WDPN31 PGTW 230900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 19W (KAJIKI)      
WARNING NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.6N 115.0E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 397 NM EAST-NORTHEAST OF DA NANG, VIETNAM
   MOVEMENT PAST 6 HOURS: WESTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 21 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AS INDICATED IN ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI), 
MODERATE (15-20 KTS) EASTERLY VERTICAL WIND SHEAR (VWS) IS HINDERING 
DEVELOPMENT, WITH A PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION 
INCREASINGLY EVIDENT ALONG THE EASTERN EDGE OF THE CORE CONVECTION. 
HIGH RESOLUTION MICROWAVE IMAGERY HAS BEEN SPARSE. HOWEVER, A 230455Z 
ATMS 88.2GHZ MICROWAVE IMAGE REVEALS DEEP CONVECTIVE BANDING WRAPPING 
INTO THE LLC, WITH AN INTENSE CORE OF CENTRAL CONVECTION SHEARED TO 
THE WEST. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED 
ON MSI. WITH THE EXCEPTION OF THE EASTERN QUADRANT, UPPER-LEVEL 
OUTFLOW IS ROBUST, WITH STRONG EQUATORWARD OUTFLOW AND IMPROVING 
POLEWARD OUTFLOW DRIVING THE IMPROVED CENTRAL CONVECTION. 
CONSEQUENTLY, SUBJECTIVE DVORAK ESTIMATES HAVE INCREASED TO T3.5 TO 
T4.0. CIMSS OBJECTIVE ESTIMATES HAVE GRADUALLY INCREASED TO AS HIGH 
AS 49 KNOTS. THE INITIAL INTENSITY OF 50 KTS IS ASSESSED WITH MEDIUM 
CONFIDENCE BASED ON THE PGTW AND KNES ESTIMATES TEMPERED BY THE CIMSS 
OBJECTIVE ESTIMATES.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
ENTRENCHED TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T3.5 - 55 KTS
   CIMSS SATCON: 48 KTS AT 230630Z
   CIMSS ADT: 49 KTS AT 230630Z
   CIMSS AIDT: 41 KTS AT 230630Z
   CIMSS D-MINT: 43 KTS AT 230545Z
   CIMSS D-PRINT: 39 KTS AT 230630Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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) 19W IS FORECAST TO TRACK 
WESTWARD ALONG THE SOUTHERN PERIPHERY OF THE STR THROUGH THE FORECAST 
PERIOD, SKIRTING THE SOUTHERN COAST OF HAINAN ISLAND FROM TAU 24 TO 
TAU 30. AS VWS ABATES OVER THE NEXT 12 HOURS, TS 19W IS FORECAST TO 
INTENSIFY STEADILY TO A PEAK INTENSITY OF 75 KNOTS BY TAU 36 ASSUMING 
THE CORE OF THE SYSTEM STAYS SOUTH OF HAINAN AS INDICATED BY HAFS-A. 
AFTER TAU 36, UPWELLING COOLER WATER SHOULD CONTRIBUTE TO A SLIGHT 
WEAKENING TREND JUST PRIOR TO LANDFALL. AFTER TAU 48, THE SYSTEM WILL 
RAPIDLY WEAKEN OVERLAND AND DISSIPATE BY TAU 72.  

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE REMAINS IN TIGHT 
AGREEMENT THROUGH THE FORECAST PERIOD, WITH A 60-75NM CROSS-TRACK 
SPREAD FROM TAU 36 TO TAU 48. THE 221800Z ECEPS AND 230000Z GEFS 
ENSEMBLES ALSO REMAIN IN GOOD AGREEMENT LENDING HIGH CONFIDENCE TO 
THE JTWC TRACK FORECAST. RELIABLE DETERMINISTIC INTENSITY GUIDANCE 
INDICATES MODERATE POTENTIAL FOR RAPID INTENSIFICATION (RI), WITH 
PEAK INTENSITY VALUES RANGING FROM 65 TO 90 KNOTS NEAR TAU 36. 
ADDITIONALLY, RI GUIDANCE IS TRIGGERED SUGGESTING CONDUCIVE 
CONDITIONS THROUGH TAU 48. THE 221800Z COAMPS-TC INTENSITY ENSEMBLE 
(CTCXEPS) INDICATES A 30-40 PERCENT PROBABILITY OF RI THROUGH TAU
36 WHILE THE SYSTEM TRACKS SOUTH TO SOUTHWEST OF HAINAN ISLAND. 

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