WDPN31 PGTW 010300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 12W (HINNAMNOR) WARNING 
NR 016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.6N 125.8E
   INITIAL INTENSITY: 140 KTS
   GEOGRAPHIC REFERENCE: 258 NM SOUTH-SOUTHWEST OF KADENA AB,
OKINAWA, JAPAN
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 53 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A HIGHLY
SYMMETRICAL COMPACT SYSTEM WITH SHORT FEEDER BANDS THAT CONTINUED
TO DEEPEN AND MAINTAIN A WELL-DEFINED 18-NM EYE. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE FEATURE IN
THE MSI LOOP AND ALSO IN THE COMPOSITE RADAR LOOP FROM JMA. THE
INITIAL INTENSITY IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON
EQUALLY-VALUED AGENCY AND AUTOMATED DVORAK ESTIMATES AND CONSISTENT
WITH THE 6-HR DEEPENING. THE ENVIRONMENT REMAINS FAVORABLE WITH LOW
VWS, STRONG RADIAL OUTFLOW AND WARM SSTS.

INITIAL WIND RADII BASIS: PERSISTENCE FROM RECENT SCATTEROMETER
DATA AND SURFACE WIND OBSERVATIONS. 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO
THE NORTHWEST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.0 - 140 KTS 
   RJTD: T7.0 - 140 KTS 
   CIMSS SATCON: 144 KTS AT 312022Z
   CIMSS ADT: 140 KTS AT 312340Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 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: STY HIMMNAMNOR WILL BEGIN TO SLOW DOWN THEN
BECOME QUASI-STATIONARY (QS) AS A BUILDING STR TO THE NORTHWEST AND
A NEAR EQUATORIAL RIDGE COMPETE FOR STEERING AGAINST THE CURRENT
STEERING STR TO THE NORTH THAT WILL WEAKEN AND RECEDE EASTWARD WITH
THE APPROACH OF A MID-LATITUDE TROUGH FROM THE WEST. AFTER TAU 48,
THE CURRENT STR, NOW POSITIONED TO THE NORTHEAST WILL RE-BUILD AND
REGAIN STEERING, DRIVING THE SYSTEM NORTHWARD THEN
NORTH-NORTHEASTWARD TOWARD THE KOREA STRAIT. COOLING SST DUE TO
UPWELLING DURING THE QS STATE WILL SLIGHTLY WEAKEN THE CYCLONE TO
100KTS. AFTERWARD, AS IT BEGINS TO TRACK NORTHWARD, WARM SST AND
INCREASED POLEWARD OUTFLOW WILL FUEL A SECONDARY INTENSIFICATION TO
115KTS AT TAUS 72-96. AFTER TAU 96, INCREASING VWS AND COOLING SST
WILL BEGIN TO ERODE THE SYSTEM, DOWN TO 95KTS BY TAU 120 AS IT
ENTERS THE KOREA STRAIT.

MODEL DISCUSSION: NUMERICAL MODELS NOW IN TIGHT AGREEMENT WITH A
GRADUAL END EVEN SPREAD TO 210NM BY TAU 120. THERE ARE DIFFERENCES
IN SPEED ALONG TRACK ESPECIALLY ON THE DURATION OF QS STATE. IN
VIEW OF THIS, THERE IS ONLY MEDIUM CONFIDENCE IN THE JTWC TRACK
FORECAST THAT IS LAID NEAR THE MODEL CONSENSUS. THE INTENSITY
FORECAST CONFIDENCE IS ALSO MEDIUM TO TAU 72 THEN LOW AFTERWARD.   

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