WDPN32 PGTW 210900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 24W (RAGASA) WARNING NR 
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.3N 126.3E
   INITIAL INTENSITY: 140 KTS
   GEOGRAPHIC REFERENCE: 377 NM NORTHEAST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 37 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SUPER
TYPHOON (STY) 24W TRACKING WEST-NORTHWESTWARD WITH LOOPING
TROCHOIDAL MOTION. SYMMETRIC DEEP CONVECTION SURROUNDS A CLEAR EYE
FEATURE. ON WATER VAPOR IMAGERY UPPER-LEVEL OUTFLOW IS EXPANSIVE
BOTH POLEWARD AND EQUATORWARD. RAPID INTENSIFICATION HAS CONTINUED
OVER THE LAST SIX HOURS TO A PEAK OF 140KTS. THE INITIAL POSITION
IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED ANIMATED
MSI. THE INITIAL INTENSITY OF 140 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE AGENCY AND OBJECTIVE FIXES BELOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: A SUBTROPICAL RIDGE TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.0 - 140 KTS 
   RJTD: T6.5 - 127 KTS
   RCTP: T7.5 - 155 KTS
   KNES: T7.0 - 140 KTS 
   CIMSS SATCON: 142 KTS AT 210500Z
   CIMSS ADT: 140 KTS AT 210540Z
   CIMSS AIDT: 136 KTS AT 210540Z
   CIMSS D-MINT: 118 KTS AT 210500Z
   CIMSS D-PRINT: 124 KTS AT 210630Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 0-5 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 CONTINUE TO TRACK
WEST-NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF A SUBTROPICAL
RIDGE TO THE NORTH. AFTER TAU 72, A DIFFERENT SUBTROPICAL RIDGE
OVER LAND TO THE NORTH WILL CAUSE STY 24W TO CURVE
WEST-SOUTHWESTWARD. BETWEEN TAU 96 AND 120, THE SYSTEM WILL MAKE
LANDFALL ALONG THE NORTHERN COAST OF VIETNAM. THE SYSTEM WILL
REMAIN IN A HIGHLY FAVORABLE ENVIRONMENT FOR INTENSIFICATION WITH
HIGH OCEAN HEAT CONTENT OVER THE NEST 24 HOURS, ALLOWING FOR A PEAK
INTENSITY OF 145KTS. AS STY 24W TRACKS NORTH OF LUZON, THE SYSTEM
WILL WEAKEN SLIGHTLY DUE TO SIGNIFICANT UPWELLING AS THE SYSTEM
MOVES INTO AREAS OF LOWER OCEAN HEAT CONTENT. BY TAU 48, THE DEPTH
OF THE 26C ISOTHERM WILL DECREASE TO APPROXIMATELY 60M FROM
APPROXIMATELY 90M AT TAU 36. AS THE SYSTEM CONTINUES WESTWARD,
UPWELLING WILL CONTINUE TO WEAKEN THE STORM ALONG WITH TOPOGRAPHIC
INTERACTION WITH THE LEIZHOU PENINSULA. BY THE END OF THE FORECAST,
STY 24W WILL BE DISSIPATING OVER LAND IN LAOS.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN STRONG
AGREEMENT THAT STY 24W WILL CURVE WEST-NORTHWESTWARD AND THEN
WEST-SOUTHWESTWARD FOR THE REMAINDER OF THE FORECAST PERIOD. THE
CROSS-TRACK SPREAD IS 295NM. SLIGHT DEVIATIONS NORTH OR SOUTH
AFFECT THE INTENSITY GUIDANCE, WHICH HAS A LARGER SPREAD DEPENDING
ON WHETHER MODEL SOLUTIONS ANTICIPATE LANDFALL EARLIER OR LATER.

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