WDXS31 PGTW 261500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05S (DARIAN) WARNING 
NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.7S 84.8E
   INITIAL INTENSITY: 110 KTS
   GEOGRAPHIC REFERENCE: 923 NM SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 36 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TIGHTLY
WRAPPED DEEP CONVECTION SURROUNDING A 19 NM DIAMETER EYE. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A CLEAR
DEPICTION OF THE EYE IN RECENT MICROWAVE SATELLITE IMAGERY,
INCLUDING 260819Z AMSR2 AND 261022Z SSMIS PASSES. THE INITIAL
INTENSITY OF 110 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON
SUBJECTIVE DVORAK CURRENT INTENSITY ESTIMATES FROM PGTW, KNES,
FMEE, AND FIMP AS WELL AS AUTOMATED INTENSITY ESTIMATES FROM
UW-CIMSS INDICATING A NARROW RANGE OF POSSIBLE VALUES FROM
APPROXIMATELY 102 TO 116 KNOTS. TC 05S HAS WEAKENED SLIGHTLY OVER
THE PAST SIX HOURS AFTER COMPLETING A THIRD ROUND OF RAPID
INTENSIFICATION TO APPROXIMATELY 115 KNOTS AT 260600Z. PASSAGE OVER
A PATCH OF RELATIVELY WARMER WATER AND EXCEPTIONAL OUTFLOW BOTH
POLEWARD AND TOWARD AN UPPER-LEVEL LOW SITUATED TO THE WEST AIDED
THE RECENTLY OBSERVED INTENSIFICATION TREND.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGING TO THE SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   KNES: T6.0 - 115 KTS
   FMEE: T6.0 - 115 KTS
   FIMP: T5.5 - 102 KTS
   CIMSS SATCON: 116 KTS AT 260749Z
   CIMSS ADT: 115 KTS AT 261215Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG DUAL-CHANNEL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 05S WILL ACCELERATE SOUTHWESTWARD IN THE
NEAR TO MEDIUM TERM AS THE SUBTROPICAL STEERING RIDGE CONTINUES TO 
BUILD TO THE SOUTHEAST. AFTER TAU 72, THE SYSTEM WILL GRADUALLY TURN
POLEWARD AS IT REACHES AND ROUNDS THE WESTERN PERIPHERY OF THE
STEERING RIDGE AXIS. THE UPPER-LEVEL PATTERN IS EXPECTED TO REMAIN
GENERALLY FAVORABLE THROUGH TAU 72, WITH LOW TO MODERATE VERTICAL
WIND SHEAR AND SUPPORTIVE OUTFLOW. HOWEVER, THE SYSTEM WILL
WEAKEN AS IT TRACKS ACROSS PROGRESSIVELY COOLER WATER. TC 05S IS 
EXPECTED TO CROSS THE 26C ISOTHERM WITHIN 24 HOURS. THE WEAKENING 
TREND WILL MODERATE IN THE EXTENDED PERIOD AS THE SYSTEM ENCOUNTERS 
AN UPPER-LEVEL TROUGH NEAR THE STEERING RIDGE AXIS, WHICH WILL 
PROVIDE BAROCLINIC ENERGY AND SUPPORT TRANSITION TO A SUBTROPICAL 
CYCLONE.  

MODEL DISCUSSION: NUMERICAL MODELS ARE IN EXCELLENT AGREEMENT
REGARDING THE TRACK FORECAST, WHICH IS PLACED NEAR THE MULTI-MODEL
CONSENSUS WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS ALSO IN GOOD
OVERALL AGREEMENT. THERE IS SOME UNCERTAINTY IN THE RATE OF
WEAKENING PRIOR TO SUBTROPICAL TRANSITION, BUT A LEVELING AROUND 40
TO 50 KNOTS IN THE EXTENDED RANGE IS HIGHLY PROBABLE.

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