Forecast Discussions mentioning ACARS, received at FSL on 03/26/00

SYNOPSIS...A RIDGE OF HIGH PRESSURE ALOFT WILL CONTINUE TO PROVIDE THE AREA WITH WARM WEATHER THROUGH MONDAY. HOWEVER...IT HAS SHIFTED INTO TEXAS WHICH WILL ALLOW PLENTY OF HIGH CLOUDS TO STREAM IN FROM THE SOUTHWEST. MEANWHILE...A STORM SYSTEM ABOUT 700 MILES SOUTHWEST OF SAN DIEGO IS GATHERING SUBTROPICAL MOISTURE AND WILL MOVE ACROSS SOUTHERN ARIZONA ON TUESDAY. IT WILL BRING SHOWERS AND COOLER TEMPERATURES WHICH WILL LINGER INTO WEDNESDAY.

DISCUSSION...IT'S ONE OF THOSE SITUATIONS WHERE IF I UPDATE THE 1ST PERIOD, I'M HAVE TO UPDATE THE REST OF THEM. I DON'T LIKE MAKING SUCH WHOLESALE CHANGES ON AN EVENING UPDATE, BUT CURRENT SATELLITE TRENDS ARE FORCING MY HAND. UPPER LOW HAS CLOSED OFF NEAR 30N/130W AND HAS ALREADY PIVOTED THE SUBTROPICAL JET INTO S AZ. AS A RESULT, THICK CIRRUS IS HEADING THIS WAY WHICH EXTENDS ALL THE WAY DOWN TO 20N. MID CLOUDS ARE ALREADY AS FAR N AS 25N. AS THE UPPER LOW SITS AND SPINS, THE SUBTROPICAL TAP WILL ONLY WIDEN AS GOES PW IMAGERY HAS BEEN SHOWING ALL EVENING. WE'LL BITE THE BULLET AND REWORD CLOUD COVER IN ALL PERIODS. WITH SO MUCH CIRRUS SUN AND THICKENING MID CLOUDS MON, I'M CONCERNED HIGH TEMPS MAY BE A LITTLE WARM. I DON'T WANT TO TOUCH THOSE YET BECAUSE 700MB TEMPS AND HEIGHTS ALSO RISE SLIGHTLY AHEAD OF THE LOW. WE'LL PASS THAT DECISION TO THE MID SHIFT.

00Z MODELS INGESTED LOTS OF CLOUD DRIFT AND ACARS DATA IN THEIR INITIALIZATION. THAT EXPLAINS WHY ETA/NGM ARE IN EXCELLENT AGREEMENT AND WILL HOPEFULLY YIELD A HIGH-CONFIDENCE FORECAST ONCE THE AVN ARRIVES. AGREE WITH PREDECESSOR FOR A VARIETY OF REASONS (AVN'S TYPICAL BIAS TO LIFT THINGS OUT TOO FAST, THE AMOUNT OF COOLING NEEDED TO SATURATE, DRY LOW LEVELS IN PLACE, ETC.) THAT A SLOWER START TO THE PRECIP IS IN ORDER. ONCE IT STARTS RAINING, THOUGH, COMPARISON BETWEEN EXPECTED PRECIP WATER AND THICKNESSES INDICATE HEAVY RAIN POTENTIAL. 1" PRECIP WATER SATURATES WITH A 5640M THICKNESS -- AND IT'S FORECAST TO DROP TO 5520M. 700MB MIXING RATIOS OF 5-6G/KG AND EVEN SOME WEAK UPPER LEVEL JET COUPLING ALSO SUPPORT AVN STORM TOTAL QPF AROUND 1" IN THE CENTRAL/E CWA. I THINK IF THE MODELS ARE GOING TO TREND ANYWHERE, IT WILL BE TOWARD A WARMER SOLUTION. NORMALLY THAT WOULD REDUCE QPF BUT SINCE WE'RE ALREADY TAPPED INTO THE SUBTROPICS, I THINK A WARMER SYSTEM WILL JUST BE ABLE TO CARRY EVEN MORE MOISTURE INTO SE AZ AND STILL SATURATE THE COLUMN. THIS IS MIMICKING A COUPLE OF SYSTEMS AZ HAD IN FEB AND NOV OF '98 WHICH YIELDED LOTS OF QPF BUT ONLY ADVISORY CRITERIA MOUNTAIN SNOW. SNOW LEVELS STILL APPEAR TO BOTTOM OUT AROUND 7KFT, AND THAT'S AT THE TAIL END. PYTLAK

.TWC...NONE.



ACARS AND VAD WINDS NOT SHOWING AS MUCH MOMENTUM IN LOWEST 3 TO 4 THOUSAND FEET AS EXPECTED. 20-30 MPH LOOKS A BIT HIGH FOR SUSTAINED SPEEDS AND WILL LOWER TO 15 TO 25 ALTHOUGH SOME GUSTS TO 35 MPH STILL LIKELY.

KAPLAN

FORECASTS LOOK GOOD SO NO UPDATES PLANNED AT TIME. FIRST VISIBLE SATELLITE IMAGES OF THE MORNING SHOW A BEAUTIFUL DAY ACROSS THE INTERIOR WITH THE TYPICAL STRATUS ALONG THE NORTH COAST. AN AIRCRAFT SOUNDING FROM MURRAY FIELD HERE IN EUREKA SHOWS A WEAK INVERSION THIS MORNING WHICH SHOULD MIX OUT BY THIS AFTN CAUSING THE STRATUS TO BREAK UP. MY ONLY CONCERN IS THE GREAT AMOUNTS OF STRATUS OFFSHORE WHICH MAY PUSH IN WITH THE SEABREEZE THIS AFTN. VERY TOUGH TO FCST...SO WILL MONITOR AND UPDATE IF NEEDED.

REST OF THE FCST LOOKS ON TRACK AS THE RAIN ON MONDAY SHOULD BE CONFINED TO THE EXTREME N AS THE BAROCLINC BAND WILL CONTINUE TO WEAKEN AS IT MOVES E AND NEARLY ALL DYNAMICS STAY N OF THE AREA. POPS CEC 003 EKA 002 UKI 000.

.EKA...NONE.

MRD