Tropical Storm LISA

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TROPICAL STORM LISA DISCUSSION NUMBER  14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL142010
500 AM AST FRI SEP 24 2010
 
INFRARED SATELLITE IMAGES SHOW THAT DEEP CONVECTION HAS RE-DEVELOPED
AROUND THE LOW-LEVEL CENTER OF LISA IN RECENT HOURS AS CONVECTION
IN A BAND WELL NORTHEAST OF THE CENTER HAS GENERALLY BEEN
DECREASING. DESPITE THE INCREASE IN CENTRAL CONVECTION...THE
OVERALL CLOUD PATTERN OF THE CYCLONE HAS NOT CHANGED MUCH IN
ORGANIZATION. DVORAK CI NUMBERS REMAIN UNCHANGED AT 2.0 AND 2.5
FROM SAB AND TAFB...RESPECTIVELY...AND ARE THE BASIS FOR KEEPING
THE INITIAL INTENSITY AT 35 KT. THE POSSIBILITY OF LISA INTENSIFYING
IS DECREASING. IN LESS THAN 24 HOURS...LISA IS EXPECTED TO REACH AN
ENVIRONMENT OF INCREASING SOUTHWESTERLY VERTICAL WIND SHEAR...
COOLER WATERS...AND HIGHER STABILITY. THESE FACTORS SHOULD PROMOTE
A STEADY WEAKENING...PERHAPS MORE RAPID THAN CURRENTLY FORECAST.
THE NHC INTENSITY FORECAST IS ABOUT THE SAME AS THE PREVIOUS ONE
BUT REMAINS A BIT LOWER THAN MOST OF THE STATISTICAL-DYNAMICAL
GUIDANCE.
 
AN 0349 UTC AMSR-E MICROWAVE OVERPASS WAS HELPFUL IN DETERMINING THE
CENTER OF LISA. THE CYCLONE APPEARS TO BE DRIFTING NORTHEASTWARD...
AND THE INITIAL MOTION ESTIMATE IS 035/04. GLOBAL MODELS SHOW LISA
MOVING GENERALLY NORTHWARD WITH SOME INCREASE IN FORWARD SPEED
DURING THE NEXT COUPLE OF DAYS...STEERED AROUND THE WESTERN
PERIPHERY OF A LOW- TO MID-LEVEL RIDGE OVER NORTHWEST AFRICA. AFTER
THAT...A WEAKER LISA OR ITS REMNANTS SHOULD MOVE NORTH-
NORTHWESTWARD IN THE LOW-LEVEL FLOW AND EVENTUALLY DISSIPATE. THE
NEW NHC TRACK FORECAST IS ADJUSTED A BIT TO THE RIGHT BUT NOT AS
FAR EAST AS THE GFDL/HWRF/UKMET WHICH GENERALLY HAVE STRONGER AND
LIKELY UNREALISTIC REPRESENTATIONS OF LISA...ESPECIALLY BEYOND 48
HOURS. THE NHC TRACK IS LEFT OF THE DYNAMICAL MODEL CONSENSUS AND
ROUGHLY IN THE MIDDLE OF THE GUIDANCE ENVELOPE.
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      24/0900Z 18.4N  27.7W    35 KT
 12HR VT     24/1800Z 19.2N  27.9W    40 KT
 24HR VT     25/0600Z 20.6N  28.3W    35 KT
 36HR VT     25/1800Z 22.1N  28.8W    30 KT
 48HR VT     26/0600Z 23.6N  29.2W    30 KT
 72HR VT     27/0600Z 26.0N  30.5W    25 KT...POST-TROP/REMNT LOW
 96HR VT     28/0600Z 27.5N  32.0W    20 KT...POST-TROP/REMNT LOW
120HR VT     29/0600Z...DISSIPATED
 
$$
FORECASTER KIMBERLAIN
 
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