HOME	ARCHIVES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

ZCZC MIATCDAT2 ALL
TTAA00 KNHC DDHHMM
SUBTROPICAL STORM KYLE DISCUSSION NUMBER   4
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT SAT SEP 21 2002

KYLE CONTINUES TO BECOME BETTER ORGANIZED THIS MORNING...WITH
CONVECTIVE BANDING INCREASING JUST EAST OF THE CENTER AND THE FIRST
INDICATIONS OF A DEVELOPING CENTRAL DENSE OVERCAST.  THE SYSTEM
CONTINUES TO DEVELOP ANTICYCLONIC OUTFLOW AT UPPER LEVELS...AND
THE AMSU INSTRUMENTS ON THE NOAA POLAR ORBITING SATELLITES ARE
STARTING TO DETECT AN UPPER-LEVEL WARM CORE.  HOWEVER...THE CENTER 
IS NOT YET INVOLVED ENOUGH WITH THE CONVECTION TO CALL THE SYSTEM 
FULLY TROPICAL.  THE INITIAL INTENSITY OF 40 KT IS BASED ON
SUBTROPICAL INTENSITY ESTIMATES OF 45-50 KT FROM TAFB AND 35-40 KT
FROM AFWA...ALONG WITH A 35 KT TROPICAL INTENSITY ESTIMATE FROM SAB.
 
THE INITIAL MOTION IS 360/6. WATER VAPOR IMAGERY INDICATES 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 ACQUIRING A SOUTHWARD OR WESTWARD MOTION.  THE BIG
QUESTIONS ARE HOW MUCH OF EACH AND WHEN.  NHC TRACK GUIDANCE
RESEMBLES THE PROVERBIAL SQUASHED SPIDER...WITH MANY VARIATIONS
ON LOOPS AND HAIRPIN TURNS.  THERE ARE INDICATIONS THAT KYLE MAY
MAKE SOME KIND OF CLOCKWISE LOOP AS OPPOSED TO THE COUNTER-CLOCKWISE
LOOP MORE PROMINENT IN EARLIER MODEL RUNS.  BASED ON THIS...THE
OFFICIAL FORECAST IS NUDGED A LITTLE TO THE EAST AND SOUTH OF THE
PREVIOUS TRACK...CALLING FOR A SMALL LOOP BEFORE A SOUTHWESTWARD
MOTION BEGINS.  IT SHOULD BE NOTED THAT WHILE CONFIDENCE IS HIGH
THAT KYLE WILL NOT GO VERY FAR IN THE NEXT 72 HR...THERE IS LOW
CONFIDENCE IN THE EXACT TRACK.
 
KYLE REMAINS IN A FAVORABLE LIGHT SHEAR ENVIRONMENT OVER 26-27C
SEA SURFACE TEMPERATURES...AND THESE CONDITIONS ARE FORECAST TO
CONTINUE THROUGH THE FORECAST PERIOD.  THUS...STEADY DEVELOPMENT IS 
EXPECTED.  THE STORM WILL LIKELY BECOME FULLY TROPICAL LATER
TODAY OR TONIGHT IF PRESENT TRENDS CONTINUE.  ONE POSSIBLE NEGATIVE
FACTOR IS THAT MOST LARGE-SCALE MODELS INDICATE A WEAK UPPER-LEVEL 
TROUGH MAY PERSIST NEAR THE STORM.  THE INTENSITY FORECAST IS BASED
ON THE PREMISE THAT THIS WILL ONLY SLOW THE CURRENT DEVELOPMENT...
NOT STOP IT.
 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     21/1500Z 31.3N  51.6W    40 KTS
12HR VT     22/0000Z 32.1N  51.4W    45 KTS
24HR VT     22/1200Z 32.7N  51.0W    50 KTS
36HR VT     23/0000Z 32.5N  51.0W    55 KTS
48HR VT     23/1200Z 32.1N  51.9W    60 KTS
72HR VT     24/1200Z 31.5N  53.0W    70 KTS
 
 
NNNN