WDPS31 PGTW 062100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 10P (NAT)        
WARNING NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.4S 155.9W
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 361 NM WEST OF PAPEETE, TAHITI
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A BROAD,
PARTIALLY EXPOSED LOW-LEVEL CIRCULATION (LLC) WITH LIMITED DEEP
CONVECTION SHEARED OVER THE EASTERN QUADRANT OF THE LLC. A FORTUITOUS 
061901Z ASCAT-B BULLSEYE IMAGE ALSO REVEALS A BROAD CENTER WITH 30-35 
KNOT WINDS. THERE IS NO RECENT MICROWAVE IMAGERY, THEREFORE THERE IS 
MEDIUM CONFIDENCE IN THE INITIAL POSITION. UPPER-LEVEL CONDITIONS 
REMAIN MARGINALLY FAVORABLE WITH WESTERLY VERTICAL WIND SHEAR OFFSET 
SLIGHTLY BY VIGOROUS POLEWARD OUTFLOW. THE INITIAL INTENSITY OF 45 KTS 
IS ASSESSED WITH MEDIUM CONFIDENCE HEDGED BELOW THE SUBJECTIVE DVORAK 
ESTIMATES IN CONSIDERATION OF THE RECENT ASCAT DATA AND THE CIMSS 
OBJECTIVE ESTIMATES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   NFFN: T3.5 - 55 KTS
   CIMSS ADT: 32 KTS AT 061940Z
   CIMSS DPRINT: 47 KTS AT 062000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 10P IS FORECASTED TO
TRACK GENERALLY EASTWARD ALONG THE SOUTHERN PERIPHERY OF THE NER
THROUGH THE FORECAST PERIOD. THE SYSTEM IS EXPECTED TO GRADUALLY
WEAKEN THROUGH THE FORECAST PERIOD WITH PERSISTENT MODERATE TO HIGH
VWS (20-25 KTS) AND DRY AIR ENTRAINMENT. THE SYSTEM IS EXPECTED TO
DISSIPATE BY TAU 48.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT
WITH A 130 NM TO 170 NM CROSS-TRACK SPREAD FROM TAU 36 TO TAU 48.
INTENSITY GUIDANCE IS IN POOR AGREEMENT WITH A LARGE SPREAD.
GENERALLY, SEVERAL OF THE MODELS INDICATE A REINTENSIFICATION PHASE
AFTER TAU 60, WITH HAFS-A SHOWING A PEAK OF 58 KNOTS AT TAU 60.
THIS REINTENSIFICATION PHASE IS ASSOCIATED WITH A STRONG
SUBTROPICAL LOW, WHICH COULD LEAD TO SUBTROPICAL TRANSITION NEAR
TAU 72.     

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