WDPS31 PGTW 021500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 15P (JUDY) WARNING NR 
015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 24.2S 174.7E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 420 NM SOUTH-SOUTHWEST OF SUVA, FIJI
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 39 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A
MEDIUM-SIZED SYSTEM HAS BEGUN TO GRADUALLY WEAKEN AS EVIDENCED BY
WARMING AND UNRAVELING CENTRAL CONVECTION. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON THE WELL-DEFINED LOW LEVEL
CIRCULATION FEATURE IN THE 020950Z AND 021036Z ASCAT BULLSEYE
PASSES. THE INITIAL INTENSITY IS BASED ON THE LOW END OF AGENCY AND
AUTOMATED DVORAK ESTIMATES AND REFLECTS THE 6-HR EIR DEGRADATION.
ANALYSIS INDICATES AN UNFAVORABLE ENVIRONMENT WITH STRONG OUTFLOW
OFFSET BY STRONG VERTICAL WIND SHEAR AND COOLING SST.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA.

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO
THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   KNES: T5.0 - 90 KTS
   PHFO: T5.5 - 102 KTS
   CIMSS SATCON: 87 KTS AT 020858Z
   CIMSS ADT: 79 KTS AT 021130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 30+ KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC JUDY WILL CONTINUE TO TRACK SOUTHEASTWARD
UNDER THE STEERING STR. THE UNFAVORABLE ENVIRONMENT WILL SLOWLY
THEN RAPIDLY ERODE THE SYSTEM DOWN TO 50KTS BY TAU 36. CONCURRENTLY
BY TAU 24, TC 15P WILL BEGIN SUBTROPICAL TRANSITION AND BY TAU 36, 
WILL TRANSFORM INTO A SUBTROPICAL LOW WITH AN EXPANDING WIND FIELD.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT WITH
A GRADUAL AND EVEN SPREAD TO 155NM BY TAU 36, LENDING HIGH CONFIDENCE 
TO THE JTWC TRACK FORECAST. THERE IS OVERALL MEDIUM CONFIDENCE IN THE 
INTENSITY FORECAST DUE TO THE VARIABILITY INTRODUCED BY SUBTROPICAL 
TRANSITION.

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