WDXS31 PGTW 271500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05S (FIVE) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.5S 96.4E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 33 NM SOUTHWEST OF THE COCOS ISLANDS
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) O5S IS INDUBITABLY ON A STEADY WEAKENING TREND 
AS INDICATED IN THE ANIMATED ENHANCED INFRARED (EIR) SATELLITE 
IMAGERY. DEEP CONVECTION HAS FRAGMENTED AND IS NOW SHEARED OVER THE 
WESTERN SEMICIRCLE OF A PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION 
CENTER (LLCC). A 271204Z SSMIS 91GHZ COLOR COMPOSITE MICROWAVE IMAGE 
REVEALS SHALLOW BANDING OVER THE SOUTHERN SEMICIRCLE WRAPPING INTO 
THE WESTERN QUADRANT OF A WEAKLY-DEFINED LLCC, WITH SPARSE, 
DISORGANIZED CONVECTION. THE INITIAL POSITION IS PLACED ON THE 
NORTHERN EDGE OF THE SHALLOW CURVED BAND WITH MEDIUM CONFIDENCE. 
ENVIRONMENTAL CONDITIONS HAVE DEGRADED WITH HIGH (25-30 KNOTS) 
EASTERLY TO EAST-NORTHEASTERLY VERTICAL WIND SHEAR (VWS) OFFSET 
SLIGHTLY BY MODERATE POLEWARD OUTFLOW. THE INITIAL INTENSITY IS
ASSESSED AT 35 KNOTS ON THE HIGH END OF THE SUBJECTIVE DVORAK
ESTIMATES RANGING FROM 30-35 KNOTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: LOW-LEVEL NEAR-EQUATORIAL RIDGE (NER)
POSITIONED TO THE NORTH AND NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.0 - 30 KTS
   DEMS: T2.5 - 35 KTS
   CIMSS SATCON: 44 KTS AT 271207Z
   CIMSS ADT: 34 KTS AT 271200Z
   CIMSS AIDT: 32 KTS AT 271200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TC 05S IS CURRENTLY TRANSITIONING FROM THE NER
TO THE LOW-LEVEL SUBTROPICAL RIDGE (STR) BUILDING TO THE EAST.
THEREFORE, THE SYSTEM IS TURNING ONTO A MORE SOUTHEASTWARD
TRAJECTORY OVER THE PAST SIX HOURS. TC 05S IS FORECASTED TO TRACK
GENERALLY SOUTHWARD THROUGH THE FORECAST PERIOD UNDER THE STEERING
INFLUENCE OF THE STR TO THE EAST. THE SYSTEM WILL LIKELY RE-
STRENGTHEN BRIEFLY DIURNALLY BEFORE SIGNIFICANT WEAKENING OCCURS. TC 
05S WILL DISSIPATE NO LATER THAN TAU 36 BUT COULD POSSIBLY DISSIPATE 
AT AN EARLIER TIME DUE TO PERSISTENT VWS AND DRY AIR ENTRAINMENT.         

MODEL DISCUSSION: DETERMINISTIC AND PROBABILISTIC GUIDANCE IS IN
TIGHT AGREEMENT THROUGH TAU 24 THEN DIVERGES QUICKLY AFTER TAU 24,
WITH INCREASING HIGH UNCERTAINTY IN THE TIMING OF THE SHARP
WESTWARD TURN UNDER THE LOW-LEVEL HIGH TO THE SOUTH. RELIABLE
INTENSITY GUIDANCE IS IN FAIR AGREEMENT WITH THE STEADY WEAKENING
TREND THROUGH THE FORECAST PERIOD.   

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