WDPN32 PGTW 280900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (SAOLA) WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.5N 124.3E
   INITIAL INTENSITY: 115 KTS
   GEOGRAPHIC REFERENCE: 258 NM NORTHEAST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 48 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS AN INTENSE
MEDIUM-SIZED, TIGHTLY WRAPPED, HIGHLY-SYMMETRICAL SYSTEM THAT HAS
MAINTAINED AN 8-NM, SHARPLY OUTLINED EYE. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON THE EYE. THE INITIAL INTENSITY OF 
115KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON OVERALL ASSESSMENT OF 
AGENCY DVORAK ESTIMATES AND REFLECTS THE SUSTAINED CONVECTIVE 
STRUCTURE. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH VERY WARM 
SST IN THE PHILIPPINE SEA, LOW VWS, AND MODERATE RADIAL OUTFLOW ALOFT, 
SLIGHTLY OFFSET BY LOCALIZED OCEAN UPWELLING.

INITIAL WIND RADII BASIS: PERSISTENCE.

CURRENT STEERING MECHANISM: EXTENSION OF A DEEP LAYER SUBTROPICAL
RIDGE (STR) TO THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T6.5 - 127 KTS
   CIMSS ADT: 84 KTS AT 280220Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TY SAOLA WILL CONTINUE TRACKING NORTHWARD
UNDER THE STR EXTENSION, THEN AFTER TAU 12, THE STR WILL BUILD AND 
DRIVE THE SYSTEM NORTHWESTWARD TOWARD TAIWAN VIA THE LUZON STRAIT, 
THEN WEST-NORTHWESTWARD AFTER TAU 72 ACROSS THE SOUTHERN PORTION OF 
THE TAIWAN STRAIT. THE FAVORABLE ENVIRONMENT, IMPROVED BY DIMINISHED 
UPWELLING, WILL FUEL STEADY INTENSIFICATION TO A PEAK OF 130KTS AT 
TAUS 24-36. AFTERWARD, INCREASING VWS AND LAND INTERACTION WILL 
GRADUALLY WEAKEN THE SYSTEM DOWN TO 60KTS BY TAU 120 AS IT APPROACHES 
EASTERN CHINA NORTHEAST OF HONG KONG. 


MODEL DISCUSSION: NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT
WITH A GRADUAL SPREAD TO JUST 120NM AT TAU 72 THEN MORE SIGNIFICANTLY 
TO 357NM AT TAU 120 WITH GFS THE LEFT-OF-TRACK OUTLIER AND JGSM ON THE 
RIGHT MARGIN AND DRIVING THE VORTEX DIRECTLY NORTHWARD INTO TAIWAN 
AFTER TAU 72. IN VIEW OF THESE, THERE IS OVERALL MEDIUM CONFIDENCE IN 
THE JTWC TRACK FORECAST UP TO TAU 72 THEN LOW CONFIDENCE AFTERWARD.  

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