WDPN31 PGTW 141500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 28W (RAI) WARNING NR 
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 8.5N 134.5E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 72 NM NORTH OF KOROR, PALAU
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
SIX-HOUR ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS
THE SYSTEM HAS MAINTAINED OVERALL CONVECTIVE SIGNATURE. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A MICROWAVE EYE
FEATURE. IN THE 140938Z SSMIS 91GHZ IMAGE. THE INITIAL INTENSITY OF
55KTS IS PLACED WITH MEDIUM CONFIDENCE BASED ON AGENCY AND
AUTOMATED DVORAK ESTIMATES AND CONSISTENT WITH THE ONSET OF A
MICROWAVE EYE FEATURE. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT
WITH LOW VWS, STRONG OUTFLOW, AND WARM SST IN THE PHILIPPINE SEA.
THE
CYCLONE IS TRACKING ALONG THE SOUTHERN PERIPHERY OF THE STR TO THE
NORTH.

INITIAL WIND RADII BASIS: RECENT SCATTEROMETER DATA. 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.5 - 55 KTS
   CIMSS ADT: 57 KTS AT 140840Z

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

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: TS RAI WILL CONTINUE ON ITS CURRENT TRACK,
MAKING LANDFALL OVER SURIGAO, PHILIPPINES, JUST AFTER TAU 48, DRAG
ACROSS THE ARCHIPELAGO, AND EXIT INTO THE SOUTH CHINA SEA (SCS)
SHORTLY AFTER TAU 72. THE FAVORABLE ENVIRONMENT WILL FUEL GRADUAL
THEN RAPID INTENSIFICATION TO 95KTS BY TAU 48. AFTERWARD,
INTERACTION WITH THE PHILIPPINE ISLANDS WILL SLIGHTLY ERODE THE
SYSTEM TO 90KTS AS IT EXITS INTO THE SCS. THE WARM SST IN THE SCS
AND CONTINUED LOW VWS, AND GOOD POLEWARD OUTFLOW WILL PROMOTE A
PEAK OF 105KTS BY TAO 96. AFTERWARD, THE INFLUX OF COLD DRY AIR
ASSOCIATED WITH A NORTHEASTERLY WIND SURGE IN THE SCS WILL BEGIN TO 
WEAKEN THE SYSTEM DOWN TO 90KTS BY TAU 120. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT
LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST UP TO TAU 120.
THERE IS MEDIUM CONFIDENCE IN THE INTENSITY FORECAST UP TO TAU 72
THEN LOW CONFIDENCE AFTERWARD.

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