WDXS31 PGTW 162100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 01S (ONE) WARNING NR 
001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 9.8S 89.8E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 442 NM WEST-NORTHWEST OF THE COCOS ISLANDS
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS
PARTIALLY EXPOSED CYCLONIC TURNING INTO A LOW-LEVEL CIRCULATION
CENTER, 15-20KT VERTICAL WIND SHEAR DISPLACES THE DEEP CONVECTION
SOUTHWEST OF THE CENTER. WATER VAPOR IMAGERY REVEALS MODERATE POLEWARD
OUTFLOW INTO A JET MAXIMA TO THE SOUTH. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON A 161601Z METOP-C ASCAT WIND
VECTOR IMAGE REVEALING THE CIRCULATION CENTER CLOSED AT THE CENTER
IDENTIFIED ON EIR. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH
HIGH CONFIDENCE BASED ON THE AFOREMENTIONED SCATTEROMETRY WHILE
SUPPORTED BY THE AGENCY AND OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: 161601Z METOP-C ASCAT DATA

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   DEMS: T2.5 - 35 KTS
   FMEE: T2.0 - 30 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 01S WILL TRACK
WEST-SOUTHWESTWARD OVER THE NEXT 36 HOURS. BETWEEN TAU 36-72, THE 
SYSTEM WILL CURVE SOUTHWESTWARD AS IT BEGINS TO ROUND THE PERIPHERY OF 
THE SUBTROPICAL RIDGE TO THE SOUTH. SLIGHT INTENSIFICATION IS 
ANTICIPATED IN THE NEAR-TERM AS THE SYSTEM REMAINS IN WARM SEA SURFACE 
TEMPERATURES, FAVORABLE UPPER-LEVEL DIFFLUENCE, AND 10-15KT WIND 
SHEAR, REACHING A PEAK INTENSITY OF 40KTS BY TAU 36. VERTICAL WIND 
SHEAR WILL INCREASE UNFAVORABLY ABOVE 20KTS AFTER TAU 36, INITIATING A 
PERIOD OF WEAKENING. ULTIMATELY, TROPICAL CYCLONE (TC) 01S WILL 
DISSIPATE BELOW WARNING THRESHOLD BY TAU 72.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT
THAT TC 01S WILL TRACK OVERALL SOUTHWESTWARD FOR THE REMAINDER OF
THE FORECAST PERIOD. THE CROSS-TRACK SPREAD OF 150NM BY THE END OF
THE FORECAST PERIOD. THE ENSEMBLE SOLUTIONS BETWEEN GEFS AND ECENS
ALSO SUPPORT THE SOUTHWESTWARD TRACK. THE INTENSITY GUIDANCE IS
CONSISTENT WITH A PEAK BETWEEN 35-40KTS BETWEEN TAU 24-48. THE
ENSEMBLE MEMBERS IN GEFS CONSISTENTLY INDICATE A PEAK OF 30-40KTS,
WHILE FEW ECENS SOLUTIONS PEAK ABOVE 40KTS. 

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