WDPN31 PGTW 040300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (MATMO) WARNING NR 
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.2N 116.7E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 283 NM SOUTH-SOUTHEAST OF HONG KONG
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A BROAD
LOW-LEVEL CIRCULATION CENTER (LLCC), WITH FRAGMENTED DEEP CONVECTIVE 
BANDING WRAPPING INTO THE LLCC AND A DEVELOPING EYEWALL. A 032136Z 
GMI 37GHZ COLOR COMPOSITE MICROWAVE IMAGE REVEALS A SIGNIFICANTLY 
IMPROVED SYMMETRIC LOW-LEVEL CIRCULATION, WITH MULTIPLE CONVECTIVE 
BANDS WRAPPING TIGHTLY INTO AN ELONGATED BUT WELL-DEFINED MICROWAVE 
EYE FEATURE, WHICH SUPPORTS THE INITIAL POSITION WITH MEDIUM
CONFIDENCE. THE INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE HIGH END OF SUBJECTIVE DVORAK INTENSITY
ESTIMATES RANGING FROM 45-65 KNOTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T3.0 - 45 KTS
   RCTP: T3.5 - 55 KTS
   CIMSS SATCON: 55 KTS AT 032020Z
   CIMSS ADT: 37 KTS AT 040000Z
   CIMSS AIDT: 41 KTS AT 040000Z
   CIMSS D-MINT: 50 KTS AT 032133Z
   CIMSS D-PRINT: 50 KTS AT 040100Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TROPICAL STORM (TS) 27W IS FORECAST TO TRACK
WEST-NORTHWESTWARD THROUGH THE FORECAST PERIOD ALONG THE SOUTHERN
AND SOUTHWESTERN PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE.
TS 27W WILL INTENSIFY STEADILY THROUGH TAU 30 TO A PEAK INTENSITY
OF 85-90 KNOTS. ENVIRONMENTAL CONDITIONS ARE FAVORABLE THROUGH TAU
30, WITH LOW VERTICAL WIND SHEAR, RADIAL OUTFLOW AND WARM SST
VALUES. HOWEVER, THE SYSTEM IS FORECAST TO INTENSIFY AT A
CLIMATOLOGICAL RATE DUE TO THE BROAD NATURE OF THE LLCC AND THE
LIMITED TRACK OVER WATER. AFTER TAU 36, THE SYSTEM WILL WEAKEN
QUICKLY AS IT TRACKS OVER SOUTHERN CHINA, WITH DISSIPATION
ANTICIPATED BY TAU 72.   

MODEL DISCUSSION: DETERMINISTIC AND PROBABILISTIC MODEL GUIDANCE
REMAINS IN GOOD AGREEMENT THROUGH TAU 48, WITH A 65-90NM
CROSS-TRACK SPREAD FROM TAU 36 TO TAU 48. AFTER TAU 48, GUIDANCE
DIVERGES LENDING MEDIUM CONFIDENCE TO THE JTWC TRACK FORECAST.
RELIABLE INTENSITY GUIDANCE SUPPORTS A PERIOD OF RAPID
INTENSIFICATION THROUGH TAU 24, WITH PEAK INTENSITIES IN THE 
MESOSCALE GUIDANCE RANGING FROM 78 TO 82 KNOTS. 

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