WDPN31 PGTW 281500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (JANGMI) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.8N 135.5E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 876 NM SOUTH-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
A DIAGNOSIS OF THE SYNOPTIC ENVIRONMENT REVEALS FAVORABLE
CONDITIONS FOR CONTINUOUS DEVELOPMENT OF TROPICAL STORM (TS) 06W
(JANGMI), CHARACTERIZED BY MODERATE EQUATORWARD AND POLEWARD
OUTFLOW, A DEEPLY MOIST TROPOSPHERIC COLUMN, LOW (10-15 KTS)
VERTICAL WIND SHEAR, AND ELEVATED OCEANIC HEAT CONTENT COINCIDENT
WITH SEA SURFACE TEMPERATURES OF 29-30 C. ANIMATED ENHANCED
INFRARED (EIR) SATELLITE IMAGERY DEPICTS TS JANGMI AS IT CONTINUES TO
CONSOLIDATE. THE SYSTEM HAS RECENTLY PICKED UP SPEED AS THE
LOW-TO-MID LEVEL SUBTROPICAL RIDGE (STR) TO THE NORTHEAST CONTINUES
TO BUILD. THE VORTEX CORE REMAINS SOMEWHAT BROAD AS EVIDENCED BY
RECENT SCATTEROMETRY DATA - A 281136Z METOP-B AND A 281206Z METOP-C
ASCAT PASS. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE
AND IS DERIVED FROM THE PARTIALLY EXPOSED LOW-LEVEL CIRCULATION
CENTER (LLCC) IN INFRARED IMAGERY, SUPPORTED BY THE AFOREMENTIONED
ASCAT PASSES DEPICTING THE WESTERN SEMICIRCLE OF THE SYSTEM. POSITION
IS FURTHER SUBSTANTIATED BY THE CLUSTER OF PGTW, RJTD, KNES AND
RTCP AGENCY FIXES. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH
HIGH CONFIDENCE, CORROBORATED BY THE AFOREMENTIONED ASCAT PASSES
ALONG WITH TIGHT AGREEMENT BETWEEN AGENCY DVORAK ASSESSMENTS AND
OBJECTIVE SATELLITE ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: A 281136Z METOP-B ASCAT PASS AND AN
EARLIER 280412Z AMSR2 PASS

CURRENT STEERING MECHANISM: WEAK SUBTROPICAL RIDGING CENTERED TO
THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 35 KTS AT 281002Z
   CIMSS ADT: 32 KTS AT 281140Z
   CIMSS AIDT: 34 KTS AT 281140Z
   CIMSS D-MINT: 32 KTS AT 281001Z
   CIMSS D-PRINT: 37 KTS AT 281210Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL STORM 06W IS ANTICIPATED TO PROPAGATE
ON A GENERALLY NORTH-NORTHWESTWARD HEADING, STEERED BY THE
PERIPHERAL INFLUENCE OF A WEAK SUBTROPICAL RIDGE CENTERED TO THE
NORTHEAST. AS THIS ANTICYCLONE AMPLIFIES AND BECOMES THE DOMINANT
STEERING MECHANISM, TS JANGMI WILL ADVANCE TOWARD THE RIDGE AXIS,
FACILITATING CONTINUED CONSOLIDATION AND INTENSIFICATION. A STEADY
DEEPENING IS PROJECTED, CULMINATING IN A PEAK INTENSITY OF 95 KTS
NEAR TAU 72. BEYOND THIS PEAK, THE EVOLVING SYNOPTIC PATTERN WILL
FORCE A RECURVATURE, INDUCING A POLEWARD AND EASTWARD TURN BY TAU
96. DURING THIS LATTER PORTION OF THE FORECAST, THE SYSTEM WILL
COMMENCE A WEAKENING PHASE AS IT ENCOUNTERS A MORE HOSTILE
ENVIRONMENTAL REGIME, HIGHLIGHTED BY RAPIDLY COOLING SEA SURFACE
TEMPERATURES AND A SLIGHT INCREASE IN VERTICAL WIND SHEAR. AS TS
06W TRANSITS THE RYUKYU ARCHIPELAGO NEAR KADENA, REDUCED OCEANIC
HEAT CONTENT WILL ENHANCE THE PROBABILITY OF COLD WATER UPWELLING,
EXACERBATING THE RATE OF DECAY. BY TAU 120, AS THE SYSTEM
APPROACHES KYUSHU, A PRONOUNCED ENHANCEMENT IN POLEWARD OUTFLOW
DIVERGENCE WILL BE NEGATED BY DETERIORATING SEA SURFACE
TEMPERATURES PLUMMETING TO 24-25 C, ULTIMATELY RESULTING IN A RAPID
WEAKENING TREND.

MODEL DISCUSSION: NUMERICAL WEATHER PREDICTION TRACK GUIDANCE IS IN
FAIR AGREEMENT, WITH ALL DYNAMICAL AND EXPERIMENTAL AI MODELS
UNANIMOUSLY DEPICTING A RECURVATURE SCENARIO DICTATED BY THE
AMPLIFYING SUBTROPICAL RIDGE TO THE NORTHEAST. EXCLUDING THE
WESTWARD OUTLIER SOLUTION PROVIDED BY NAVGEM, THE REMAINDER OF THE
GUIDANCE ENVELOPE MAINTAINS A RELATIVELY TIGHT CLUSTERING,
EXHIBITING A CROSS-TRACK SPREAD OF 110 NM AROUND TAU 96. OVERALL
CONFIDENCE IN THE TRACK FORECAST REMAINS MEDIUM DUE TO THE
INCLUSION OF NAVGEM, WHICH EXPANDS THE FULL CONSENSUS SPREAD TO 165
NM BETWEEN TAU 96 AND TAU 120, COINCIDENT WITH THE CLOSEST POINT OF
APPROACH TO KADENA. THE OFFICIAL JTWC TRACK IS THEREFORE POSITIONED
SLIGHTLY EAST OF THE MULTI-MODEL CONSENSUS MEAN TO BETTER ALIGN
WITH THE HIGH-DENSITY MODEL CLUSTERING. REGARDING INTENSITY, ALL
AVAILABLE MODELS CONCUR ON THE OVERALL EVOLUTION, DEPICTING A
STEADY STRENGTHENING PHASE THROUGH TAU 72 FOLLOWED BY DECAY.
NEVERTHELESS, CONFIDENCE IN THE INTENSITY FORECAST REMAINS MEDIUM
DUE TO SIGNIFICANT DISPERSION IN PEAK AMPLITUDE. WHILE THE PEAK
INTENSITY GUIDANCE SPREAD HAS IMPROVED SINCE LAST FORECAST, THE
DETERMINISTIC GFS AND GFS-INITIALIZED COAMPS-TC REPRESENT THE UPPER
BOUND, PREDICTING 100-105 KTS, CONTRASTING WITH MORE CONSERVATIVE
PROJECTIONS FROM THE HAFS AND HWRF SOLUTIONS (75-80 KTS PEAK
INTENSITY). THE OFFICIAL JTWC INTENSITY FORECAST IS WEIGHTED TOWARD
THE MAJORITY GROUPING OF ENSEMBLE MEMBERS, PLACING IT SLIGHTLY
ABOVE THE MULTI-MODEL CONSENSUS.

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