WDPN32 PGTW 052100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 28W (HALONG) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.5N 141.9E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 599 NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 23 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A 
CONSOLIDATING LOW-LEVEL CIRCULATION, WITH A DEVELOPING CENTRAL DENSE 
OVERCAST AND CONVECTIVE BANDING OVER THE NORTHERN SEMICIRCLE. UPPER-
LEVEL OUTFLOW HAS IMPROVED QUICKLY, WITH RADIAL OUTFLOW EVIDENT IN 
ANIMATED WATER VAPOR IMAGERY. A 051643Z AMSR2 36GHZ MICROWAVE IMAGE 
SHOWS A DEVELOPING EYEWALL SURROUNDING A SMALL, WELL-DEFINED 
MICROWAVE EYE FEATURE, WHICH SUPPORTS THE INITIAL POSITION WITH HIGH 
CONFIDENCE. THE INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH MEDIUM 
CONFIDENCE BASED ON THE PGTW AND KNES DVORAK ESTIMATES AS WELL AS THE 
CIMSS SATCON, ADT AND AIDT ESTIMATES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: COMPETING STEERING INFLUENCE, WITH A 
BROAD SUBTROPICAL RIDGE (STR) TO THE WEST AND ANOTHER BROAD STR TO 
THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T2.5 - 35 KTS
   KNES: T3.5 - 55 KTS
   CIMSS SATCON: 56 KTS AT 051626Z
   CIMSS ADT: 55 KTS AT 051730Z
   CIMSS AIDT: 55 KTS AT 051730Z
   CIMSS D-MINT: 46 KTS AT 051626Z
   CIMSS D-PRINT: 47 KTS AT 051810Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE 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: TROPICAL STORM (TS) 28W IS LOCATED WITHIN A
COMPETING STEERING ENVIRONMENT AND IS TRACKING SLOWLY WEST-
NORTHWESTWARD. TS 28W IS FORECAST TO TRACK ALONG THE WESTERN 
PERIPHERY OF THE EASTERN DOMINANT STR, WITH A GRADUAL TURN TO A 
NORTHWESTWARD TO NORTHWARD TRACK BY TAU 72. TS 28W WILL UNDERGO RAPID 
INTENSIFICATION (RI) THROUGH TAU 48, WITH A PEAK INTENSITY OF 125 
KNOTS OR HIGHER DUE TO VERY FAVORABLE ENVIROMENTAL CONDITIONS. AFTER 
TAU 72, THE SYSTEM WILL RECURVE SHARPLY EAST-NORTHEASTWARD AND 
COMMENCE EXTRA-TROPICAL TRANSITION (ETT) BY TAU 96. EXPANSIVE GALE-
FORCE WINDS ARE EXPECTED ACROSS THE KANTO PLAIN REGION AS THE SYSTEM 
TRACKS PAST NEAR TAU 84. AFTER TAU 96, TS 28W WILL BECOME EMBEDDED IN 
THE MIDLATITUDE WESTERLIES, GAINING FRONTAL CHARACTERISTICS AND 
COMPLETING ETT BY TAU 120.       

MODEL DISCUSSION: DETERMINISTIC GUIDANCE IS NOW IN SIGNIFICANTLY 
IMPROVED AGREEMENT, WITH ALL MODELS DEPICTING A SHARP RECURVATURE 
WELL SOUTH OF MAINLAND JAPAN. THE CROSS-TRACK SPREAD RANGES FROM 180-
230 NM NEAR THE RECURVE POINT AT TAU 72 NARROWING TO 130NM BY TAU 96. 
THE 051200Z EPS AND GEFS ENSEMBLES INDICATE GOOD AGREEMENT, WITH THE 
VAST MAJORITY OF SOLUTIONS SOUTH OF THE KANTO PLAIN DUE TO THE 
PRESENCE OF STRONG UPPER-LEVEL WESTERLIES OVER CENTRAL JAPAN. 
RELIABLE INTENSITY GUIDANCE SUPPORTS THE RI FORECAST, WITH HAFS-A AND 
COAMPS-TC (GFS) PEAKING THE INTENSITY FROM 125 TO 135 KNOTS AT TAU 
72. ADDITIONALLY, THE 051200Z COAMPS-TC (GFS) INTENSITY ENSEMBLE 
INDICATES A 70-90 PERCENT PROBABILITY OF RAPID
INTENSIFICATION (RI) FROM TAU 48 TO TAU 84.

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