERDAYS HIGHS. TONIGHT EXPECT MARINE LAYER TO DEEPEN SOMEWHAT AS TROFFING GRADUALLY DIGS OFFSHORE...YIELDING WIDESPREAD LOW CLOUDS/FOG FOR THE COASTS AND AREAS FOR THE VALLEYS.

MAIN FORECAST PROBLEM CONTINUES TO BE THE EVOLUTION OF TROF/CUTOFF LOW FORECAST TO DEVELOP OFF THE WEST COAST. MODELS HAVE BEEN TRENDING FURTHER OFFSHORE WITH THIS FEATURE THE LAST COUPLE OF RUNS. 00Z ETA/NGM IN VERY GOOD AGREEMENT KEEPING THE TROF AND ASSOCIATED MOISTURE WELL OFFSHORE...WHILE AVN SHOWS A CLOSED LOW A LITTLE CLOSER TO THE COAST. LATEST UK/CANADIAN MODELS IN GENERAL AGREEMENT WITH ETA/NGM. MODELS ARE FCSTING ATMOS TO REMAIN QUITE DRY AT LOW LEVELS...AND EVEN THE AVN DOES NOT PRODUCE MEASURABLE PRECIP ANYWHERE IN THE FORECAST AREA THROUGH SATURDAY AFTERNOON. WILL DROP REMAINING POPS FOR THE CENTRAL COAST SATURDAY. ELSEWHERE...EXPECT CONSIDERABLE STRATUS/FOG FOR THE COASTS AND VALLEYS SATURDAY MORNING...AND VRBL HIGH CLOUDS THEREAFTER. HIGHS SATURDAY WILL COOL ANOTHER COUPLE OF DEGREES FROM TODAY.

EXTENDED...AVN SOLUTION FOR POSITIONING OF LOW OFFSHORE ON SUNDAY DOUBTFUL AT THIS TIME. UKMET AND CANADIAN MDLS SHOW LOW STILL WELL OFFSHORE BY SUNDAY AFTERNOON...ABOUT 300 MILES WEST OF AVN POSITION. WILL KEEP SLIGHT CHANCE OF SHOWERS GOING FOR SOUTHERN PORTIONS OF THE DISTRICT LATE SAT NIGHT...WITH CHANCE SHRA/TSRA FOR SUNDAY. WILL ALSO ADD SLIGHT CHC FOR MONDAY MORNING EASTERN PORTIONS AS TIMING NOW APPEARS SLOWER. WOULD NOT BE SURPRISED IF LATER SHIFTS HAVE TO ADJUST THIS TIMING FURTHER. ON TUESDAY...MRF NOW LOOKS LIKE AN INSIDE SLIDER...CANADIAN HAS VERY WEAK TROF TO OUR NORTH...BUT UKMET HAS CLOSED LOW DROPPING DOWN ALONG THE COAST...SO WILL MAINTAIN CURRENT CHANCE OF SHOWERS WORDING.

LAX 000. JACOBSON

.LAX...NONE.