WDPN32 PGTW 131500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (MAN-YI) WARNING NR 
019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 11.9N 141.2E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 242 NM WEST-SOUTHWEST OF ANDERSEN AFB
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A RATHER
SMALL, OBSCURED LOW LEVEL CIRCULATION CENTER (LLCC) WITH
DISORGANIZED CONVECTION DISPLACED TO THE SOUTHEAST OF THE LLCC. A
131212Z METOP-C AMSU-B 89GHZ MICROWAVE IMAGE REVEALED A SHALLOW
BANDING FEATURES WRAPPING INTO A DEFINED LLCC AND MODERATE
CONVECTION TO THE SOUTHEAST IN THE OUTER CONVERGENT BANDS. A
131116Z ASCAT-C PASS SHOWED A HIGHLY ASYMMETRIC CIRCULATION WITH
LIGHT WINDS TO THE SOUTH AND GALE-FORCE WINDS RESTRICTED TO THE
NORTHERN HEMISPHERE OF THE CIRCULATION. THE INITIAL POSITION IS
ASSESSED WITH HIGH CONFIDENCE BASED ON THE ASCAT DATA. THE INITIAL
INTENSITY IS ALSO ASSESSED WITH HIGH CONFIDENCE USING THE ASCAT
ULTRA-HIGH RESOLUTION WIND ANALYSIS. OVERALL, THE ENVIRONMENT IS
FAVORABLE, WITH VERY WARM SSTS, LOW VWS BUT ONLY WEAK RADIAL
OUTFLOW. THE ASYMMETRIC AND BROAD NATURE OF THE CIRCULATION IS ALSO
HINDERING DEVELOPMENT AT PRESENT.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHEASTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHWEST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T2.0 - 30 KTS
   CIMSS SATCON: 40 KTS AT 130949Z
   CIMSS ADT: 43 KTS AT 131130Z
   CIMSS AIDT: 37 KTS AT 131130Z
   CIMSS D-PRINT: 27 KTS AT 131300Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: WEAK RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL STORM (TS) 25W WILL CONTINUE TO TRACK
WEST-SOUTHWESTWARD ALONG THE SOUTHEASTERN SIDE OF THE STR FOR THE
NEXT 12 TO 18 HOURS. THE TRACK WILL GRADUALLY FLATTEN OUT TO A
WESTWARD TRACK BY TAU 24, AS THE STR CENTER MOVES EASTWARD TO A
POSITION DUE NORTH OF TS 25W BY TAU 36. BY TAU 48, THE RIDGE WILL
MOVES TO NEAR 140E, WITH THE PRIMARY STEERING AXIS SHIFTING TO THE
SOUTHWESTERN PERIPHERY. TS 25W WILL TURN GRADUALLY
WEST-NORTHWESTWARD BY TAU 48, THEN NORTHWESTWARD THROUGH THE
REMAINDER OF THE FORECAST PERIOD. THE TRACK HAS SHIFTED A BIT SOUTH
FROM THE PREVIOUS FORECAST AS THE RIDGE IS NOT EXPECTED TO PUSH AS
FAR TO THE EAST AS PREVIOUSLY FORECAST. ADDITIONALLY, A PASSING
TROF TO THE NORTH IS EXPECTED TO BE WEAKER AND NOT PENETRATE AS FAR
SOUTHWARD AS IN THE EARLIER FORECAST, THUS THE RIDGE IS FORECAST TO
REMAIN STRONGER TO THE NORTH AND PRECLUDE AS MUCH OF A
NORTH-NORTHWESTWARD TRACK. THE CURRENT FORECAST CALLS FOR LANDFALL
ON THE NORTHERN PORTION OF CATANDUANES ISLAND NEAR TAU 72. THE
SYSTEM THEN CONTINUES WEST-NORTHWESTWARD, CLOSE TO POLILLO ISLAND
AND INTO LUZON NEAR CABANATUAN CITY BY TAU 96 AND THENCE INTO THE
LINGAYEN GULF AND OUT INTO THE SOUTH CHINA SEA BY THE END OF THE
FORECAST. IN TERMS OF INTENSITY, THE SYSTEM WILL SLOWLY INTENSIFY
AT ROUGHLY THE CLIMATOLOGICAL RATE FOR THE FIRST 24 HOURS OF THE
FORECAST AS IT SLOWLY CONSOLIDATES UNDER GENERALLY FAVORABLE
CONDITIONS. THE SYSTEM IS FORECAST TO BECOME A TYPHOON BY TAU 36,
AND THEN RAPIDLY INTENSITY FROM THERE TO TAU 72 AS IT CROSSES OVER
AN AREA OF EXTREMELY HIGH OHC (OVER 175 KJ PER CM3) TO THE EAST OF
SAMAR ISLAND. TS 25W IS FORECAST TO REACH A PEAK OF AT LEAST 125
KNOTS BY TAU 72 BUT COULD EASILY REACH A HIGHER PEAK IN THE PERIOD
PRIOR TO THIS POINT. AFTER MAKING LANDFALL, THE SYSTEM WILL RAPIDLY
WEAKEN AS IT CROSSES OVER THE ISLANDS, EXPECTED TO EMERGE INTO THE
SOUTH CHINA SEA AS MINIMAL TYPHOON. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN GOOD AGREEMENT
ON THE OVERALL TRACK SCENARIO, WITH CROSS-TRACK SPREAD HAVING
DECREASED SINCE THE EARLIER RUN. CROSS-TRACK SPREAD AT LANDFALL
(TAU 72) IS 200NM, BETWEEN THE GFS TO THE NORTH KEEPING THE SYSTEM
WELL OFFSHORE AND THE UKMET ENSEMBLE MEAN TO THE SOUTH WHICH TAKES
THE SYSTEM OVER SAMAR AND MASBATE ISLAND. BY TAU 120, CROSS-TRACK
SPREAD INCREASES TO 450NM BETWEEN THE SAME TWO OUTLIERS. GFS MAKES
LANDFALL IN FAR NORTHEASTERN LUZON, WHILE THE UKMET ENSEMBLE
CROSSES THE SIBUYAN SEA, MINDORO ISLAND INTO THE SOUTH CHINA SEA.
ADDITIONALLY, THE SUPER ENSEMBLE, CONSISTING OF THE GEFS, ECENS,
CMC AND UKMET ENSEMBLES GENERALLY MIRRORS THE DETERMINISTIC
TRACKERS, WITH THE UKMET BEING THE SOUTHERN OUTLIER, AND GEFS TO
THE NORTH. THE MEAN OF THE MEANS LIES SLIGHTLY FURTHER SOUTH THAN
THE JTWC FORECAST, WHICH IS CLOSEST TO THE ECMWF ENSEMBLE AND
MULTI-MODEL CONSENSUS MEAN. CONFIDENCE IS HIGH TO TAU 72, THEN
MEDIUM. INTENSITY GUIDANCE IS IN GOOD AGREEMENT, IF A BIT TOO
AGGRESSIVE, WITH THE BULK OF THE GUIDANCE SHOWING RAPID
INTENSIFICATION FROM TAU 00, ALL THE WAY TO TAU 72. THE JTWC
FORECAST IS BELOW THE CONSENSUS MEAN TO TAU 48, THEN TRACES THE
HWRF TO THE PEAK AND THE MEAN TO TAU 120. THE CTCX ENSEMBLE
INTENSITY PROBABILITY PRODUCT SHOWS 90-95 PERCENT RI
PROBABILITIES, WITH A GREATER THAN 60 PERCENT CHANCE OF A SUPER
TYPHOON PRIOR TO LANDFALL, PROVIDING ADDITIONAL SUPPORT FOR THE
JTWC FORECAST WHICH EXPLICITLY CALLS FOR RI BETWEEN TAU 48 AND TAU
72. 

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