Tropical Storm IN-FA Advisory Wed Jul 21

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (IN-FA) WARNING NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
   INITIAL POSITION: 24.1N 127.9E
   INITIAL INTENSITY: 95 KTS
   GEOGRAPHIC REFERENCE: 144 NM SOUTH OF KADENA AB, OKINAWA, JAPAN
   MOVEMENT PAST 6 HOURS: WESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 45 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM
CONTINUED TO INTENSIFY AS THE CENTRAL CONVECTION DEEPENED AND
FEEDER BANDS HAVE BECOME MORE COMPACT AND WRAPPED TIGHTER INTO A
DEFINED 24-NM EYE. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE EYE FEATURE IN THE MSI LOOP. THE INITIAL
INTENSITY OF 95 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON
OVERALL ASSESSMENT OF AGENCY DVORAK ESTIMATES AND THE ADT AND
REFLECTS THE SIGNIFICANT 6-HR INTENSIFICATION.
INITIAL WIND RADII BASIS: PERSISTENCE.
CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO
THE NORTH.
AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T5.0 - 90 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T5.0 - 90 KTS
   CIMSS SATCON: 97 KTS AT 202239Z
   CIMSS ADT: 107 KTS AT 202340Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD
ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TY IN-FA WILL CONTINUE WESTWARD TOWARD
NORTHERN TAIWAN UNDER THE STEERING INFLUENCE OF THE STR. AFTER TAU
48, IT WILL BEGIN TO ROUND THE SOUTHWESTERN EDGE OF THE STR AND
TURN NORTHWESTWARD, PASSING TO THE NORTH OF TAIWAN THEN MAKING
LANDFALL NEAR WENZHOU JUST BEFORE TAU 96. THE FAVORABLE ENVIRONMENT
WILL FUEL FURTHER INTENSIFICATION TO A PEAK OF 105KTS BY TAU 36.
AFTERWARD, INCREASING VWS, DRY AIR ENTRAINMENT, THEN LANDFALL INTO
CHINA WILL GRADUALLY THEN RAPIDLY ERODE THE SYSTEM DOWN TO 85KTS AT
TAU 72 AS IT PASSES TO THE NORTH OF TAIWAN, 55KTS AT LANDFALL, THEN
DOWN TO 30KTS BY TAU 120.
MODEL DISCUSSION: NUMERICAL MODELS ARE TIGHT UP TO TAU 72 WITH EVEN
AND GRADUAL SPREAD TO 130NM. AFTERWARD, THE MODELS DIVERGE FURTHER
TO OVER 320NM BY TAU 120 WITH UKMET ON THE LEFT AND ECMF ON THE
RIGHT MARGINS OF THE ENVELOPE. NOTABLY, NVGM DEFLECTS THE VORTEX
ABRUPTLY EASTWARD AFTER TAU 72.
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
NNNN
NNNN