WDPN32 PGTW 070900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 32W (FUNG-WONG) WARNING 
NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 11.6N 136.6E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 929 NM EAST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: WESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 29 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
STORM 32W (FUNG-WONG) WITH A MORE COMPACT INNER-CORE AND DEEP
CONVECTION TIGHTLY WRAPPING AROUND ALL SIDES. A 070703Z F18 SSMIS
37 GHZ MICROWAVE IMAGE REVEALED THAT A LARGE MICROWAVE EYE FEATURE
HAS FORMED AT THE LOWER LEVELS. THE 91 GHZ VERSION OF THE SAME
IMAGE SHOWS A WELL-DEVELOPED BAND OF CONVECTION WITHIN THE SOUTHERN
SEMICIRCLE, OUTLINING THE LOW-LEVEL CIRCULATION CENTER (LLCC). THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE
ANIMATED MSI, AND SUPPORTED BY THE SSMIS IMAGES. THE INITIAL
INTENSITY OF 60 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED
PRIMARILY ON THE AGENCY DVORAK FIXES OF T3.5-4.0. THE CIMSS
OBJECTIVE INTENSITY ESTIMATES ARE A BIT LOWER, IN THE 45-55 KNOT
RANGE. ENVIRONMENTAL ANALYSIS INDICATES THAT 32W IS IN A HIGHLY
FAVORABLE ENVIRONMENT CHARACTERIZED BY STRONG RADIAL OUTFLOW ALOFT,
LOW (5-10 KTS) VERTICAL WIND SHEAR, AND WARM (29-30 C) SEA SURFACE
TEMPERATURES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK AND PERSISTENCE

CURRENT STEERING MECHANISM: RIDGING EXTENDING TO NORTH OF THE
SYSTEM

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T4.0 - 65 KTS
   CIMSS SATCON: 54 KTS AT 070610Z
   CIMSS ADT: 55 KTS AT 070610Z
   CIMSS AIDT: 46 KTS AT 070610Z
   CIMSS D-MINT: 52 KTS AT 070702Z
   CIMSS D-PRINT: 56 KTS AT 070610Z

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

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: 32W IS FORECAST TO TRACK WEST-NORTHWESTWARD
UNDER THE INFLUENCE OF A BUILDING SUBTROPICAL RIDGE TO THE
NORTHEAST. THIS RIDGE IS EXPECTED TO FOLLOW THE SYSTEM WESTWARD AND
EVENTUALLY ANCHOR NEAR 20N 140E. 32W WILL TRACK ALONG THE
SOUTHWESTERN PERIPHERY OF THE RIDGE THROUGH TAU 72. LANDFALL WITHIN
LUZON IS FORECAST TO OCCUR AROUND TAU 60, JUST SOUTH OF CASIGURAN.
THE SYSTEM WILL THEN EMERGE WITHIN THE SOUTH CHINA SEA AND BEGIN TO
ROUND THE WESTERN EXTENT OF THE SUBTROPICAL RIDGE. A NORTH
NORTHWARD TRACK IS FORECAST THROUGH THE REMAINDER OF THE FORECAST
PERIOD WITH RATHER SLOW TRACKS SPEEDS DUE TO COMPETING STEERING
WITH A SEPARATE RIDGE THAT WILL BE CENTERED OVER HAINAN. A FINAL
LANDFALL IS EXPECTED TO OCCUR WITHIN SOUTHERN TAIWAN JUST AFTER TAU
120. IN TERMS OF INTENSITY, 32W IS FORECAST TO RAPIDLY INTENSIFY
THROUGH TAU 36 TO AROUND 115 KTS. THE INTENSIFICATION TREND WILL
THEN HALT AS EASTERLY SHEAR BEGINS TO INCREASE TO AROUND 25-30 KTS.
AN INTENSITY OF 115 KTS IS CURRENTLY FORECAST FOR THE TIME OF
LANDFALL IN LUZON. AFTER MAKING LANDFALL, THE MOUNTAINOUS TERRAIN
WILL RAPIDLY WEAKEN THE VORTEX. ONCE THE SYSTEM ENTERS THE SOUTH
CHINA SEA REDEVELOPMENT WILL BE HINDERED BY INCREASING SOUTHERLY
SHEAR AND DRY AIR. AS A RESULT, 32W IS FORECAST TO WEAKEN THROUGH
THE REMAINDER OF THE FORECAST PERIOD AS IT TRACKS TOWARD SOUTHERN
TAIWAN.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE CONTINUES TO BE IN
VERY GOOD AGREEMENT THROUGH TAU 72, WITH THE EXCEPTION OF NAVGEM
WHICH TRACKS THE VORTEX MUCH FURTHER. DISCOUNTING NAVGEM, THERE IS
A 115 NM CROSS-TRACK SPREAD AT TAU 72, LENDING HIGH CONFIDENCE IN
THE JTWC TRACK FORECAST THROUGH THAT TIME. AFTER TAU 72, MODELS
BEGIN TO DIVERGE WITH VARYING SHARPNESS OF THE NORTHWARD TURN. GFS
HAS THE WIDEST TURN WHILE GALWEM HAS THE SHARPEST. CROSS-TRACK
SPREAD INCREASES SIGNIFICANTLY TO 405 NM AT TAU 120. THE JTWC TRACK
FORECAST FOLLOWS MORE CLOSELY TO THE ECMWF AND AI SOLUTIONS THROUGH
TAU 120 WITH MEDIUM CONFIDENCE. INTENSITY GUIDANCE OVERALL AGREES
ON RAPID INTENSIFICATION (RI) THROUGH TAU 36, WITH NEARLY ALL
AVAILABLE RI AIDS TRIGGERING THIS MODEL RUN. PEAK INTENSITIES RANGE
FROM 100-120 KTS WITH HAFS-A BEING THE MOST AGGRESSIVE MODEL.
MODELS THEN AGREE ON RAPID WEAKENING THROUGH TAU 72 AND MORE
GRADUAL WEAKENING THROUGH TAU 120. THE JTWC INTENSITY FORECAST
FOLLOWS CLOSELY TO THE HAFS-A DUE TO THE EXPECTATION OF RAPID
DEVELOPMENT UNDER THE EFFECTS OF THE HIGHLY FAVORABLE ENVIRONMENT. 


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