WDPN31 PGTW 151500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (RAI) WARNING NR 011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 9.4N 130.0E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 613 NM EAST-SOUTHEAST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
DEEPENING SYSTEM WITH A MORE SYMMETRICAL CENTRAL CONVECTION. THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A
150925Z SSMIS 91GHZ MICROWAVE EYE. THE INITIAL INTENSITY OF 80KTS
IS BASED ON AN OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK
ESTIMATES (SEE BELOW) AND REFLECTS THE IMPROVED STATE OF THE
SYSTEM. TY 28W IS IN A FAVORABLE ENVIRONMENT WITH LOW VWS, VERY WARM 
SST IN THE PHILIPPINE SEA, AND STRONG POLEWARD AND EQUATORWARD 
OUTFLOW. THE CYCLONE IS TRACKING ALONG THE SOUTHERN PERIPHERY OF THE 
DEEP-LAYER STR TO THE NORTH.

INITIAL WIND RADII BASIS: RECENT SCATTEROMETER DATA ADJUSTED FOR
INCREASED INTENSITY. 

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO
THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T5.0 - 90 KTS
   KNES: T5.0 - 90 KTS
   CIMSS SATCON: 74 KTS AT 151312Z
   CIMSS ADT: 84 KTS AT 151140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TYPHOON RAI WILL CONTINUE ON ITS WESTWARD
TRACK, MAKING LANDFALL OVER SURIGAO, PHILIPPINES AROUND TAU 18 THEN
TRACK ACROSS THE PHILIPPINE ARCHIPELAGO. BY TAU 48, THE SYSTEM WILL
ENTER THE SOUTH CHINA SEA (SCS) AND TURN MORE NORTHWESTWARD THEN
NORTHWARD AS IT ROUNDS THE WESTERN EDGE OF THE STR. THE FAVORABLE
ENVIRONMENT WILL FUEL A SLIGHT INTENSIFICATION TO 85KTS JUST BEFORE
LANDFALL. AFTERWARD, INTERACTION WITH THE ISLANDS WILL REDUCE IT TO
70KTS BY TAU 36. AFTER IT DRIFTS INTO THE OPEN WARM WATERS OF THE
SCS, AIDED BY INCREASED POLEWARD OUTFLOW, A SECONDARY
INTENSIFICATION TO A PEAK OF 95KTS BY TAU 72 WILL OCCUR. AFTER TAU
72, INCREASING VWS AND EXPOSURE TO THE DRY NORTHEAST SURGE IN THE
SCS WILL RAPIDLY WEAKEN THE SYSTEM DOWN TO 45KTS BY TAU 120 AS IT
HEADS TOWARD HAINAN.

MODEL DISCUSSION: NUMERICAL MODELS REMAIN IN VERY TIGHT AGREEMENT;
HOWEVER, DUE TO THE TRACK VARIABILITY INTRODUCED BY LAND
INTERACTION AND THE DRY NORTHEAST SURGE IN THE SCS, THERE IS ONLY
MEDIUM CONFIDENCE IN THE JTWC TRACK AND INTENSITY FORECASTS.


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