WTPQ32 RJTD 170000
RSMC TROPICAL CYCLONE PROGNOSTIC REASONING
REASONING NO.21 FOR TY 2407 AMPIL (2407)
1.GENERAL COMMENTS
  TY AMPIL IS LOCATED AT 36.5N, 143.9E. INFORMATION ON THE CURRENT
  POSITION IS BASED ON ANIMATED MSI AND SURFACE OBSERVATIONS.
  POSITIONAL ACCURACY IS GOOD. CENTRAL PRESSURE IS 950HPA AND
  MAXIMUM SUSTAINED WINDS NEAR THE CENTER ARE 85KNOTS. THE SYSTEM IS
  IN A NEUTRAL ENVIRONMENT FOR DEVELOPMENT UNDER THE INFLUENCE OF
  HIGH SSTS AND REDUCED 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 EAST-NORTHEASTWARD ALONG THE NORTHWESTERN
  PERIPHERY OF A MID-LEVEL SUB-TROPICAL HIGH. ANIMATED MSI SHOWS THE
  SHORTENING OF A BAND WITH CURVATURE SUGGESTING THE CSC. ANIMATED
  MSI SHOWS GOOD CLOUD CHARACTERISTICS OF ANTICYCLONIC OUTFLOW.
  WATER VAPOR IMAGERY SHOWS DRY AIR AROUND THE SYSTEM.
  DMSP-F17/SSMIS 89 GHZ MICROWAVE IMAGERY SHOWS THE SYSTEM HAS A
  BAND WITH CURVATURE INDICATING THE CSC.
3.TRACK FORECAST
  THE SYSTEM WILL GRADUALLY ACCELERATE AND MOVE EAST-NORTHEASTWARD
  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 GRADUALLY WEAKEN UNTIL FT12 DUE TO THE INFLUENCE
  OF LOWER SSTS. THE SYSTEM WILL THEN WEAKEN UNTIL FT24 DUE TO THE
  INFLUENCE OF INTERACTION WITH LOWER SSTS, REDUCED TCHP AND
  INCREASED VWS. THE SYSTEM WILL THEN GRADUALLY WEAKEN UNTIL FT48 IN
  A STATE OF EXTRATROPICAL TRANSITION. THE SYSTEM WILL TRANSFORM
  INTO AN EXTRATROPICAL CYCLONE BY FT48. THE INTENSITY FORECAST IS
  BASED ON A CONSENSUS OF GUIDANCE DATA INCLUDING GSM.
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