Forecast Discussions mentioning ACARS, received at FSL on 05/17/99

A PATCH OF HIGH CLOUDS MOVING OVER PARTS OF THE DISTRICT THIS EVENING...OTHERWISE SKIES CLEAR EVERYWHERE. LOW CLOUDS WELL OFF THE COAST WITH NO REAL SIGNS OF MOVING BACK TOWARD THE DISTRICT EXCEPT PERHAPS ALONG THE CENTRAL COAST REGION. ONLY WEATHER PROBLEM OF IMMEDIATE CONCERN IS GUSTY WINDS ALONG THE SOUTH COAST OF SBA COUNTY WHERE A WIND ADVISORY IS IN EFFECT UNTIL MIDNIGHT. SBA-SMX GRADIENT AT 9 PM WAS -4.3 MB. LATEST WINDS FROM LAS FLORES CANYON WAS NORTH AT 31 GUSTING TO 38 MPH. THIS IS A PRIMARILY GRADIENT DRIVEN WIND EVENT AS UPPER SUPPORT NOT THAT SIGNIFICANT. LATEST KVBX VAD WIND PROFILE SHOWS WINDS TURNING EASTERLY ABOVE 3000 FEET. WINDS SHOULD BEGIN TO DIE DOWN IN ADVISORY AREA AROUND MIDNIGHT.

MARINE INVERSION HAS SHRUNK A BIT DURING THE LAST 24 HOURS. A SIGNIFICANT WARMING HAS TAKEN PLACE ABOVE 1000 TO 1500 FEET OVER THE REGION. LATEST ACARS SOUNDINGS FROM LAX AND THE USC PROFILER SHOW THE MARINE INVERSION DOWN TO NEAR 1200 FEET THERE. 00Z VBG SOUNDING SHOWS INVERSION DOWN TO 1000 FEET WITH SIGNIFICANT WARMING AT MOST LEVELS FROM 24 HOURS AGO. THE CURRENT SOUNDINGS WOULD SUGGEST A VERY WARM DAY IN STORE FOR MONDAY ESPECIALLY AWAY FROM THE COAST. BOTH THE ETA AND NGM INDICATE LIGHT OFFSHORE GRADIENTS IN THE MORNING AS WELL WITH ADDITIONAL BOUNDARY LAYER WARMING. WILL UPDATE FORECAST TO BOOST TEMPS ESPECIALLY INLAND WHERE SOME LOCATIONS COULD REACH 90 DEGREES. 00Z ETA/NGM IN GENERAL AGREEMENT WITH FLAT RIDGE OVER THE DISTRICT THRU MON THEN A WEAK TROF SLIDES IN FOR TUE. WEAKER ONSHORE GRADIENTS MON AFTERNOON THEN A BIT STRONGER TUE AFTERNOON FOR SOME COOLING.

EXTENDED FORECAST...THROW OUT THE MRF SOLUTION AND GO WITH THE ECMWF. WEAK TROFFINESS AT TIMES. GENERALLY FAIR WEATHER WED THRU FRI WITH COASTAL LOW CLOUDS AND FOG.

LAX 0000. SIRARD

.LAX...WIND ADVISORY...SEE LAXNPWLAX. SMALL CRAFT ADVISORY...SEE LAXCWFLAX.

VARIOUS CONVECTIVE BLOBS CONTINUE TO FLARE UP TO OUR WEST OVER THE LAST 24 HOURS ONLY TO DIE OR SEVERELY WEAKEN AS THEY MOVE INTO OUR FORECAST AREA. IN THIS CONNECTION ACARS SOUNDINGS SHOW SURFACE BASED CONVECTION NOTABLY CAPPED BY 700-800 MB INVERSION AT THIS TIME.

SURFACE DATA AT 1 PM SHOWING PLAINS COLD FRONT THROUGH WESTERN MN TO WAVE IN SOUTHEAST NEBRASKA/NORTH CENTRAL KANSAS. LIFTED INDICES SOUTH OF BOUNDARY IN DOUBLE DIGITS PER LAPS/MAPS. CONTINUING WAVES OF IOWA CONVECTION HAVE ENHANCED/FORMED A FRONTAL BOUNDARY EVIDENT FROM SOUTH OF SUX TO NEAR MLI AND TRAILING INTO OUR AREA WEAKLY. PLENTY OF JUICY AIR WITH 70 DEGREE DEWPOINTS IN SOUTHERN HALF OF AREA.

BIGGEST QUESTION IS LOCATION AND TIMING OF PRECIP THREAT IN THE FIRST PERIOD. MODEL QPFS THEMSELVES FOR 0-6 HOURS DON'T SUGGEST THE ETA HAS MUCH CLUE AND THE NGM IS A WEAK BEST. NEVERTHELESS, WITH NO BIG DIFFERENCES IN INITIALIZATION WILL LEAN TOWARD AVN/ETA SOLUTIONS WHICH ARE FAIRLY SIMILAR AND EXPECTED TO BE SOMEWHAT BETTER REGARDING QPF IN CONVECTION. AS FRONT CONTINUES SLOW EASTWARD PROGRESS APPEARS 850 JET/THETA E RIDGE WILL BOTH PUSH INTO AREA WITH BEST SPEED CONVERGENCE OVER NORTHERN PORTIONS OF FORECAST AREA WHERE GRADIENT ALSO IS STRONGEST. THEREFORE WILL HAVE SOMEWHAT HIGHER POPS FOR THUNDERSTORMS IN NORTH TONIGHT THAN IN CENTRAL.

LATER ON THINGS APPEAR TO GET A LITTLE EASIER, ALTHOUGH MODELS DIFFER PARTICULARLY IN SPEED OF BRING FRONT THROUGH WITH THE ETA AND THE AVIATION ABOUT 12 HOURS AHEAD OF THE NGM BY TUESDAY MORNING AND PREFERRED. IN FACT THESE MODELS ARE A BIT FASTER THAN PREVIOUS RUNS. MODELS ARE FAIRLY CONSISTENT IN PUTTING BEST LIFT AND LOW LEVEL MOISTURE CONVERGENCE AHEAD OF FRONT TOMORROW AFTERNOON AND NIGHT FOR THE MORE CERTAIN PRECIP EVENT WHERE CATEGORICAL OR AT LEAST LIKELY POPS WILL BE WARRANTED. ADDITIONAL FRONTAL WAVE OR TWO LIKELY, NOT NECESSARILY WHEN OR WHERE THE MODELS PLACE THEM BUT WILL LIKELY ENHANCE RAINFALL AMOUNTS ABOVE THE GENERAL 1/2 TO 1 INCH INDICATED BY MANUAL PROGS IN LATEST DAY 2 UPDATED.

WINDS AND SURFACE DEWPOINTS SHOULD KEEP MINS ABOVE MOS TONIGHT AND WITH SOME UNCERTAINTY ABOUT AMOUNT OF SUN WILL TRIM BACK NGM MAXES MOST AREAS MONDAY.

.CHI...NONE.

KAPLAN

LARGE AREA OF LOW CLOUDS NOW PUSHING SWD JUST OFF THE CNTRL CST WL HAVE TO BE WATCHED TODAY...AS THEY EDGE INTO WRN SXNS OF SBA AND SLO COUNTIES. OTHERWISE...SHOULD BE A MOSTLY SUNNY DAY ACRS THE REMAINDER OF THE FCST AREA. NEUTRAL TO WKLY ONSHR GRADS CONT TO TREND OFSHR THIS MORNING. PROFILERS CONT TO SHOW CONSIDERABLE WARMING THROUGHOUT THE LOWEST LAYERS OF THE ATMOS...ESPECIALLY ABV 1000 FT. THESE FACTORS SHOULD LEAD TO NOTICEABLE WARMING TODAY IN MOST AREAS...ESPECIALLY IN THE VLYS.

ALL MODELS AGREE THAT FLAT UPR RIDGE WILL BE REPLACED BY WK...FLAT TROUGH TONIGHT AND TUE...AND ONSHR FLOW WILL BEGIN TO INCREASE AGAIN TUE. LOOKS LIKE LOW CLOUDS WILL RETURN TO THE CENTRAL COAST TONIGHT AND TUE MORNING. LOW CLOUDS MAY DVLP ACRS L.A. CNTY CSTL AREAS AS WELL...WITH 03Z ETA HINTING AT DVLPMNT OF WK EDDY CRCLN. OTHER THAN THOSE AREAS...REMAINDER OF THE FCST AREA IS EXPECTED TO REMAIN MOSTLY CLEAR THROUGH TUE SINCE LOW LVLS HAVE DRIED OUT WELL. SOME COOLING MAY BEGIN NEAR THE CST ON TUE AS ONSHR FLOW BEGINS TO INCRS...BUT HGTS AND H85 TEMPS CHG LTL...AND MARINE INFLUENCE IS EXPECTED TO REMAIN CONFINED TO THE CSTL PLAIN. MORE WDSPRD COOLING WILL LIKELY HOLD OFF UNTIL WED IN MOST AREAS.

ALL MODELS INDICATE THAT BROAD UPR TROUGH ALG W CST WILL AMPLIFY SOMEWHAT WED AND THU. THE MRF CONTS TO BE MOST AGRESSIVE IN DEEPENING THE SYSTEM...SHOWING THE DVLPMNT OF CUT OFF LOW BY THE END OF THE WEEK. ALTHOUGH THIS MAY BE OVERDONE...IT HAS BEEN CONSISTENT FOR A COUPLE OF RUNS NOW...AND BEARS WATCHING. AT THE VERY LEAST...DEEPENING UPR TROUGH AND INCREASING ONSHR FLOW WL LEAD TO A GRADUAL INCRS IN LOW CLD COVERAGE AND DEPTH...AND COOLING ACRS THE FCST AREA LATER THIS WEEK.

LAX 000. BRUNO

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

SAN FRANCISCO AREA/CENTRAL CALIFORNIA COAST FORECAST NATIONAL WEATHER SERVICE SAN FRANCISCO CA 900 AM PDT MON MAY 17 1999

NO UPDATES NEEDED FOR CENTRAL COASTAL ZONES THIS MORNING. EARLY MORNING VISIBLE SATELLITE SHOWS SOLID LAYER OF MARINE ST ALONG ENTIRE COASTLINE EXTENDING INTO THE SF BAY AREA AND LOCALLY INLAND A FEW MILES ELSEWHERE. OAK SOUNDING...FT ORD PROFILER AND AIRCRAFT REPORTS SHOW TOPS AROUND 1300-1500 FEET...INDICATING A MID MORNING BURNOFF TIME. THIS IS ACTUALLY ONE OF THE FEW DAYS THIS SPRING THAT WE HAVE SEEN A UNIFORM MARINE - FAIRLY STRONG SUBSIDENCE INVERSION. LAYER FORMED AS A WEAK UPPER RIDGE PASSED OVER THE AREA YESTERDAY...NOW WELL INLAND WITH UPPER FLOW BECOMING SW AGAIN AHEAD OF ANOTHER UPPER TROF SEEN IN SATELLITE WATER VAPOR IMAGERY...135-140W. TODAY SHOULD BE ANOTHER CLEAR ONE AWAY FROM COAST WITH MILD...SLIGHTLY BELOW MID MAY NORMALS FOR HIGHS WHILE COAST WILL REMAIN COOL UNDER THE MARINE INFLUENCE. E PACIFIC TROF IS FORECAST TO PROGRESS GRADUALLY EWD AND SHARPEN A LITTLE AS IT MOVES INTO NRN CA DURING THE DAY TUE. EXPECT A DEEPENING MARINE LAYER AND STRONGER ONSHORE FLOW PATTERN TONIGHT AHEAD OF TROF FOR MORE LOW CLOUD COVER AND COOLER TEMPERATURES FOR TOMORROW INLAND AREAS. THIS PROCESS IS LIKELY TO CONTINUE INTO WED...AS WELL. WITH COLDER THAN NORMAL WATER ALONG THE CA COAST THIS SPRING...EXPECT TEMPERATURES TO CONTINUE BELOW MODEL TRENDS WITH ANY SEABREEZE INFLUENCE. LITTLE CHANCE FOR DAYTIME TEMPERATURES TO REBOUND UPWARD BEFORE A SCHEDULED STRONGER TROF MOVES INTO NRN CA LATE IN WEEK.

POPS ZERO. MACPHERSON

.SFO...TDA...SCA...PIGEON PT TO PT PIEDRAS BLANCAS.

************************************************************ *** NOTE TO CUSTOMERS OF THIS PRODUCT ***

EFFECTIVE AT 9 AM ON TUESDAY JUNE 15TH 1999...THIS PRODUCT/S COMMUNICATION IDENTIFIERS AND TITLE WILL CHANGE:

OLD NWWS ID NEW NWWS ID OLD WMO ID NEW WMO ID NYCSFDNYC NYCAFDOKX FXUS71 KOKX FXUS61 KOKX ************************************************************

A GOOD DAY FOR THE OLD NWS EMPLOYEE TO LOOK OUT THE WINDOW AND SEE THAT THERE ARE CLOUDS MOVING IN FROM THE SOUTHEAST.

I/VE LOOKED AT THE 00Z MODELS RUNS...THE 03Z ETA RUN AND THE 09Z RUC AND AM UNABLE TO FIND MUCH OF ANY INDICATION OF CLOUDS WHERE THE ATMOSPHERE HAS PLACED THEM THIS MORNING. THE MODELS DUE PICK UP THE RH THIS AFTERNOON.

THE CLOUDS ARE VERY CONSISTENT AT 5000 FT BASED ON SURFACE OBS. 88D VWP DATA FROM THIS REGION SHOWS SE AROUND 15 KT. LOOKING AT ACARS OUT OF THE NYC AREA...SEE VERY LITTLE WIND AND MORE OF A SOUTHERLY FLOW THERE. SO IT APPEARS THAT THE MODEL MASS FIELDS ARE CLOSE TO CORRECT...THE CLOUDS OVER EASTERN LI AND THE ATLANTIC ADVECT INTO CT AND THE REST OF LI THIS AFTERNOON.

WILL GO WITH A MOSTLY CLOUDY ON LI AND A PARTLY SUNNY SKY FOR THE CITY AND REST OF ZONES AS THERE/S PROBABLY EVEN MORE MOISTURE THAT THE MODELS ARE INDICATING IN THIS REGIONS.

WILL LOWER TEMPS A TAD BASED ON CLOUDS.

WILL LEAVE REST OF FCST AS IS.

MARINE: DROPPING THE SCA FOR SEAS. CURRENT ALSN6 AND 44025 SEAS AT 5 FEET AND ON A CONTINUED LOWERING TREND BASED ON NAVY NOGAPS AND ETA BASED WAMS. TIDES RUNNING NEAR ASTRONOMICAL LEVELS AND PRESENT NO PROBLEMS.

UPPER AIR: THE OKX (72501) RAWINSONDE CONTINUES TO REMAIN UNAVAILABLE DUE TO EQUIPMENT FAILURE. RETURN TIME FOR DATA IS UNKNOWN. .NYC...NONE.

TONGUE