WTPQ31 RJTD 211800
RSMC TROPICAL CYCLONE PROGNOSTIC REASONING
REASONING NO.20 FOR TY 2518 RAGASA (2518)
1.GENERAL COMMENTS
  TY RAGASA IS LOCATED AT 19.1N, 124.1E. INFORMATION ON THE CURRENT
  POSITION IS BASED ON THE EYE IN ANIMATED MSI AND SURFACE
  OBSERVATIONS. POSITIONAL ACCURACY IS GOOD. CENTRAL PRESSURE IS
  925HPA AND MAXIMUM SUSTAINED WINDS NEAR THE CENTER ARE 100KNOTS.
  THE SYSTEM IS IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT UNDER THE
  INFLUENCE OF HIGH SSTS, HIGH TCHP, WEAK VWS AND GOOD UPPER-LEVEL
  OUTFLOW. HOWEVER, THE INSUFFICIENT ENVIRONMENT FOR ITS FURTHER
  DEVELOPMENT HAS CAUSED IT TO MAINTAIN ITS INTENSITY OVER THE LAST
  SIX HOURS. INFORMATION ON THE CURRENT INTENSITY IS BASED ON DVORAK
  INTENSITY ANALYSES AND SURFACE OBSERVATIONS.
2.SYNOPTIC SITUATION
  THE SYSTEM IS MOVING WESTWARD ALONG THE SOUTHERN PERIPHERY OF A
  MID-LEVEL SUB-TROPICAL HIGH. ANIMATED MSI SHOWS THE SYSTEM HAS AN
  EYE. ANIMATED MSI SHOWS THE CLOUD CHARACTERISTICS OF ANTICYCLONIC
  OUTFLOW ARE NOW DISTINCT. NOAA-21/ATMS 85 GHZ MICROWAVE IMAGERY
  SHOWS THE SYSTEM HAS AN EYE.
3.TRACK FORECAST
  THE SYSTEM WILL MOVE WESTWARD ALONG THE PERIPHERY OF A MID-LEVEL
  SUB-TROPICAL HIGH UNTIL FT120. THE SYSTEM WILL HIT VIET-NAM BY
  FT96. THE TRACK FORECAST IS BASED ON GSM PREDICTIONS, AND
  REFERENCE TO OTHER NWP MODELS. TRACK FORECAST CONFIDENCE IS HIGH
  BECAUSE ALL NWP MODELS ARE IN CLOSE AGREEMENT.
4.INTENSITY FORECAST
  THE SYSTEM WILL DEVELOP UNTIL FT12 DUE TO THE INFLUENCE OF
  INTERACTION WITH HIGH SSTS, HIGH TCHP, WEAK VWS AND GOOD
  UPPER-LEVEL OUTFLOW. THE SYSTEM WILL THEN GRADUALLY WEAKEN UNTIL
  FT72 DUE TO THE INFLUENCE OF INTERACTION WITH HIGH SSTS AND LAND.
  THE SYSTEM WILL THEN WEAKEN RAPIDLY UNTIL FT120 DUE TO ITS
  LANDFALL. THE SYSTEM WILL WEAKEN TO TD INTENSITY BY FT120. THE
  INTENSITY FORECAST IS BASED ON A CONSENSUS OF GUIDANCE DATA
  INCLUDING GSM.
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