WDPN33 PGTW 150900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W (NANMADOL) WARNING NR 011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 23.5N 137.9E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 578 NM EAST-SOUTHEAST OF KADENA AB,
OKINAWA, JAPAN
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A LARGE SYSTEM
WITH EXTENSIVE FEEDER BANDS TRAILING TO THE SOUTH ALL THE WAY TO
THE PHILIPPINES. THE CENTRAL CONVECTION HAS BECOME MORE
CONSOLIDATED AND HAS DEVELOPED A RAGGED, FORMATIVE EYE. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE FORMATIVE EYE
FEATURE IN THE MSI LOOP. THE INITIAL INTENSITY OF 65KTS IS ALSO
PLACED WITH HIGH CONFIDENCE BASED ON OVERALL ASSESSMENT OF AGENCY
AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE UPGRADE TO TYPHOON
INTENSITY. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW VWS
AND STRONG OUTFLOW OVER WARM SST.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA.

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T3.5 - 55 KTS
   CIMSS SATCON: 66 KTS AT 150358Z
   CIMSS ADT: 63 KTS AT 150540Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TY NANMADOL WILL CONTINUE WEST-NORTHWESTWARD
UNDER THE STEERING INFLUENCE OF THE STR TO THE NORTH. AFTER TAU 48,
IT WILL TURN MORE NORTHWESTWARD THEN AFTER TAU 72, WILL CREST THE
STR AXIS AND RECURVE NORTHEASTWARD, MAKE LANDFALL OVER KYUSHU,
JAPAN, NEAR SASEBO BY TAU 96. AFTERWARD, TY 16W WILL ACCELERATE
NORTHEASTWARD AND BY TAU 12O WILL BE IN THE SEA OF JAPAN (SOJ) JUST
OFF THE COAST OF HONSHU. THE FAVORABLE CONDITIONS WILL FUEL A
GRADUAL THEN RAPID INTENSIFICATION TO A PEAK OF 120KTS BY TAU 48 WITH 
THE ADDITION OF A POLEWARD OUTFLOW CHANNEL. AFTERWARD, INCREASING VWS,
LAND INTERACTION, THEN COOLING SST IN THE SOJ WILL GRADUALLY ERODE
THE SYSTEM. BY TAU 120, THE SYSTEM WILL BE REDUCED TO 55KTS AS IT
ENTERS THE BAROCLINIC ZONE AND BEGINS EXTRA-TROPICAL TRANSITION.   

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY GOOD AGREEMENT UP TO
TAU 72 WITH A GRADUAL AND EVEN SPREAD TO 130NM. AFTERWARD, THE
SPREAD INCREASES TO 400NM+ AT TAU 120 WITH NVGM THE ERRATIC
OUTLIER TO THE LEFT OF THE MAIN PACK IN THE MID-POTION AND THEN TO
THE RIGHT IN THE EXTENDED PORTION OF THE FORECAST. THERE IS ALSO
SIGNIFICANT ALONG TRACK VARIATIONS IN THE MODELS BEYOND TAU 72. IN
VIEW OF THIS, THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST
UP TO TAU 72 THEN LOW CONFIDENCE AFTERWARD. THERE IS MEDIUM
CONFIDENCE IN THE INTENSITY FORECAST UP TO TAU 72 WHERE THERE IS
SOME VARIABILITY IN THE PEAK INTENSITY, THEN LOW CONFIDENCE AFTER
TAU 72 DUE TO THE LARGE SPREAD AND VARIATIONS IN THE SPEEDS THAT
DIRECTLY AFFECT THE FORECAST INTENSITIES. 

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