WDPS31 PGTW 071500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 23P (FILI) WARNING NR 
014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 23.9S 164.8E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 130 NM SOUTH-SOUTHWEST OF NOUMEA, NEW
CALEDONIA
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 21 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN
EXPOSED, WELL-DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH DEEP
CONVECTION SHEARED TO THE EAST. A 071042Z AMSU 89GHZ MICROWAVE
IMAGE DEPICTS SHALLOW BANDING WRAPPING TIGHTLY INTO A
WEAKLY-DEFINED LLCC. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE EIR IMAGERY AND THE AMSU IMAGE. THE INITIAL
INTENSITY OF 45 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE
PGTW AND PHFO DVORAK CURRENT INTENSITY ESTIMATES OF 3.0 (45 KNOTS).
UPPER-LEVEL ANALYSIS INDICATES AN UNFAVORABLE ENVIRONMENT WITH HIGH
VWS AND MODERATE EASTWARD OUTFLOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A
DEEP-LAYERED SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T2.5 - 35 KTS
   PHFO: T3.0 - 45 KTS
   CIMSS SATCON: 51 KTS AT 070734Z
   CIMSS ADT: 37 KTS AT 071140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 25-30 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: MODERATE EASTWARD
   OTHER FACTORS: SIGNIFICANT DRY AIR ENTRAINMENT IN THE MID TO
LOWER LEVELS. 

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: TC 23P IS TRACKING ALONG THE SOUTHWESTERN
PERIPHERY OF THE STR AND IS INTERACTING WITH THE SUBTROPICAL
WESTERLIES RESULTING IN LIMITED OUTFLOW AND HIGH VWS, WHICH WILL
SERVE TO GRADUALLY WEAKEN THE SYSTEM AS IT TRACKS SOUTHEASTWARD TO
EAST-SOUTHEASTWARD OVER THE NEXT 24 HOURS. THE SYSTEM IS EXPECTED
TO TRANSITION TO A SUBTROPICAL CYCLONE BY TAU 24 UNDER
STRENGTHENING WESTERLIES AND INCREASING (40 KNOTS) VWS WITH
SIGNIFICANT DRY AIR ENTRAINMENT AND UPPER-LEVEL CONVERGENT FLOW.
THE SYSTEM SHOULD MAINTAIN GALE-FORCE WINDS OVER THE SOUTHERN
SEMICIRCLE. AFTER TAU 24, THE SYSTEM WILL LIKELY SLOW AND BECOME
QUASI-STATIONARY FOR 1 TO 2 DAYS AS A STRONG HIGH BUILDS TO THE
SOUTH.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
THROUGH TAU 24 WITH INCREASING UNCERTAINTY AFTER TAU 24 DUE TO THE
ERRATIC, QUASI-STATIONARY MOTION ANTICIPATED AS THE STRONG HIGH
BUILDS IN TO THE SOUTH. OVERALL CONFIDENCE IN THE JTWC FORECAST
TRACK IS MEDIUM. INTENSITY GUIDANCE IS IN FAIR AGREEMENT WITH THE
BULK OF THE GUIDANCE MAINTAINING A 30-48 KNOT SYSTEM. DECAY SHIPS
GUIDANCE DISSIPATES THE SYSTEM BY TAU 24. OVERALL CONFIDENCE IN THE
JTWC INTENSITY FORECAST IS MEDIUM.  

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