WDXS32 PGTW 231500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 22S (HALIMA) WARNING 
NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.3S 75.8E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 420 NM SOUTH-SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
MEDIUM-SIZED, ELONGATED, AND CONSOLIDATING SYSTEM WITH DISORGANIZED 
AND FRAGMENTED FORMATIVE BANDS FEEDING INTO A DEEPENING CENTRAL
CONVECTION THAT IS OBSCURING THE LOW LEVEL CIRCULATION (LLC). THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE
RAGGED BUT DEFINED LLC FEATURE IN THE 230857Z AMSR2 89GHZ IMAGE.
THE INITIAL INTENSITY OF 35KTS IS BASED WITH MEDIUM CONFIDENCE ON
THE FMEE DVORAK ESTIMATE OF T2.5 AND FROM THE 230855Z 
GCOMW1.AMSR2.WINDSPEED DATA SHOWING A 37KT PIXEL. ANALYSIS INDICATES 
A FAVORABLE ENVIRONMENT WITH LOW VWS, STRONG POLEWARD OUTFLOW, AND 
WARM ALONG-TRACK SST. THE CYCLONE IS TRACKING ALONG THE NORTHWEST 
PERIPHERY OF THE STR TO THE SOUTHEAST.

INITIAL WIND RADII BASIS: GCOMW1.AMSR2.WINDSPEED DATA.

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
SOUTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   FMEE: T2.5 - 35 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TC HALIMA WILL CONTINUE ON A SOUTHWESTWARD
TRACK UNDER THE STR TO THE SOUTHEAST UP TO TAU 24. AFTERWARD, IT
WILL BEGIN TO ROUND THE STR AXIS AND TRACK MORE SOUTHWARD, THEN BY
TAU 72, SOUTHEASTWARD. THE FAVORABLE CONDITIONS WILL CARRY THROUGH
TAU 48 AND FUEL A GRADUAL THEN RAPID INTENSIFICATION TO A PEAK OF
85KTS, POSSIBLY HIGHER. AFTER TAU 48, INCREASING VWS AND COOLING
SST WILL GRADUALLY ERODE THE SYSTEM DOWN TO 60KTS BY TAU 120.   

MODEL DISCUSSION: NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT
WITH A GRADUAL AND EVEN SPREAD TO 204NM BY TAU 72. AFTERWARD THE
MODELS SIGNIFICANTLY DIVERGE WITH THE MAJORITY INDICATING A
REVERSAL IN STORM MOTION. IN VIEW OF THIS, THERE IS MEDIUM
CONFIDENCE IN THE JTWC TRACK AND INTENSITY FORECASTS UP TO TAU 72
THEN LOW CONFIDENCE AFTERWARD. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
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