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TROPICAL STORM LOWELL DISCUSSION NUMBER   6
NATIONAL WEATHER SERVICE MIAMI FL
8 PM PDT WED OCT 23 2002

LAST-LIGHT VISIBLE IMAGERY INDICATES THAT THE CENTER OF LOWELL
IS SEPARATING FURTHER FROM THE DEEP CONVECTION DUE TO SOUTHERLY
OR SOUTHWESTERLY SHEAR.  WHAT CONVECTION IS PRESENT IS NOW IN A
BROADLY CURVED BAND WELL TO THE SOUTHEAST OF THE CENTER.  SATELLITE
INTENSITY ESTIMATES ARE 45 KT FROM SAB AND AFWA...AND 35 KT FROM
TAFB.  THE INITIAL INTENSITY REMAINS 40 KT FOR THIS ADVISORY.
 
THE EXPOSED CENTER IS NOW MOVING 270/7.  LOWELL IS ON THE SOUTH
SIDE OF A LOW/MID-LEVEL RIDGE...AND LARGE-SCALE GUIDANCE INDICATES
THIS STEERING FEATURE SHOULD PERSIST WITH PERHAPS SOME SLOW
WEAKENING THROUGH THE FORECAST PERIOD.  THIS SHOULD CAUSE THE
SHEARED LOWELL TO MOVE WESTWARD TO WEST-NORTHWESTWARD.  ALL TRACK
GUIDANCE SAVE LBAR AGREES WITH THIS SCENARIO...ALTHOUGH THERE IS
A FAIRLY LARGE SPREAD IN THE FORECAST SPEED.  THE OFFICIAL FORECAST
IS DOWN THE CENTER OF THE GUIDANCE AT 6-8 KT...WHICH COMPROMISES 
BETWEEN FASTER MODELS LIKE THE GFDL AND BAMS...AND SLOWER MODELS
SUCH AS THE UKMET.  THIS TRACK IS CONSIDERABLY THAN THE PREVIOUS
FORECAST...AND SOMEWHAT TO THE SOUTH.

LOWELL IS CURRENTLY IN A MARGINAL-AT-BEST SHEAR ENVIRONMENT...AND
THUS IS NOT LIKELY TO STRENGTHEN MUCH FURTHER.  LARGE-SCALE MODELS
SUGGEST THAT THE SHEAR COULD TEMPORARILY DECREASE IN 24-36 HR AS
AN UPPER-LEVEL RIDGE BUILDS NEAR OR SOUTH OF THE STORM.  BEYOND
THAT TIME...SIGNIFICANT NORTHWESTERLY SHEAR SHOULD DEVELOP AS THE
RIDGE AXIS SHIFTS SOUTHWARD.  THE INTENSITY FORECAST WILL CALL FOR
LITTLE CHANGE IN STRENGTH FOR 36 HR...FOLLOWED BY SLOW WEAKENING AS
THE ENVIRONMENT BECOMES MORE HOSTILE.
 
FORECASTER BEVEN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     24/0300Z 12.4N 132.8W    40 KTS
12HR VT     24/1200Z 12.5N 133.6W    40 KTS
24HR VT     25/0000Z 12.7N 134.9W    40 KTS
36HR VT     25/1200Z 13.0N 136.4W    40 KTS
48HR VT     26/0000Z 13.3N 138.0W    35 KTS
72HR VT     27/0000Z 14.0N 141.0W    30 KTS
 
 
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