Advisories

WDPN31 PGTW 040300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (DOLPHIN) WARNING NR 033//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.1N 143.2E
   INITIAL INTENSITY: 100 KTS
   GEOGRAPHIC REFERENCE: 836 NM EAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 48 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TYPHOON 12W (DOLPHIN) APPEARS TO HAVE RESUMED ITS EYEWALL REPLACEMENT 
CYCLE (ERC) AFTER A TEMPORARY PAUSE. ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY (MSI) DEPICTS A CONTRACTING AND CLOUD FILLED EYE AS WELL AS 
INCREASINGLY SYMMETRICAL CONVECTIVE STRUCTURE. A 032035Z 37 GHZ SSMIS 
MICROWAVE IMAGE DEPICTS TWO CONCENTRIC EYEWALLS AND A WELL-DEFINED 
MOAT BETWEEN THE TWO. ADDITIONALLY, EIR IMAGERY HAS SHOWN THAT THE EYE 
TEMPERATURE HAS COOLED 14 DEGREES TO 2 C. ENVIRONMENTAL ANALYSIS 
REVEALS FAVORABLE CONDITIONS WITH WARM (29-30) SEA SURFACE 
TEMPERATURES (SSTS), LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS), AND 
STRONG RADIAL OUTFLOW ALOFT WITH WELL DEFINED CIRRUS STRIATIONS 
VISIBLE IN MSI IMAGERY. THE INITIAL POSITION IS ASSESSED WITH HIGH 
CONFIDENCE BASED ON THE VISIBLE EYE. INITIAL INTENSITY IS ASSESSED 
WITH HIGH CONFIDENCE BASED ON A 032025Z RCM-3 SAR IMAGE WITH A MAXIMUM 
WINDSPEED OF 96 KTS, AND AGREEMENT BETWEEN THE CIMSS OBJECTIVE 
ESTIMATES AND AGENCY DVORAK FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: COMBINATION OF SUBTROPICAL RIDGES
(STRS) CENTERED TO THE NORTHEAST AND NORTHWEST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T5.5 - 102 KTS
   RCTP: T5.0 - 90 KTS
   KNES: T5.0 - 90 KTS
   CIMSS SATCON: 100 KTS AT 032300Z
   CIMSS ADT: 107 KTS AT 032330Z
   CIMSS AIDT: 98 KTS AT 032330Z
   CIMSS D-PRINT: 85 KTS AT 032330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TY DOLPHIN IS FORECAST TO CONTINUE TRACKING
WESTWARD UNDER THE INFLUENCE OF A SUBTROPICAL RIDGE (STR) CENTERED
TO THE NORTHEAST, TRANSITIONING TO THE INFLUENCE OF THE STR CENTERED 
TO THE NORTHWEST BUT WITH NO LARGE SHIFT IN TRACK EXPECTED AS THIS 
CHANGE OCCURS. TY 12W HAS SLOWED SLIGHTLY IN TRANSLATIONAL SPEED IN 
THE SHORT TERM, LIKELY DUE TO THIS TEMPORARY SHIFT IN STEERING 
INFLUENCES. TY DOLPHIN IS FORECAST TO INCREASE IN SPEED UNTIL TAU 72 
WHERE IT WILL SLOW AGAIN AND BEGIN A WEST-NORTHWESTWARD TURN AS THE 
STR TO THE NORTH RETREATS EASTWARD. THE CONTINUED WESTWARD TRACK HAS 
RESULTED IN A CLOSER CPA TO KADENA, BUT OCCURRING A FEW HOURS LATER 
THAN THE PREVIOUS FORECAST. IN REGARDS TO THE INTENSITY FORECAST, 
THERE IS SOME UNCERTAINTY DUE TO THE ONGOING ERC AND POTENTIAL FOR A 
SHORT-TERM WEAKENING TREND. HOWEVER, A PLATEAU IN INTENSITY IS MORE 
LIKELY IF THE ERC CONTINUES TO DRAG ON AND NOT QUITE COMPLETE. 
CURRENTLY, TY 12W IS FORECAST IN ACCORDANCE WITH THE LATTER SCENARIO 
AND EXPECTED TO INCREASE IN THE SHORT TERM TO 110 KTS.

MODEL DISCUSSION: MODEL TRACK GUIDANCE IS IN GOOD AGREEMENT OUT TO
TAU 72 WITH 80 NM CROSS TRACK SPREAD. TAU 72 TO 120, MODELS SPLIT ON
HOW SHARP OF A NORTHWARD TURN TY 12W WILL MAKE. THE OFFICIAL JTWC
FORECAST IS LAID WITH HIGH CONFIDENCE OUT TO TAU 72 IN BETWEEN THE
JTWC MULTI-MODEL CONSENSUS AND AI CONSENSUS. THE FORECAST TRACK FOR
TAU 72 TO 120 IS PLACED WITH MEDIUM CONFIDENCE, MORE IN LINE WITH
THE GOOGLE DEEP MIND, AS THE JTWC CONSENSUS IS INFLUENCED BY THE
SLOWER TRACK SPEEDS OF GFS, GFS ENSEMBLE MEAN, AND NAVGEM AND THUS
TURNS NORTHWARD MUCH EARLIER. MODEL INTENSITY GUIDANCE HAS INCREASED 
IN SPREAD WITH SEVERAL RI AIDS POPULATING FOR A SPREAD OF 45 KTS AT 
TAU 24. THE OFFICIAL JTWC FORECAST INTENSITY IS THUS ASSESSED WITH LOW 
CONFIDENCE THROUGHOUT THE REMAINDER OF THE FORECAST PERIOD, CLOSELY IN 
LINE WITH THE JTWC MULTI-MODEL CONSENSUS.

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