WDXS31 PGTW 040300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 23S (HIDAYA) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 7.9S 40.8E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 110 NM SOUTHEAST OF DAR ES SALAAM,
TANZANIA
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE SYSTEM
HAS RAPIDLY ERODED AS IT APPROACHED TANZANIA OVER THE LAST 12
HOURS. CONVECTIVE ACTIVITY HAS SHRUNK AND CLOUD TOPS HAVE CONSIDERABLY 
WARMED. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON 
A NOTCH FEATURE, REMNANT OF AN OBSCURED EYE, IN THE EIR LOOP. THE 
INITIAL INTENSITY OF 55KTS IS BASED ON THE LOW END OF AGENCY AND 
AUTOMATED DVORAK ESTIMATES, EXTRAPOLATED FROM THE 031905Z 
SCATTEROMETRY DATA, AND CONSISTENT WITH THE RAPID DECAY. ANALYSIS 
INDICATES AN UNFAVORABLE ENVIRONMENT WITH THE WARM SST OVER THE SOUTH 
INDIAN OCEAN AND MODERATE OUTFLOW OFFSET BY MODERATE VWS, LAND 
INTERACTION AND DRY AIR INTRUSION FROM THE AFRICAN CONTINENT.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: LOW- TO MID-LEVEL REFLECTION OF THE
SUBTROPICAL RIDGE (STR) TO THE SOUTH-SOUTHWEST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   DEMS: T4.5 - 77 KTS
   FMEE: T4.0 - 65 KTS
   CIMSS SATCON: 53 KTS AT 032330Z
   CIMSS ADT: 59 KTS AT 032330Z
   CIMSS AIDT: 57 KTS AT 032330Z
   CIMSS DPRINT: 40 KTS AT 040000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: AS TC HIDAYA CONTINUES TO ERODE AND LOSE
VERTICAL STRUCTURE, IT WILL TRACK MORE NORTHWESTWARD WITH THE LOW
LEVEL WIND FLOW, MAKING LANDFALL JUST SOUTH OF DAR ES SALAAM
SHORTLY AFTER TAU 12, THEN TRACK ALONG THE TANZANIAN COAST. THE
UNFAVORABLE ENVIRONMENT, EXACERBATED BY FRICTIONAL EFFECTS, WILL
LEAD TO DISSIPATION BY TAU 24, POSSIBLY SOONER. 

MODEL DISCUSSION: NUMERICAL MODELS SPREAD OUT WIDELY AND
ERRATICALLY AFTER TAU 12, LEADING TO MEDIUM CONFIDENCE ON THE JTWC
TRACK FORECAST THAT IS LAID CLOSE TO THE CONSENSUS. 

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