WDPN32 PGTW 160300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 25W (MAN-YI) WARNING NR 
029//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.5N 126.7E
   INITIAL INTENSITY: 130 KTS
   GEOGRAPHIC REFERENCE: 356 NM EAST-SOUTHEAST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 48 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SUPER
TYPHOON 25W (MAN-YI) WITH A NEARLY PERFECTLY SYMMETRICAL EYE AND
A VERY WELL-DEFINED CENTRAL DENSE OVERCAST OVER THE EYEWALL.
ENVIRONMENTAL ANALYSIS INDICATES THAT 25W IS IN A HIGHLY FAVORABLE
ENVIRONMENT CHARACTERIZED BY STRONG RADIAL OUTFLOW ALOFT, LOW (0-5
KTS) VERTICAL WIND SHEAR, AND WARM (29-30 C) SEA SURFACE
TEMPERATURES. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON THE CLEAR EYE IN THE ANIMATED MSI. THE INITIAL INTENSITY
OF 130 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY
DVORAK INTENSITY ESTIMATES OF T6.5-7.0. ADDITIONALLY, RAW T VALUES
FROM CIMSS ADT HAVE STAYED RIGHT AROUND 6.9 FOR THE PAST 4 HOURS,
SUPPORTING THE SUPER TYPHOON INTENSITY.

INITIAL WIND RADII BASIS: AMSR2 WIND SPEED IMAGE

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A
DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE
NORTH-NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.5 - 127 KTS
   RJTD: T6.5 - 127 KTS
   RCTP: T7.0 - 140 KTS 
   KNES: T6.5 - 127 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE INTENSITY THROUGH TAU 24 IS
INCREASED FROM THE PREVIOUS FORECAST. 

FORECAST DISCUSSION: 25W IS FORECAST TO CONTINUE TRACKING
WEST-NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF THE STR
THROUGH TAU 36 WITH LANDFALL EXPECTED NEAR TAU 30 IN LUZON. AFTER
THE VORTEX EMERGES WITHIN THE SOUTH CHINA SEA, RIDGING EXTENDING
WESTWARD AND NORTH OF THE SYSTEM WILL CONTINUE TO DRIVE IT FURTHER
WESTWARD. ADDITIONALLY, AN INCOMING COLD SURGE WILL PREVENT THE
SYSTEM FROM GAINING LATITUDE. AROUND TAU 96, THE WEAKENED SYSTEM
WILL BEGIN TO TRACK SOUTHWESTWARD, ALONG THE LOW-LEVEL STEERING
PATTERN, THROUGH THE REMAINDER OF THE FORECAST PERIOD. REGARDING
INTENSITY, 25W IS FORECAST TO MAINTAIN SUPER TYPHOON INTENSITY OVER
THE NEXT 12 HOURS DUE TO THE CONTINUED HIGHLY CONDUCIVE ENVIRONMENT. 
AFTER TAU 12, INTERACTION WITH THE ISLANDS OF THE PHILIPPINES WILL 
SLIGHTLY WEAKEN THE SYSTEM AS IT APPROACHES LUZON. AFTER LANDFALL, A 
BORDERLINE TYPHOON IS EXPECTED TO ENTER THE SOUTH CHINA SEA WHERE THE 
ENVIRONMENT WILL BE UNFAVORABLE DUE TO INCREASING VERTICAL WIND SHEAR 
ALONG WITH THE DRY AND COLD AIR BEING BROUGHT IN FROM THE COLD SURGE. 
AS A RESULT, 25W IS EXPECTED TO STEADILY WEAKEN TO AROUND 40 KTS AT 
TAU 96. AFTER TAU 96, THE ENVIRONMENT QUICKLY WORSENS FURTHER WITH 
SHEAR INCREASING UPWARDS OF 30 KTS AND VAST AMOUNTS OF DRY AIR 
ENTRAINMENT. AS A RESULT, THE SYSTEM IS EXPECTED TO DISSIPATE AROUND 
THE END OF THE FORECAST PERIOD SOUTH OF HAINAN.


MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN VERY GOOD AGREEMENT 
THROUGH TAU 72 WITH A 38 NM CROSS-TRACK SPREAD AT TAU 30, NEAR THE 
TIME OF LANDFALL. AFTER TAU 72, CROSS-TRACK AND ALONG-TRACK SPREAD 
INCREASES DUE TO THE WEAKENING VORTEX AND VARIANCE IN THE TIMING OF 
DISSIPATION. THE JTWC TRACK FORECAST IS PLACED CLOSE TO CONSENSUS 
THROUGH THE ENTIRE FORECAST WITH HIGH CONFIDENCE THROUGH TAU 72 AND 
MEDIUM CONFIDENCE THEREAFTER. INTENSITY GUIDANCE CONTINUES TO BE 
SPLIT. THE GFS AND HWRF BOTH DEPICT RAPID, AND SOMEWHAT UNREALISTIC, 
WEAKENING THROUGH TAU 24. ON THE OTHER HAND, HAFS-A AND COAMPS-TC 
DEPICT A STEADY INTENSITY THOUGH TAU 24. THE JTWC INTENSITY FORECAST 
IS PLACED CLOSER TO THE LATTER GROUPING AND THEN CLOSE TO CONSENSUS 
AFTER TAU 24 WITH OVERALL MEDIUM CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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