[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 250246
TCDAT3
TROPICAL DEPRESSION LISA DISCUSSION NUMBER  23
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT FRI SEP 24 2004

SHORTWAVE INFRARED IMAGERY AND A RECENT TRMM OVERPASS SHOW THAT THE
CENTER OF LISA REMAINS DISPLACED ABOUT 50 NM TO THE NORTH OF THE
DEEP CONVECTION. CLOUD TOPS HAVE WARMED CONSIDERABLY DURING THE
PAST 6 HOURS AS WELL. DVORAK DATA T NUMBERS REMAIN AT 30 KT FROM
AFWA AND SAB...TAFB IS 35 KT BASED ON A POSITION CLOSER TO THE
CONVECTION. INITIAL INTENSITY WILL REMAIN AT 30 KT FOR THIS
ADVISORY. THE SOUTHEAST QUADRANT OF AN UPPER HIGH CONTINUES TO
PRODUCE 10 TO 20 KT OF SHEAR OVER LISA. HOWEVER...THIS NORTHERLY
SHEAR IS STILL FORECAST TO WEAKEN DURING THE NEXT 24-36 HOURS. THE
OFFICIAL FORECAST CALLS FOR SLOW STRENGTHENING THROUGH 72 HOURS
THEN LEVELS OFF JUST BELOW HURRICANE STRENGTH AS THE TROPICAL
CYCLONE IS EXPECTED TO ENCOUNTER SOUTHWESTERLY SHEAR. THE INTENSITY
FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND FOLLOWS THE SHIPS.

INITIAL MOTION IS 305/7 KT. THE DYNAMICAL MODELS ALL AGREE WITH A
TURN TOWARD THE NORTHWEST AND NORTH DURING THE NEXT 24 TO 48 HOURS
AHEAD OF AN APPROACHING MID/UPPER LEVEL TROUGH FROM THE NORTHWEST.
THE NOGAPS...GFDL...AND THE UKMET ARE NOW INDICATING A SUBTLE TURN
TO THE NORTH-NORTHWEST BY DAY 4 AS A MID LEVEL RIDGE BUILDS IN
BEHIND THE TROUGH. THE OFFICIAL FORECAST FOLLOWS THE PREVIOUS
FORECAST AND IS BASED OFF OF THE GUNA CONSENSUS THAT INCLUDES THE
NOGAPS...GFDL...UKMET AND THE GFS.

FORECASTER ROBERTS/AVILA

FORECAST POSITIONS AND MAX WINDS

INITIAL      25/0300Z 14.3N  44.7W    30 KT
 12HR VT     25/1200Z 15.0N  45.7W    35 KT
 24HR VT     26/0000Z 16.5N  46.7W    40 KT
 36HR VT     26/1200Z 18.2N  47.3W    45 KT
 48HR VT     27/0000Z 20.0N  47.7W    50 KT
 72HR VT     28/0000Z 23.5N  48.0W    60 KT
 96HR VT     29/0000Z 27.0N  48.0W    60 KT
120HR VT     30/0000Z 30.0N  48.0W    60 KT


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