[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 260245
TCDAT3
TROPICAL STORM LISA DISCUSSION NUMBER  27
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT SAT SEP 25 2004

SHORTWAVE AND INFRARED IMAGERY DEPICT IMPROVED
ORGANIZATION DURING THE PAST 6 HOURS. THE LOW-LEVEL CIRCULATION
CENTER HAS TUCKED IN FURTHER BENEATH A STRONG BANDING FEATURE
SITUATED OVER THE EASTERN HALF OF THE SYSTEM. DVORAK CURRENT
INTENSITY ESTIMATES ARE 45 KT FROM TAFB AND SAB...AND 35 KT FROM
AFWA.  THE INITIAL INTENSITY IS INCREASED TO 45 KT BASED ON THE
SATELLITE ESTIMATES AND A 2025Z QUIKSCAT OVERPASS WHICH REVEALED A
NUMBER OF REASONABLE 45 KT VECTORS WITHIN THE CONVECTIVE BAND. THE
INTENSITY FORECAST MIRRORS THE SHIPS GUIDANCE AND CALLS FOR SLOW
STRENGTHENING THROUGH THE FORECAST PERIOD...AND BRINGS LISA UP TO
HURRICANE STRENGTH IN 96 HOURS.

THE INITIAL MOTION REMAINS 335/9. LISA IS MOVING WITHIN A WEAKNESS
IN THE SUBTROPICAL RIDGE OVER THE CENTRAL ATLANTIC. ALL OF THE
DYNAMICAL MODELS ARE IN GENERAL AGREEMENT WITH A NORTHWEST TO
NORTH-NORTHWEST MOTION THROUGH 72 HOURS. AFTERWARD...THE MODELS
SPLIT INTO 2 CLUSTERS. THE GFS AND GFDL SHOW A RELATIVELY FAST
MOTION SHOW A TURN TO THE NORTHEAST AFTER DAY 4 IN RESPONSE TO AN
APPROACHING SHORT WAVE TROUGH...WHILE THE NOGAPS...UKMET...FSU
SUPER ENSEMBLE AND THE NAVY GFDN HAVE LISA MISS THE TROUGH AND THEN
INDICATE A TURN TO THE WEST-NORTHWEST AS A MID LEVEL RIDGE BUILDS
IN FROM THE NORTHWEST.  THE OFFICIAL FORECAST PHILOSOPHY IS SIMILAR
TO THE PREVIOUS PACKAGE AND SPLITS THE DIFFERENCE BETWEEN THESE
OPTIONS.

FORECASTER ROBERTS/PASCH

FORECAST POSITIONS AND MAX WINDS

INITIAL      26/0300Z 18.0N  46.2W    45 KT
 12HR VT     26/1200Z 19.1N  46.8W    50 KT
 24HR VT     27/0000Z 20.7N  47.5W    55 KT
 36HR VT     27/1200Z 22.5N  48.2W    60 KT
 48HR VT     28/0000Z 24.3N  49.0W    60 KT
 72HR VT     29/0000Z 27.0N  50.0W    65 KT
 96HR VT     30/0000Z 29.5N  50.5W    65 KT
120HR VT     01/0000Z 31.5N  50.5W    65 KT


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