WDXS31 PGTW 281500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (VERNON) WARNING NR 
008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.0S 86.9E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 944 NM EAST-SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A TIGHTLY 
COMPACT SYMMETRICAL SYSTEM. THE LOW-LEVEL CIRCULATION (LLC) IS NOW 
TUCKED BACK UNDER THE MAIN AREA OF FLARING CONVECTION AND IS GAINING 
INTENSITY. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED 
ON THE EIR LOOP, AND A PARTIAL 281100Z SSMIS 91GHZ IMAGE. THE INITIAL 
INTENSITY OF 50KTS IS ASSESSED WITH MEDIUM CONFIDENCE AND IS SLIGHTLY 
HIGHER THAN MULTIPLE AGENCIES CURRENT INTENSITY DVORAK ESTIMATES AND 
ADT. THE SLOW MOVEMENT AND SYMMETRICAL NATURE IS ALSO INDICATIVE OF A 
DEEPENING SYSTEM. ENVIRONMENTAL ANALYSIS INDICATES A FAVORABLE 
ENVIRONMENT WITH LOW VERTICAL WIND SHEAR, WARM SEA SURFACE 
TEMPERATURES, AND MODERATE RADIAL OUTFLOW.

INITIAL WIND RADII BASIS: PERSISTENCE.

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
SOUTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   FMEE: T3.5 - 55 KTS
   FIMP: T3.0 - 45 KTS
   CIMSS SATCON: 52 KTS AT 280742Z
   CIMSS ADT: 49 KTS AT 281215Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 14S WILL CONTINUE ON A SOUTHWESTWARD TRACK 
UNDER THE INFLUENCE OF THE STR FOR THE NEXT 72-96 HOURS. AFTERWARD, TC 
14S WILL ROUND THE STR AXIS AND THEN TRACK MORE SOUTHWARD. THE 
INITIAL FAVORABLE ENVIRONMENT WILL FUEL A MODEST INTENSIFICATION TO A 
PEAK OF 60KTS BY TAU 48, AFTERWARD, THE INFLUX OF COOL DRY AIR IN THE 
LOWER LEVELS WILL HAMPER ANY FURTHER INTENSIFICATION. BY TAU 96, 
COOLING SEA SURFACE TEMPERATURES WILL CONTRIBUTE TO FURTHER WEAKENING 
AND SIMULTANEOUSLY BEGIN SUBTROPICAL TRANSITION AS IT APPROACHES THE 
COLD BAROCLINIC ZONE, COMPLETING TRANSITION BY TAU 120 AND WEAKENING 
TO 50KTS.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH ONLY
MINIMAL SPREADING AT TAU 48 WITH A MAX OF 120NM, THEN GRADUALLY
SPREADS TO 323NM BY TAU 120 WITH AFUM THE FAR LEFT OF TRACK
OUTLIER, LENDING MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST THAT
IS LAID JUST TO THE RIGHT OF CONSENSUS TO OFFSET AFUM. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
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