WDPN31 PGTW 271500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 33W (KOTO) WARNING NR 012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.8N 113.8E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 373 NM EAST-SOUTHEAST OF DA NANG, VIETNAM
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS AN EXPOSED LOW-
LEVEL CIRCULATION CENTER (LLCC), WITH DEEP CONVECTION SHEARED OVER THE 
WESTERN SEMICIRCLE. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY 
REVEALS A TIGHT THERMAL GRADIENT ALONG THE EASTERN EDGE OF THE CDO 
ASSOCIATED WITH THE HIGH (25-30 KNOTS) SOUTHEASTERLY VERTICAL WIND 
SHEAR (VWS). IN ADDITION TO THE HIGH VWS, DRY AIR ENTRAINMENT OVER
THE EASTERN QUADRANT IS AIDING IN WEAKENING THE SYSTEM. THE
DETERIORATING CONVECTIVE STRUCTURE IS CLEARLY EVIDENT IN A 271131Z 
SSMIS 91GHZ MICROWAVE IMAGE, WHICH SHOWS SHALLOW BANDING WRAPPING INTO 
A DEFINED LLCC, WITH DEEP CONVECTIVE BANDING OVER THE NORTHERN 
PERIPHERY AND WESTERN QUADRANT. BASED ON THE WEAKENED STRUCTURE, THE 
INITIAL INTENSITY HAS BEEN DECREASED TO 65 KNOTS, WHICH IS IN
CLOSER AGREEMENT WITH THE CIMSS OBJECTIVE INTENSITY ESTIMATES RANGING 
FROM 58 TO 65 KNOTS. WITH THE EXCEPTION OF THE PGTW FIX, THE FIXES ARE 
POSITIONED TOO FAR INTO THE DEEP CONVECTION RATHER THAN NEAR THE 
DECOUPLED LOW-LEVEL CIRCULATION CENTER.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: COMPETING STEERING PATTERN WITH SYSTEM
LOCATED BETWEEN A BROAD EASTERN SUBTROPICAL RIDGE (STR) TO THE EAST
AND A BROAD STR TO THE WEST OVER SOUTHEAST ASIA. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T5.0 - 90 KTS
   KNES: T4.5 - 77 KTS
   DEMS: T5.0 - 90 KTS
   CIMSS SATCON: 59 KTS AT 271131Z
   CIMSS ADT: 65 KTS AT 271130Z
   CIMSS AIDT: 58 KTS AT 271130Z
   CIMSS D-MINT: 58 KTS AT 271132Z
   CIMSS D-PRINT: 60 KTS AT 271230Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 30-35 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT OVER THE EASTERN QUADRANT

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: HIGH VWS IS EXPECTED TO PERSIST THROUGH TAU
36, WHICH WILL LEAD TO A SIGNIFICANT WEAKENING TREND THROUGH TAU
36. THE SYSTEM WILL TRACK SLOWLY NORTHWARD ALONG THE WESTERN PERIPHERY 
OF THE EASTERN STR, WITH A SHARP WESTWARD TURN THROUGH TAU 120 AS THE 
SYSTEM ENCOUNTERS THE WEAK EXTENSION OF THE WESTERN STR. A BRIEF 
PERIOD OF RELAXED VWS OCCURS BETWEEN TAU 36 AND TAU 96, HOWEVER, DRY 
AIR ENTRAINMENT AND UPWELLING COOLER WATER ARE EXPECTED TO HINDER 
DEVELOPMENT. AFTER TAU 96, VWS INCREASES TO HIGH LEVELS AIDING IN 
FURTHER WEAKENING.  

MODEL DISCUSSION: DUE TO THE COMPETING STEERING ENVIRONMENT, THE
270600Z GEFS AND EPS RUNS SHOW A WIDE CHAOTIC SPREAD, WITH A MORE 
DEFINITIVE WESTWARD TRACK OVER VIETNAM AFTER TAU 120. DETERMINISTIC 
GUIDANCE IS IN FAIR AGREEMENT THROUGH TAU 72, WITH A GENERALLY 
WESTWARD TRACK GROUPING OF SOLUTIONS AFTER TAU 72. THERE IS LOW 
CONFIDENCE IN THE JTWC INTENSITY FORECAST DUE TO THE SLOW TRACK AND 
POTENTIAL FOR UPWELLING COOLER WATER TO WEAKEN THE SYSTEM. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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