WDPN31 PGTW 262100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 01W (EWINIAR) WARNING NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.5N 122.5E
   INITIAL INTENSITY: 85 KTS
   GEOGRAPHIC REFERENCE: 723 NM SOUTH-SOUTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON
(TY) 01W (EWINIAR) EXHIBITING A SMALL, COMPACT STRUCTURE WITH A 5NM
DIAMETER PINHOLE EYE FEATURE. MUCH OF THE OUTERMOST DEEP CONVECTIVE 
BANDS ASSOCIATED WITH TY 01W HAS BEEN REMOVED OVER THE PAST SIX HOURS 
DUE TO THE TOPOGRAPHICAL INFLUENCE OF LUZON, PHILIPPINES, AND A 
FURTHER DEVELOPED POLEWARD OUTFLOW CHANNEL IN THE NORTHWESTERN 
QUADRANT. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON 
A 261800Z HIMAWARI EIR SATELLITE IMAGE SHOWING AN EXPOSED EYE
FEATURE. THE INITIAL INTENSITY OF 85 KTS IS ASSESSED WITH MEDIUM 
CONFIDENCE BASED ON THE SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES 
LISTED BELOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A SUBTROPICAL
RIDGE.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   KNES: T5.0 - 90 KTS
   CIMSS ADT: 84 KTS AT 261730Z
   CIMSS AIDT: 84 KTS AT 261730Z
   CIMSS DPRINT: 75 KTS AT 261700Z
   CIMSS SATCON: 85 KTS AT 261700Z


FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 0-5 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE RADIAL

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: TY 01W IS FORECAST TO TRACK NORTH-NORTHEASTWARD 
ALONG THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE TO THE EAST FROM 
TAU 00 TO TAU 12. HAVING CROSSED OVER THE PHILIPPINES AND RETURNING TO 
VERY WARM OPEN WATER, ONSET OF RAPID INTENSIFICATION (RI) IS FORECAST 
AND LIKELY TO OCCUR, AS ALLUDED TO IN THE MODEL DISCUSSION BELOW. 
ROUNDING THE SUBTROPICAL RIDGE, TY 01W WILL TURN TO A MORE 
NORTHEASTWARD TRACK FOLLOWING TAU 12 AND MAINTAIN THIS TRACK THROUGH 
THE REMAINDER OF THE FORECAST PERIOD. RI IS ANTICIPATED TO CONTINUE 
THROUGH TAU 24 AS THE SYSTEM REALIZES A HIGHLY FAVORABLE ENVIRONMENT 
FOR FURTHER DEVELOPMENT. AS TY 01W PEAKS IN INTENSITY (115KTS AT TAU 
36), FALLING SEA SURFACE TEMPERATURES AND A SHARP DECREASE IN OCEAN 
HEAT CONTENT ARE FORECAST TO COMMENCE A WEAKENING TREND. TY 01W IS 
FORECAST TO BEGIN EXTRATROPICAL TRANSITION NEAR TAU 96 AND COMPLETE 
TRANSITION BY TAU 120.

MODEL DISCUSSION: GLOBAL NUMERICAL MODEL GUIDANCE IS IN EXCEPTIONAL
AGREEMENT REGARDING TRACK AND MODERATE AGREEMENT REGARDING
INTENSITY. A RELATIVELY SMALL CROSS-TRACK SPREAD OF 112NM IS
PRESENT BETWEEN JTWC CONSENSUS MEMBERS BY TAU 120, OFFSET BY
MODERATE DISAGREEMENT IN SUGGESTED TRACK SPEED, WITH A 450NM
ALONG-TRACK SPREAD BY TAU 120. MOST INTENSITY GUIDANCE ALIGNS WELL
WITH SEVERAL INDICATIONS OF RAPID INTENSIFICATION OCCURRING OVER THE
NEXT 24 HOURS. ADDITIONALLY, THE MAJORITY OF CONSENSUS MEMBERS
INCREASE IN INTENSITY TO A PEAK NEAR TAU 36, FOLLOWED BY A GRADUAL
WEAKENING TREND AS SEA SURFACE TEMPERATURES FALL AND VERTICAL 
WINDSHEAR INCREASES THEREAFTER. DESPITE GOOD AGREEMENT IN THE TIMING 
OF INCREASING AND DECREASING INTENSITY, A 40KTS INTENSITY SPREAD IS
PRESENT IN NUMERICAL MODEL GUIDANCE AT TAU 36, CONTRIBUTING TO AN
OVERALL INTENSITY FORECAST CONFIDENCE OF MEDIUM.

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