WDPN31 PGTW 040300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 09W (BAVI) WARNING NR 
013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.5N 151.5E
   INITIAL INTENSITY: 140 KTS
   GEOGRAPHIC REFERENCE: 395 NM EAST OF HAGATNA, GUAM
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 44 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) REVEALS A HIGHLY
ORGANIZED AND NEARLY SYMMETRIC DEEP-CONVECTIVE CANOPY ENCOMPASSING
A SHARPLY DEFINED 20 NM DIAMETER EYE ASSOCIATED WITH SUPER TYPHOON
(STY) 09W (BAVI). SYNOPTIC AND MESOSCALE ENVIRONMENTAL DIAGNOSTICS
REVEAL A HIGHLY CONDUCIVE THERMODYNAMIC AND KINEMATIC PROFILE
SUPPORTED BY VIGOROUS UPPER-LEVEL RADIAL OUTFLOW, ABUNDANT
DEEP-TROPOSPHERIC MOISTURE CONTENT, MINIMAL VERTICAL WIND SHEAR
(VWS) CONSTRAINED BETWEEN 5-10 KTS, AND ELEVATED SEA SURFACE
TEMPERATURES (SST) MEASURING 29-30 C. INITIAL POSITION IS ASSESSED
WITH HIGH CONFIDENCE ANCHORED PURELY ON THE EYE FEATURE IDENTIFIED
IN THE MSI. UTILIZING A CONSENSUS OF AGENCY SUBJECTIVE DVORAK DATA
AND OBJECTIVE SATELLITE DERIVED ALGORITHMS WHICH HOVER NEAR 140
KTS, THE INITIAL INTENSITY ESTIMATE IS SUBSTANTIATED AT 140 KTS
WITH EQUALLY HIGH CONFIDENCE.

INITIAL WIND RADII BASIS: A 032325Z METOP-B ASCAT PASS

CURRENT STEERING MECHANISM: ELONGATED EASTERN EXTENSION OF A
DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED EAST OF TAIWAN

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.0 - 140 KTS 
   RJTD: T6.5 - 127 KTS
   RCTP: T7.0 - 140 KTS 
   KNES: T7.0 - 140 KTS 
   CIMSS SATCON: 140 KTS AT 040000Z
   CIMSS ADT: 146 KTS AT 040000Z
   CIMSS AIDT: 143 KTS AT 040000Z
   CIMSS D-MINT: 136 KTS AT 032103Z
   CIMSS D-PRINT: 141 KTS AT 040030Z

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: HIGH
   INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

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

FORECAST DISCUSSION: FORECAST PHILOSOPHY REMAINS CONSISTENT WITH NO
SIGNIFICANT DEVIATIONS FROM THE PRIOR ISSUANCE. SYNOPTIC SCALE
STEERING DYNAMICS ARE CURRENTLY GOVERNED BY AN EASTERN EXTENSION OF
A STR ANCHORED TO THE NORTHEAST. TRANSLATIONAL VELOCITY CONTINUES
TO DECELERATE AND IS NOT EXPECTED TO INCREASE UNTIL TAU 24, AS STY
09W MAINTAINS A WESTWARD HEADING. THIS TRANSIENT DECELERATION IS
INDUCED BY A PASSING MIDLATITUDE LONGWAVE TROUGH PROPAGATING TO THE
NORTH, WHICH FORCES A BIFURCATION IN THE BROAD RIDGING AND ORIENTS
THE RIDGE AXIS IMMEDIATELY POLEWARD OF THE SYSTEM. SUBSEQUENT TO
TAU 24, THE CYCLONIC VORTEX WILL ASSUME A WEST-NORTHWESTWARD
TRAJECTORY FOR THE REMAINDER OF THE PROGNOSIS WINDOW AS IT
ACCELERATES OUT OF THE WEAKENED STEERING REGIME. THE SYSTEM WILL
PRESS AGAINST THE NOW WEAKENING STR TO THE NORTHWEST, WHILE A
BUILDING RIDGE CENTERED TO THE NORTHEAST ASSUMES PRIMARY STEERING.
ALTHOUGH THE RATE OF INTENSIFICATION IS PROJECTED TO PLATEAU AMIDST
THIS STEERING SHIFT, PEAK WIND SPEEDS ARE ANTICIPATED TO REACH 145
KTS BETWEEN TAU 24 AND TAU 48. WITHIN THIS TIMEFRAME, THE SYSTEM
WILL COMMENCE INTERACTION WITH THE MARIANA ISLANDS ARCHIPELAGO,
DRIVING THE LOW-LEVEL CIRCULATION CENTER BETWEEN THE ISLANDS OF
ROTA AND TINIAN. ADDITIONAL MODULATION IN PEAK INTENSITY TIMING MAY
OCCUR DUE TO AN EYEWALL REPLACEMENT CYCLE (ERC) PROBABILISTICALLY
HIGHLIGHTED BY HIGH-RESOLUTION HAFS-A RUNS. AS THE CYCLONE
PROPAGATES FURTHER WEST-NORTHWESTWARD, PERIPHERAL ENTRAINMENT OF A
NORTHWESTERN DRY AIR MASS COMBINED WITH AN ESCALATION OF VWS,
REACHING 25 KTS BY TAU 96, WILL CATALYZE A SLOW, GRADUAL
DEGRADATION OF THE CONVECTIVE STRUCTURE AND INDUCE A WEAKENING
PHASE TOWARDS THE END OF THE CURRENT FORECAST PERIOD.

MODEL DISCUSSION: DYNAMICAL INTENSITY GUIDANCE REFLECTS MEDIUM
CONFIDENCE THROUGHOUT THE PROJECTION TIMEFRAME DUE TO GROWING
SPREAD IN MODEL SOLUTIONS LATER IN THE FORECAST. A CONSENSUS OF
NUMERICAL GUIDANCE INDICATES THE CYCLONE HAS LIKELY ATTAINED OR IS
IN CLOSE PROXIMITY TO ITS PEAK INTENSITY. HOWEVER, THE VORTEX
REMAINS CAPABLE OF SUSTAINING SUPER TYPHOON STRENGTH THROUGHOUT THE
MAJORITY OF THE CURRENT FORECAST PERIOD. CONSEQUENTLY, THE
POTENTIAL COMMENCEMENT OF AN EYEWALL REPLACEMENT CYCLE (ERC)
INTRODUCES UNCERTAINTY REGARDING NEAR-TERM INTENSITY FLUCTUATIONS.
HIGH-RESOLUTION MESOSCALE MODELS SUCH AS HAFS PROJECT AN AGGRESSIVE
KINEMATIC PEAK OF 145 KTS, WHEREAS DETERMINISTIC GFS RUNS PROPOSE A
RESTRAINED RANGE OF 110 TO 115 KTS. DRIVEN BY THE HIGHLY CONDUCIVE
THERMODYNAMIC PREDICTIONS, THE OFFICIAL JTWC INTENSITY PROFILE IS
BIASED TOWARD THE UPPER BOUNDARY OF THE DYNAMICAL CONSENSUS.
CONVERSELY, DETERMINISTIC TRACK GUIDANCE MAINTAINS EXCEPTIONAL
COHESION, EVIDENCED BY A TIGHT CROSS-TRACK SPREAD OF A 60 NM DURING
THE CLOSEST POINT OF APPROACH (CPA) TO TINIAN AND ROTA.
CONSEQUENTLY, THE JTWC TRACK FORECAST IS ESTABLISHED WITH HIGH
CONFIDENCE IN CLOSE ALIGNMENT WITH THE MULTI-MODEL CONSENSUS MEAN,
WEIGHING SLIGHTLY SOUTHWARD TO INCORPORATE THE VERY MINOR SOUTHWARD
SHIFT, PRIMARILY DRIVEN BY CURRENT WESTWARD TRANSIT.

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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