WTPQ31 RJTD 031800
RSMC TROPICAL CYCLONE PROGNOSTIC REASONING
REASONING NO.12 FOR STS 2411 YAGI (2411)
1.GENERAL COMMENTS
  STS YAGI IS LOCATED AT 18.9N, 117.9E. INFORMATION ON THE CURRENT
  POSITION IS BASED ON ANIMATED MSI AND SURFACE OBSERVATIONS.
  POSITIONAL ACCURACY IS FAIR. CENTRAL PRESSURE IS 985HPA AND
  MAXIMUM SUSTAINED WINDS NEAR THE CENTER ARE 55KNOTS. THE SYSTEM IS
  IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT UNDER THE INFLUENCE OF
  HIGH SSTS, HIGH TCHP AND GOOD UPPER-LEVEL OUTFLOW. THIS HAS CAUSED
  THE SYSTEM TO DEVELOP 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 SLOWLY NORTH-NORTHWESTWARD ALONG THE
  SOUTHWESTERN PERIPHERY OF A MID-LEVEL SUB-TROPICAL HIGH. ANIMATED
  MSI SHOWS CB CLUSTERS GATHERING AROUND THE CSC AND FORMING A
  CURVED BAND. ANIMATED MSI SHOWS GOOD CLOUD CHARACTERISTICS OF
  ANTICYCLONIC OUTFLOW. GCOM-W/AMSR2 89 GHZ MICROWAVE IMAGERY SHOWS
  THE SYSTEM HAS A BAND WITH CURVATURE INDICATING THE CSC.
3.TRACK FORECAST
  THE SYSTEM WILL MOVE WEST-NORTHWESTWARD ALONG THE PERIPHERY OF A
  MID-LEVEL SUB-TROPICAL HIGH UNTIL FT24. THE SYSTEM WILL THEN MOVE
  WESTWARD ALONG THE PERIPHERY OF A MID-LEVEL SUB-TROPICAL HIGH
  UNTIL FT72. THE SYSTEM WILL THEN MOVE WEST-NORTHWESTWARD ALONG THE
  PERIPHERY OF A MID-LEVEL SUB-TROPICAL HIGH UNTIL FT96. THE SYSTEM
  WILL THEN 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 FAIR
  BECAUSE ALL NWP MODELS ARE IN CLOSE AGREEMENT.
4.INTENSITY FORECAST
  THE SYSTEM WILL DEVELOP UNTIL FT72 DUE TO THE INFLUENCE OF
  INTERACTION WITH HIGH SSTS, HIGH TCHP, WEAK VWS AND GOOD
  UPPER-LEVEL OUTFLOW. THE SYSTEM WILL THEN WEAKEN UNTIL FT96 DUE TO
  THE INFLUENCE OF INTERACTION WITH HIGH SSTS AND LAND. THE SYSTEM
  WILL THEN WEAKEN RAPIDLY UNTIL FT120 DUE TO THE INFLUENCE OF LAND.
  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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