WDXS31 PGTW 160900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 13S (DJOUNGOU) WARNING 
NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.1S 65.7E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 536 NM EAST-NORTHEAST OF PORT LOUIS,
MAURITIUS
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A LARGE SYSTEM
THAT HAS ONCE AGAIN SLOWED DOWN AS IT DEVELOPED A BANDING EYE. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE
DEFINED BANDING EYE FEATURE IN THE MSI LOOP. THE INITIAL INTENSITY
IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON THE CONCENTRIC DVORAK
ESTIMATES FROM PGTW, KNES, AND FIMP. ANALYSIS INDICATES A HIGHLY
FAVORABLE ENVIRONMENT WITH WARM SST, LOW VWS, AND STRONG
DUAL-CHANNEL OUTFLOW.

INITIAL WIND RADII BASIS: PERSISTENCE.

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE EXTENSION TO THE
NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   FIMP: T3.5 - 55 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 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 13S WILL CONTINUE EAST-SOUTHEASTWARD THEN
SOUTHEASTWARD UNDER THE NER EXTENSION TO THE NORTHEAST. THE HIGHLY
FAVORABLE ENVIRONMENT, ENHANCED BY A POOL OF HIGH OCEAN HEAT
CONTENT DOWNSTREAM WILL FUEL A RAPID INTENSIFICATION TO A PEAK OF
105KTS BY TAU 24. AFTERWARD, COOLING SST AND DIMINISHING
EQUATORWARD OUTFLOW WILL GRADUALLY WEAKEN THE SYSTEM TO 90KTS BY
TAU 72. AFTERWARD, THE SYSTEM WILL ENTER THE BAROCLINIC ZONE AND
BEGIN EXTRA-TROPICAL TRANSITION (ETT). CONCURRENTLY, AS THE CYCLONE
DRIFTS DEEPER INTO THE PREVAILING WESTERLIES, INCREASING VWS
(30KTS+) WILL CONTRIBUTE TO RAPID EROSION AND DECAY WITH TC DJOUNGOU
UNCHAINED AND DECAPITATED FROM ITS DEEP CENTRAL CONVECTION. BY TAU
120, THE SYSTEM WILL COMPLETE ETT AND TRANSFORM INTO A GALE-FORCE
COLD CORE LOW WITH AN EXPANDING WIND FIELD. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH A
GRADUAL AND EVEN SPREAD TO A MERE 170NM BY TAU 72; HOWEVER, GIVEN
THE UNCERTAINTY OF ITS CURRENT SLOW FORWARD MOTION, THERE IS ONLY
MEDIUM CONFIDENCE IN THE NEAR- TO MID-TERM PORTION OF THE JTWC
TRACK FORECAST. AFTER TAU 72, THE MODEL ENVELOPE REMAINS TIGHT AND
SPREAD OUT EVENLY TO 335NM; HOWEVER, ALONG-TRACK SPEEDS
SIGNIFICANTLY DIFFER AMONG THE MEMBERS WITH NVGM AND AFUM
SIGNIFICANTLY FASTER THAN THE MAIN PACK. IN VIEW OF THIS, THERE IS
LOW CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC TRACK FORECAST
THAT IS HELD BACK SLIGHTLY SHORTER THAN THE CONSENSUS TO OFFSET THE
FORWARD OUTLIERS. 

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