WDXS32 PGTW 190900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 06S (ANGGREK)    
WARNING NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.4S 92.9E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 232 NM WEST OF THE COCOS ISLANDS
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 21 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
DESPITE SOME DRY AIR OVER THE SOUTHERN SEMICIRCLE, WHICH IS HINDERING 
CONVECTIVE DEVELOPMENT, THE SYSTEM HAS STRENGTHENED NOTICEABLY OVER 
THE PAST 12 HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) 
DEPICTS DEEP CONVECTIVE BANDING, PRIMARILY IN THE NORTHERN 
SEMICIRCLE, WRAPPING INTO A COMPACT CORE, WITH A DEVELOPING EYE. A 
190324Z MHS 89 GHZ MICROWAVE IMAGE REVEALS A PARTIAL EYEWALL OVER THE 
NORTHERN QUADRANT WITH A WEAKER, FRAGMENTED EYEWALL OVER THE SOUTHERN 
QUADRANT. EQUATORWARD OUTFLOW IS ROBUST AS IS EVIDENT ON THE ANIMATED 
WATER VAPOR LOOP. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE 
BASED ON EXTRAPOLATION FROM A BULLSEYE 190327Z ASCAT-B IMAGE. THE 
INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED 
ON AN AVERAGE OF THE SUBJECTIVE DVORAK ESTIMATES. CIMSS OBJECTIVE 
ESTIMATES ARE SLIGHTLY LOWER. 

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: WEAK SUBTROPICAL RIDGE (STR) POSITIONED
TO THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T4.0 - 65 KTS
   APRF: T3.5 - 55 KTS
   CIMSS ADT: 53 KTS AT 190600Z
   CIMSS AIDT: 56 KTS AT 190600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG EQUATORWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT OVER THE SOUTHERN SEMICIRCLE

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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) 06S IS TRACKING SLOWLY
ALONG THE NORTHERN PERIPHERY OF THE STR AND IS FORECASTED TO TURN
SLOWLY WEST-NORTHWESTWARD AS THE STR REORIENTS AFTER TAU 24. AFTER
TAU 72, THE STEERING ENVIRONMENT BECOMES COMPLEX WITH RIDGING
SURROUNDING THE SYSTEM, CAUSING A VERY SLOW, ERRATIC TRACK IN THE 
LATER TAUS. TC 06S WILL MAINTAIN INTENSITY AT 60 KNOTS THROUGH TAU 12 
THEN WEAKEN STEADILY THROUGH THE FORECAST PERIOD DUE TO AN INCREASE 
IN DRY AIR ENTRAINMENT. 

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT
THROUGH TAU 72 WITH MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST. 
HOWEVER, AFTER TAU 72 BOTH THE ENSEMBLE MODELS (GEFS AND EPS) AND
DETERMINISTIC TRACKERS INDICATE HIGH UNCERTAINTY WITH ERRATIC
QUASI-STATIONARY TRACKS. THE JTWC INTENSITY FORECAST IS SUPPORTED BY 
THE HAFS-A AND COAMPS-TC (GFS VERSION) GUIDANCE. 

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