WDPN31 PGTW 042100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 27W (MATMO) WARNING NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.8N 112.8E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 169 NM SOUTH-SOUTHWEST OF HONG KONG
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 33 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS RAPIDLY 
CYCLING DEEP CONVECTION ROTATING AROUND A LARGE, OBLONG EYE. ANIMATED 
RADAR IMAGERY REVEALS MULTIPLE, FRAGMENTED SPIRAL BANDS WITH A LARGE 
SYMMETRIC EYE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE 
BASED ON THE EIR SATELLITE AND RADAR IMAGERY. ENVIRONMENTAL ANALYSIS 
INDICATES A FAVORABLE ENVIRONMENT, WITH LOW VERTICAL WIND SHEAR, 
RADIAL OUTFLOW AND WARM SST VALUES. THE INITIAL INTENSITY OF 80 KTS 
IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE HIGH END OF AGENCY 
ESTIMATES AND A 041800Z DPRINT ESTIMATE OF 83 KNOTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
ENTRENCHED TO THE NORTH AND NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T3.5 - 55 KTS
   KNES: T5.0 - 90 KTS
   CIMSS SATCON: 71 KTS AT 041800Z
   CIMSS ADT: 55 KTS AT 041800Z
   CIMSS AIDT: 61 KTS AT 041800Z
   CIMSS D-PRINT: 83 KTS AT 041800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

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: TYPHOON (TY) 27W IS FORECAST TO TRACK WEST-
NORTHWESTWARD THROUGH THE FORECAST PERIOD. TY 27W WILL INTENSIFY DUE 
TO THE FAVORABLE CONDITIONS THROUGH TAU 12 TO A PEAK INTENSITY OF 90 
KNOTS. AFTER TAU 12, THE SYSTEM WILL TRACK OVER THE LEIZHOU PENINSULA 
THEN INLAND OVER SOUTHERN CHINA WITH RAPID WEAKENING. THE SYSTEM IS 
EXPECTED TO DISSIPATE BY TAU 48.

MODEL DISCUSSION: DETERMINISTIC AND PROBABILISTIC MODEL GUIDANCE 
REMAINS IN GOOD AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC TRACK 
FORECAST. RELIABLE INTENSITY GUIDANCE SUPPORTS THE JTWC INTENSITY 
FORECAST WITH MEDIUM CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: MEDIUM//
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