WTPQ31 RJTD 120000
RSMC TROPICAL CYCLONE PROGNOSTIC REASONING
REASONING NO. 7 FOR TS 2406 SON-TINH (2406)
1.GENERAL COMMENTS
  TS SON-TINH IS LOCATED AT 31.3N, 153.1E. INFORMATION ON THE
  CURRENT POSITION IS BASED ON ANIMATED MSI AND SURFACE
  OBSERVATIONS. POSITIONAL ACCURACY IS FAIR. CENTRAL PRESSURE IS
  998HPA AND MAXIMUM SUSTAINED WINDS NEAR THE CENTER ARE 35KNOTS.
  THE SYSTEM IS IN A NEUTRAL ENVIRONMENT FOR DEVELOPMENT UNDER THE
  INFLUENCE OF WEAK VWS AND LOW TCHP. THIS HAS CAUSED THE SYSTEM 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 NORTHWESTWARD ALONG THE SOUTHWESTERN
  PERIPHERY OF A MID-LEVEL SUB-TROPICAL HIGH. ANIMATED MSI SHOWS THE
  SEPARATION OF ACTIVE CONVECTIVE CLOUD CLUSTERS FROM THE CSC. WATER
  VAPOR IMAGERY SHOWS DRY AIR AROUND THE SYSTEM. DMSP-F18/SSMIS 89
  GHZ MICROWAVE IMAGERY SHOWS THE SYSTEM HAS ACTIVE CONVECTIVE CLOUD
  CLUSTERS AROUND THE CSC.
3.TRACK FORECAST
  THE SYSTEM WILL MOVE NORTHWESTWARD ALONG THE PERIPHERY OF A
  MID-LEVEL SUB-TROPICAL HIGH UNTIL FT24. THE SYSTEM WILL THEN MOVE
  NORTH-NORTHWESTWARD ALONG THE PERIPHERY OF A MID-LEVEL
  SUB-TROPICAL HIGH UNTIL FT48. 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 MAINTAIN ITS INTENSITY UNTIL FT24 DUE TO THE
  INFLUENCE OF INTERACTION WITH WEAK VWS AND LOW TCHP. THE SYSTEM
  WILL THEN WEAKEN UNTIL FT48 DUE TO THE INFLUENCE OF INTERACTION
  WITH LOWER SSTS, REDUCED TCHP AND DRY AIR. THE SYSTEM WILL WEAKEN
  TO TD INTENSITY BY FT48. THE INTENSITY FORECAST IS BASED ON A
  CONSENSUS OF GUIDANCE DATA INCLUDING GSM.
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