WDPN21 PGTW 291500 							
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 12W (DOLPHIN)
WARNING NR 011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.2N 167.7E
   INITIAL INTENSITY: 130 KTS
   GEOGRAPHIC REFERENCE: 254 NM SOUTH-SOUTHEAST OF WAKE ISLAND
   MOVEMENT PAST 6 HOURS: 310 DEGREES AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 40 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS SUPER
TYPHOON (STY) 12W SIGNIFICANTLY INTENSIFYING ONCE AGAIN, AFTER HAVING 
QUICKLY REBOUNDED FROM THE SLIGHT WEAKENING INDUCED BY THE EARLIER
EYEWALL REPLACEMENT CYCLE (ERC). 12W HAS A VERY WELL-DEFINED AND 
SLIGHTLY WOBBLY EYE MEASURING 15NM IN DIAMETER. THE ENVIRONMENT 
REMAINS EXCEPTIONALLY FAVORABLE, CHARACTERIZED BY LOW (5-10 KTS) 
VERTICAL WIND SHEAR (VWS), HIGH (29-30 C) SEA SURFACE TEMPERATURES 
(SST), ROBUST DUAL-CHANNEL OUTFLOW, AND EXCESSIVE OCEAN HEAT CONTENT 
(OHC). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON 
THE CLEAR EYE IN ANIMATED EIR. THE INITIAL INTENSITY OF 130 KTS IS 
ASSESSED WITH MEDIUM CONFIDENCE IS BASED ON THE AGENCY DVORAK FIXES 
AND CIMSS INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE.

CURRENT STEERING MECHANISM: THE SOUTHWESTERN PERIPHERY OF A
DEEP-LAYER SUBTROPICAL RIDGE (STR) COMPLEX OVER THE CENTRAL NORTH
PACIFIC

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.5 - 127 KTS
   RJTD: T5.5 - 102 KTS
   KNES: T6.5 - 127 KTS
   CIMSS ADT: 129 KTS AT 291230Z
   CIMSS AIDT: 121 KTS AT 291230Z 
   CIMSS D-PRINT: 123 KTS AT 291230Z
   						

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 5-10 KTS
   SST: 20-30 CELSIUS
   OUTFLOW: STRONG DUAL-CHANNEL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH						 
   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: STY 12W (DOLPHIN) IS FORECAST TO CONTINUE 
TRACKING NORTHWESTWARD THROUGH TAU 72, STEERED ALONG THE SOUTHWESTERN
PERIPHERY OF A COMPLEX RIDGE OVER THE CENTRAL NORTH PACIFIC. AROUND 
TAU 72, THE LONGWAVE TROUGH CURRENTLY DIGGING INTO THE STEERING STR 
COMPLEX IS EXPECTED TO WEAKEN, ALLOWING FOR THE STR TO REBUILD TO 
THE NORTHEAST OF THE SYSTEM AND DEVELOP A WESTWARD EXTENSION. THIS 
CHANGE IN THE STEERING PATTERN WILL INDUCE A SLIGHT WESTWARD TURN 
AFTER TAU 72. REGARDING INTENSITY, 12W IS FORECAST TO CONTINUE TO 
INTENSIFY IN THE HIGHLY FAVORABLE ENVIRONMENT, THOUGH ITS PERIOD OF 
VIGOROUS INTENSIFICATION IS LIKELY OVER. DOLPHIN IS EXPECTED TO 
REACH ITS PEAK INTENSITY AT TAU 48 AT AN ANTICIPATED 155 KTS. GIVEN
THE HIGHLY FAVORABLE ENVIRONMENT, A PEAK HIGHER THAT 155 KTS IS 
VERY POSSIBLE. AFTER TAU 48, 12W WILL WEAKEN AS ITS INTENSITY
BECOMES UNSUSTAINABLE SIMULTANEOUS TO TRACKING INTO SLIGHTLY LOWER 
OHC VALUES WHICH WILL EXACERBATE ITS SELF-INDUCED UPWELLING. 
ADDITIONAL EYEWALL REPLACEMENT CYCLES (ERC) ARE POSSIBLE AND WOULD 
INTRODUCE UNPREDICTABLE INTENSITY FLUCTUATIONS THAT MAY NOT BE 
PRESENTLY REFLECTED IN THE OFFICIAL FORECAST. 

MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE REMAINS IN 
STRONG AGREEMENT THROUGHOUT THE FORECAST PERIOD, WITH LESS THAN 
120NM CROSS-TRACK SPREAD AT TAU 120. ALONG-TRACK SPREAD REMAINS 
MINIMAL FOR THE DURATION OF THE FORECAST PERIOD. AS A RESULT, THE 
JTWC TRACK FORECAST IS PLACED WITH OVERALL HIGH CONFIDENCE. 
RELIABLE INTENSITY AIDS ARE IN MODERATE AGREEMENT. THE HAFS-A 
SOLUTION DEPICTS A PEAK INTENSITY OF 170 KTS AT TAU 48, WHILE 
COAMPS-TC (BOTH GFS AND NAVGEM BOUNDARY CONDITION SOLUTIONS) DEPICT
A PEAK BETWEEN 145-150 KTS. THE JTWC INTENSITY FORECAST LIES SLIGHTLY
HIGHER THAN COAMPS AND SLIGHTLY LOWER THAN HAFS-A AND ASSESSED WITH 
MEDIUM CONFIDENCE FROM TAU 0-72 AND LOW CONFIDENCE THEREAFTER.

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