WTPQ32 RJTD 141800
RSMC TROPICAL CYCLONE PROGNOSTIC REASONING
REASONING NO.12 FOR STS 2407 AMPIL (2407)
1.GENERAL COMMENTS
  STS AMPIL IS LOCATED AT 28.5N, 141.3E. INFORMATION ON THE CURRENT
  POSITION IS BASED ON ANIMATED MSI AND SURFACE OBSERVATIONS.
  POSITIONAL ACCURACY IS GOOD. CENTRAL PRESSURE IS 975HPA AND
  MAXIMUM SUSTAINED WINDS NEAR THE CENTER ARE 60KNOTS. THE SYSTEM IS
  IN A NEUTRAL ENVIRONMENT FOR DEVELOPMENT UNDER THE INFLUENCE OF
  HIGH SSTS, WEAK VWS, REDUCED TCHP AND DRY AIR. 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 NORTHWARD ALONG THE WESTERN PERIPHERY OF A
  MID-LEVEL SUB-TROPICAL HIGH. ANIMATED MSI SHOWS THE SYSTEM HAS 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 NORTHWARD ALONG THE PERIPHERY OF A MID-LEVEL
  SUB-TROPICAL HIGH UNTIL FT48. THE SYSTEM WILL THEN MOVE
  EAST-NORTHEASTWARD 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 FT24 DUE TO THE INFLUENCE OF
  INTERACTION WITH HIGH SSTS AND WEAK VWS. THE SYSTEM WILL THEN
  MAINTAIN ITS INTENSITY UNTIL FT48 DUE TO THE INFLUENCE OF
  INTERACTION WITH HIGH SSTS, WEAK VWS, LAND AND REDUCED TCHP. THE
  SYSTEM WILL THEN WEAKEN UNTIL FT120 DUE TO THE INFLUENCE OF
  INTERACTION WITH LOWER SSTS AND INCREASED VWS. THE SYSTEM WILL
  TRANSFORM INTO AN EXTRATROPICAL CYCLONE BY FT120. THE INTENSITY
  FORECAST IS BASED ON A CONSENSUS OF GUIDANCE DATA INCLUDING GSM.
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