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SUBTROPICAL STORM KYLE DISCUSSION NUMBER   5
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT SAT SEP 21 2002

THERE HAS BEEN LITTLE CHANGE IN THE STRUCTURE OF KYLE OVER THE
PAST 6 HR.  THE LOW-LEVEL CENTER IS PARTLY EXPOSED ON THE SOUTH AND
WEST SIDES OF THE PRIMARY CONVECTIVE BANDS...AND ANTICYCLONIC
OUTFLOW IS PRESENT...MOST NOTABLY OVER THE NORTHERN SEMICIRCLE.
EXPERIMENTAL CYCLONE PHASE DIAGRAMS FROM PENN STATE INDICATE THAT
KYLE MAY HAVE A WEAK WARM CORE IN AGREEMENT WITH EARLIER AMSU
DATA.  HOWEVER...A 1506Z TRMM OVERPASS INDICATES THAT THE WIND
FIELD IS STILL BROAD WITH A LARGE RADIUS OF MAXIMUM WINDS.  THUS...
KYLE WILL REMAIN A SUBTROPICAL STORM FOR THIS ADVISORY.  THE MAXIMUM
INTENSITY REMAINS 40 KT BASED ON SUBTROPICAL INTENSITY ESTIMATES
OF 35-40 KT AND 45-50 KT FROM AFWA AND TAFB...AND A TROPICAL
INTENSITY ESTIMATE OF 45 KT FROM SAB.
 
THE INITIAL MOTION IS NOW 020/7.  WATER VAPOR IMAGERY CONTINUES
TO INDICATE THE SUBTROPICAL RIDGE TO THE EAST OF KYLE AND A
MID-LATITUDE SHORTWAVE PASSING TO THE NORTH OF THE STORM.  THERE IS
ALSO A DEEP-LAYER CYCLONIC CIRCULATION CENTERED BETWEEN BERMUDA AND
HISPANIOLA.  LARGE-SCALE MODELS INDICATE THAT RIDGING DEVELOPING
BEHIND THE MID-LATITUDE TROUGH SHOULD BLOCK THE NORTHWARD MOTION...
WITH THE STORM EVENTUALLY ACQUIRING A WESTWARD OR WEST-SOUTHWESTWARD 
MOTION.  THE HEADACHES ARE COMING FROM HOW THE CYCLONE WILL GET
FROM THE CURRENT TO THE EVENTUAL MOTION.  NHC TRACK GUIDANCE
CONTINUES TO RESEMBLE A SQUASHED SPIDER...WITH MANY DIVERGING 
OPINIONS ON THE MOTION FOR THE NEXT 36-48 HR.  THE OFFICIAL FORECAST
CALLS FOR KYLE TO SWING A LITTLE MORE EASTWARD THAN EARLIER FORECAST
AND MAKE A CLOCKWISE LOOP BEFORE MOVING BACK TOWARD THE WEST- 
SOUTHWEST.  AS NOTED 6 HR AGO...WHILE CONFIDENCE IS HIGH THAT KYLE
WILL NOT GO VERY FAR IN THE NEXT 72 HR...THERE IS LOW CONFIDENCE IN 
THE EXACT TRACK.
 
THERE IS LITTLE CHANGE IN THE INTENSITY FORECAST PHILOSOPHY FROM THE 
PREVIOUS PACKAGE.  KYLE SHOULD REMAIN IN A FAVORABLE LIGHT SHEAR 
ENVIRONMENT OVER 26-27C SEA SURFACE TEMPERATURES...AND THUS STEADY 
DEVELOPMENT IS EXPECTED.  THE STORM COULD BECOME FULLY TROPICAL
TONIGHT OR SUNDAY.  THERE REMAINS ONE POSSIBLE NEGATIVE FACTOR...A
WEAK UPPER-LEVEL TROUGH THAT MAY PERSIST NEAR THE STORM.  THE 
INTENSITY FORECAST REMAINS BASED ON THE PREMISE THAT THIS WILL ONLY
SLOW THE CURRENT DEVELOPMENT AND NOT STOP IT.
 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     21/2100Z 32.0N  51.2W    40 KTS
12HR VT     22/0600Z 32.6N  50.9W    45 KTS
24HR VT     22/1800Z 32.8N  50.5W    50 KTS
36HR VT     23/0600Z 32.4N  50.6W    55 KTS
48HR VT     23/1800Z 32.0N  51.5W    60 KTS
72HR VT     24/1800Z 31.5N  53.0W    70 KTS
 
 
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