WDPN32 PGTW 221500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 24W (RAGASA) WARNING NR 
017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.4N 120.5E
   INITIAL INTENSITY: 130 KTS
   GEOGRAPHIC REFERENCE: 289 NM NORTH OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: WESTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: 48 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A LARGE
BANDING EYE FEATURE SLIGHTLY CONTRACTING AND BECOMING CLOUD-FILLED
AS SUPER TYPHOON (STY) 24W CONTINUES TRACKING WESTWARD INTO THE
SOUTH CHINA SEA. AN EYEWALL REPLACEMENT CYCLE (ERC) IS IN PROGRESS
AND THE FORMATION OF A SECONDARY EYEWALL IS EVIDENT IN A 221113Z
GPM GMI 89GHZ MICROWAVE IMAGE. THE INITIAL POSITION IS PLACED WITH
HIGH CONFIDENCE BASED ON THE AFOREMENTIONED EIR AND DOPPLER RADAR
REVEALING THE EYEWALL AND OUTER BANDS. THE INITIAL INTENSITY OF 130
KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY AND
OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: A SUBTROPICAL RIDGE TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.5 - 155 KTS
   RJTD: T7.0 - 140 KTS 
   RCTP: T7.5 - 155 KTS
   KNES: T7.5 - 155 KTS
   DEMS: T7.5 - 155 KTS
   CIMSS ADT: 129 KTS AT 221300Z
   CIMSS AIDT: 122 KTS AT 221300Z
   CIMSS D-MINT: 136 KTS AT 221113Z
   CIMSS D-PRINT: 129 KTS AT 221300Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: STY 24W WILL REMAIN UNDER THE STEERING
INFLUENCE OF THE SUBTROPICAL RIDGE TO THE NORTH. FOR THE NEST 36
HOURS. AFTER TAU 48, A BUILDING RIDGE TO THE NORTHEAST WILL ALTER
THE TRACK SLIGHTLY WESTWARD FOR THE REMAINDER OF THE FORECAST
PERIOD. STY 24W WILL GRADUALLY WEAKEN FOR THE NEXT 48 HOURS AS
UPWELLING AND INTERACTION WITH THE COASTLINE OF CHINA WEAKENS THE
STORM. GREATER TOPOGRAPHIC INTERACTION AT AND AFTER TAU 48 WITH THE
CHINESE COAST WILL INCREASE THE RATE OF WEAKENING. LANDFALL BETWEEN
TAU 48-72 ON THE NORTHERN COAST OF VIETNAM WILL LEAD THE STORM TO
DISSIPATION OVER LAND BY THE END OF THE FORECAST PERIOD.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT
THAT STY 24W WILL TRACK WEST-NORTHWESTWARD AND GRADUALLY CURVE
EITHER WESTWARD OR WEST-SOUTHWESTWARD BY THE END OF THE FORECAST
PERIOD DUE TO A BUILDING RIDGE OVER SOUTHWESTERN CHINA. THE
CROSS-TRACK SPREAD IS 164 NM BY THE END OF THE FORECAST PERIOD. IF
THE TRACK WAS TO LIE SLIGHTLY NORTH, THE WEAKENING RATE WOULD BE
GREATLY IMPACTED BY A LONGER TERM OF LAND INTERACTION. THE
INTENSITY GUIDANCE IS IN GOOD AGREEMENT, BUT BECAUSE OF THE
POSSIBILITY OF LAND INTERACTION WITH SLIGHT TRACK DEFLECTION, THE
LATE-TERM INTENSITY FORECAST CONFIDENCE IS SLIGHTLY LOWER THAN THE
NEAR-TERM.

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