WTPQ31 RJTD 191800
RSMC TROPICAL CYCLONE PROGNOSTIC REASONING
REASONING NO.12 FOR STS 2518 RAGASA (2518)
1.GENERAL COMMENTS
  STS RAGASA IS LOCATED AT 16.6N, 129.9E. INFORMATION ON THE CURRENT
  POSITION IS BASED ON ANIMATED MSI AND SURFACE OBSERVATIONS.
  POSITIONAL ACCURACY IS FAIR. CENTRAL PRESSURE IS 990HPA 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 WEST-NORTHWESTWARD ALONG THE SOUTHWESTERN
  PERIPHERY OF A MID-LEVEL SUB-TROPICAL HIGH. ANIMATED MSI SHOWS THE
  FORMATION OF A BAND WITH A CURVATURE SUGGESTING THE CSC. WATER
  VAPOR IMAGERY SHOWS DRY AIR AROUND THE SYSTEM. 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 SLOWLY NORTHWESTWARD DUE TO INTERACTION WITH
  AN UPPER VORTEX UNTIL FT24. THE SYSTEM WILL THEN MOVE WESTWARD
  ALONG THE PERIPHERY OF A MID-LEVEL SUB-TROPICAL HIGH UNTIL FT120.
  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 MAINTAIN ITS INTENSITY
  UNTIL FT96 DUE TO THE INFLUENCE OF INTERACTION WITH REDUCED TCHP
  AND LAND. THE SYSTEM WILL THEN WEAKEN UNTIL FT120 DUE TO THE
  INFLUENCE OF LAND. THE INTENSITY FORECAST IS BASED ON A CONSENSUS
  OF GUIDANCE DATA INCLUDING GSM.
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