WDPN31 PGTW 021500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (MATMO) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.2N 126.5E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 239 NM EAST-NORTHEAST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY REVEALS
INCREASINGLY ORGANIZED, DEEP CONVECTIVE CURVED BANDING GRADUALLY
WRAPPING INTO THE LOW-LEVEL CIRCULATION CENTER (LLCC) OF TROPICAL
STORM (TS) 27W (MATMO). THE SYSTEM IS EMBEDDED WITHIN A FAVORABLE
SYNOPTIC-SCALE ENVIRONMENT CHARACTERIZED BY ENHANCED RADIAL OUTFLOW
ENABLED BY UPPER-LEVEL DIVERGENCE, SEA SURFACE TEMPERATURES (SST)
RANGING BETWEEN 29-30 C, LOW (5-10 KTS) VERTICAL WIND SHEAR, AND A
MOIST TROPOSPHERIC COLUMN SUPPORTIVE OF SUSTAINED DEEP CONVECTION. 
THE INITIAL POSITION IS ESTIMATED WITH MEDIUM CONFIDENCE BASED ON THE 
PARTIAL EXPOSED LLCC PRESENT IN THE SHORTWAVE INFRARED SATELLITE 
IMAGERY LOOP. INITIAL INTENSITY IS ASSESSED AT 50 KTS WITH HIGH 
CONFIDENCE, SUPPORTED BY MULTIPLE SUBJECTIVE DVORAK FIXES AND 
OBJECTIVE SATELLITE-DERIVED ESTIMATES IN STRONG AGREEMENT.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) CENTERED TO THE
NORTH-NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T4.0 - 65 KTS
   CIMSS ADT: 41 KTS AT 021130Z
   CIMSS AIDT: 37 KTS AT 021130Z
   CIMSS D-PRINT: 48 KTS AT 021200Z

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

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TS 27W IS EXPECTED TO CONTINUE TRACKING 
NORTHWESTWARD UNDER THE STEERING INFLUENCE OF A PERSISTENT STR
POSITIONED TO THE NORTH. THE CYCLONE IS ANTICIPATED TO MAKE LANDFALL 
OVER CENTRAL-NORTHERN LUZON SHORTLY AFTER TAU 12. INTENSITY AT 
LANDFALL IS PROJECTED TO REACH 60-65 KTS, DUE TO THE CONTINUOUSLY 
FAVORABLE OCEANIC AND ATMOSPHERIC CONDITIONS. FOLLOWING LANDFALL, 
INTERACTION WITH RUGGED TERRAIN OVER LUZON WILL INDUCE FRICTIONAL 
DISRUPTION TO THE LOW-LEVEL INFLOW AND RESULT IN A DECREASE IN 
INTENSITY TO BELOW TYPHOON STRENGTH. SUBSEQUENTLY, THE SYSTEM IS 
FORECAST TO RE-EMERGE OVER THE SOUTH CHINA SEA AROUND TAU 24, WHERE 
SST VALUES REMAIN CONDUCIVE (28-29 C) FOR RE-INTENSIFICATION. AS THE 
STR AXIS SHIFTS EASTWARD, TS MATMO IS EXPECTED TO TRACK ALONG ITS 
SOUTHWESTERN PERIPHERY TOWARD THE CHINESE COASTLINE. THE SYNOPTIC 
ENVIRONMENT IS FORECAST TO REMAIN FAVORABLE FOR INTENSIFICATION, WITH 
PEAK INTENSITY EXPECTED TO REACH 70-75 KTS PRIOR TO FINAL LANDFALL. 
THE CURRENT TRACK FORECAST INDICATES A PRIMARY LANDFALL JUST NORTH OF
HAINAN ISLAND OVER THE LEIZHOU PENINSULA PRIOR TO TAU 72, FOLLOWED
BY A SECONDARY LANDFALL NEAR THE CHINA-VIETNAM BORDER BETWEEN TAUS
72 AND 96. AFTERWARDS, THE SYSTEM IS FORECAST TO WEAKEN STEADILY,
DUE TO INCREASING LAND INTERACTION, AND DISSIPATE PRIOR TO THE END
OF THE FORECAST PERIOD.

MODEL DISCUSSION: NUMERICAL GUIDANCE IS IN GENERAL CONSENSUS
REGARDING THE SYNOPTIC STEERING PATTERN AND OVERALL TRACK SCENARIO
THROUGHOUT THE FORECAST PERIOD. TRACK SPREAD AMONG CONSENSUS MEMBERS
IS APPROXIMATELY 20-25 NM PRIOR TO AND SHORTLY AFTER LUZON LANDFALL. 
BEYOND TAU 48, MODEL DISPERSION INCREASES SLIGHTLY NEAR THE CHINA 
COAST BUT REMAINS WITHIN A CROSS-TRACK ENVELOPE OF LESS THAN 80 NM 
THROUGH TAU 72. THE JTWC OFFICIAL TRACK FORECAST CLOSELY ALIGNS WITH 
THE MULTI-MODEL CONSENSUS AND IS POSITIONED ON THE NORTHERN EDGE OF 
THE GUIDANCE ENVELOPE. IN TERMS OF INTENSITY, THE FORECAST IS 
ASSESSED WITH MEDIUM CONFIDENCE DUE TO UNCERTAINTY IN LAND 
INTERACTION DURATION AND REEMERGENCE TIMING OVER OPEN WATER. 
FAVORABLE THERMODYNAMIC CONDITIONS - INCLUDING HIGH SST, ROBUST 
UPPER-LEVEL OUTFLOW, AND LOW VERTICAL SHEAR - WILL REMAIN IN PLACE 
THROUGH MOST OF THE FORECAST TRACK OVER THE SOUTH CHINA SEA. 
POTENTIAL FOR SHORT-TERM INTENSIFICATION IS LOWER THAN THAT OF THE 
PREVIOUS FORECAST, AS NONE OF THE RAPID INTENSIFICATION (RI) AIDS 
TRIGGERED THIS TIME. OVERALL FAVORABLE CONDITIONS WILL ALLOW THE 
SYSTEM TO REACH NEAR-TYPHOON STRENGTH AROUND TAU 12. SIMILARLY, JUST 
BEFORE TAU 72, SOME AIDS, INCLUDING HWRF AND DETERMINISTIC GFS, 
INDICATE POTENTIAL FOR THE MAXIMUM WINDS TO REACH 75 KTS. THE ONLY 
MAJOR INTENSITY MODEL OUTLIER IS CURRENTLY COAMPS-TC, WHICH PREDICTS 
A MUCH MORE SIGNIFICANT SPIKE IN PEAK INTENSITY (100-110 KTS) SHORTLY 
AFTER TAU 48.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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