WDPN31 PGTW 292100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 12W (DOLPHIN) WARNING NR
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.8N 166.8E
   INITIAL INTENSITY: 145 KTS
   GEOGRAPHIC REFERENCE: 210 NM SOUTH OF WAKE ISLAND
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 42 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS SUPER
TYPHOON 12W (DOLPHIN) WITH A WARM (18 C) EYE AND SYMMETRICAL CMG
RING SURROUNDING THE EYEWALL. THE SYSTEM HAS CLEARLY RECOVERED
FLAWLESSLY FROM THE EYEWALL REPLACEMENT CYCLE (ERC). A 291501Z
AMSR2 89 GHZ MICROWAVE IMAGE REVEALED A STRONG INNER EYEWALL WITH
INDICATIONS OF AN OUTER EYEWALL BEGINNING TO FORM ONCE AGAIN. THE
MPERC TOOL PROVIDED BY CIMSS CURRENTLY ANALYZES THERE TO BE A 78
PERCENT PROBABILITY OF ERC ONSET. THE INITIAL POSITION IS PLACED
WITH HIGH CONFIDENCE BASED ON THE DEFINED EYE IN ANIMATED EIR
IMAGERY. THE INITIAL INTENSITY OF 145 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE COMBINATION OF THE AGENCY DVORAK FIXES AND
CIMSS INTENSITY ESTIMATES LISTED BELOW. THE ENVIRONMENT CONTINUES
TO BE CHARACTERIZED AS HIGHLY FAVORABLE DUE TO STRONG RADIAL
OUTFLOW ALOFT, LOW (5-10 KTS) VERTICAL WIND SHEAR, AND WARM (29-30
C) SEA SURFACE TEMPERATURES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK

CURRENT STEERING MECHANISM: THE WESTERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR) CENTERED TO THE WEST OF HAWAII

AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T7.5 - 155 KTS
   RJTD: T6.5 - 127 KTS
   RCTP: T7.5 - 155 KTS
   KNES: T7.5 - 155 KTS
   PHFO: T7.5 - 155 KTS
   CIMSS ADT: 152 KTS AT 291800Z
   CIMSS AIDT: 140 KTS AT 291800Z
   CIMSS D-PRINT: 133 KTS AT 291800Z

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

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 IS FORECAST TO CONTINUE TRACKING
NORTHWESTWARD ALONG THE WESTERN PERIPHERY OF THE STR TO THE EAST
THROUGH TAU 72. AFTER TAU 72, 12W IS FORECAST TO TURN MORE WESTWARD
AS A LARGE RIDGE BUILDS AND ANCHORS TO THE NORTHWEST OF HAWAII.
NEAR TAU 120 A SEPARATE STR IS EXPECTED TO BUILD OVER THE SEA OF
JAPAN, EVENTUALLY BECOMING THE PRIMARY STEERING MECHANISM AT THE
END OF THE FORECAST PERIOD. IN TERMS OF INTENSITY, 12W IS FORECAST
TO MAINTAIN INTENSITY THROUGH TAU 24 WITH THE POSSIBILITY OF A
SECOND ERC BEGINNING, AS INDICATED BY THE AFOREMENTIONED AMSR2
MICROWAVE IMAGE. AFTER TAU 24, FURTHER GRADUAL INTENSIFICATION IS
FORECAST TO OCCUR THROUGH TAU 60 UNDER THE EFFECTS OF THE HIGHLY
FAVORABLE ENVIRONMENT. NEAR TAU 72, THE POLEWARD OUTFLOW CHANNEL
BECOMES RESTRICTED AND OCEAN HEAT VALUES BEGIN TO DROP. THESE TWO
FACTORS, ALONG WITH THE EXPANDING WIND FIELD, WILL CAUSE 12W TO
SLOWLY WEAKEN THROUGH THE END OF THE FORECAST PERIOD AS IT TRACKS
OFF TO THE WEST.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE CONTINUES TO BE IN
VERY GOOD AGREEMENT WITH A CROSS-TRACK SPREAD OF 100 NM AT TAU 72
AND 190 NM AT TAU 120. GALWEM AND UKMET MAKE UP THE FURTHEST
EQUATORWARD TRACKERS WHILE THE EC-AIFS MAKES UP THE NORTHERNMOST
TRACKER. THE JTWC TRACK FORECAST IS PLACED CLOSE TO THE MULTI-MODEL
CONSENSUS THROUGHOUT THE FORECAST PERIOD WITH OVERALL HIGH
CONFIDENCE. HAFS-A CONTINUES TO BE THE MOST AGGRESSIVE MODEL,
SUGGESTING A PEAK INTENSITY OF AROUND 180 KTS AT TAU 48. THE
REMAINDER OF GUIDANCE SHOWS A GENERALLY STABLE INTENSITY THROUGH
TAU 60. AFTER TAU 60, MODELS AGREE ON GRADUAL WEAKENING THROUGH THE
END OF THE FORECAST PERIOD. THE JTWC INTENSITY FORECAST IS PLACED
CLOSE TO THE CONSENSUS THROUGH TAU 36, THEN SLIGHTLY HIGHER
THROUGH TAU 120 DUE TO THE HAFS-A DEPICTION. THE UNCERTAINTY OF THE
TIMING OF ADDITIONAL ERC EVENTS CAUSES THERE TO BE MEDIUM
CONFIDENCE IN THE JTWC INTENSITY FORECAST.

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