WDPS31 PGTW 070900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 23P (FILI) WARNING NR 
013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 23.1S 164.7E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 98 NM SOUTHWEST OF NOUMEA, NEW CALEDONIA
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHEASTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN EXPOSED,
WELL-DEFINED LOW-LEVEL CIRCULATION WITH DEEP CONVECTION SHEARED TO
THE EAST DUE TO HIGH SOUTHWESTERLY VERTICAL WIND SHEAR (VWS). THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MSI.
ALTHOUGH THE LLC IS EXPOSED, A 070537Z SSMIS 37GHZ MICROWAVE IMAGE
REVEALS A WELL-ORGANIZED LLC WITH CONVECTIVE BANDING WRAPPING INTO
A DEFINED CENTER. THE INITIAL INTENSITY OF 50 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON DVORAK CURRENT INTENSITY ESTIMATES
RANGING FROM 3.0-3.5, WHICH IS INLINE WITH THE 070313Z SATCON
ESTIMATE. 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: 3.0 - 45 KTS
   KNES: 3.0 - 45 KTS
   PHFO: 3.5 - 55 KTS
   CIMSS SATCON: 50 KTS AT 070313Z
   CIMSS ADT: 47 KTS AT 070540Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 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 36 HOURS. THE SYSTEM IS EXPECTED
TO TRANSITION TO A SUBTROPICAL CYCLONE BY TAU 36 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 36, THE EYSTEM WILL LIKELY SLOW AND BECOME
QUASI-STATIONARY AS A STRONG HIGH BUILDS TO THE SOUTH.    

MODEL DISCUSSION: THROUGH TAU 36, 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. OVERALL CONFIDENCE IN THE JTWC FORECAST
TRACK IS MEDIUM. INTENSITY GUIDANCE IS IN FAIR AGREEMENT WITH THE
BULK OF THE GUIDANCE MAINTAINING A 30-45 KNOT SYSTEM. DECAY SHIPS
GUIDANCE AND COAMPS-TC (NAVGEM VERSION) ARE DISSIPATING THE SYSTEM
AFTER TAU 36. 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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