WTPQ32 RJTD 131800
RSMC TROPICAL CYCLONE PROGNOSTIC REASONING
REASONING NO. 8 FOR STS 2407 AMPIL (2407)
1.GENERAL COMMENTS
  STS AMPIL IS LOCATED AT 25.5N, 139.4E. INFORMATION ON THE CURRENT
  POSITION IS BASED ON ANIMATED MSI AND SURFACE OBSERVATIONS.
  POSITIONAL ACCURACY IS FAIR. CENTRAL PRESSURE IS 975HPA AND
  MAXIMUM SUSTAINED WINDS NEAR THE CENTER ARE 60KNOTS. THE SYSTEM IS
  IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT UNDER THE INFLUENCE OF
  HIGH SSTS AND WEAK VWS. 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 NORTHEASTWARD UNDER THE INFLUENCE OF
  LOW-LEVEL FLOW. ANIMATED MSI SHOWS THE SYSTEM HAS A BAND WITH A
  CURVATURE SUGGESTING THE CSC. WATER VAPOR IMAGERY SHOWS DRY AIR
  AROUND THE SYSTEM. NOAA-20/ATMS 85 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
  NORTH-NORTHEASTWARD ALONG THE PERIPHERY OF A MID-LEVEL
  SUB-TROPICAL HIGH UNTIL FT72. THE SYSTEM WILL THEN GRADUALLY
  ACCELERATE AND MOVE EAST-NORTHEASTWARD UNDER THE INFLUENCE OF A
  MID-LATITUDE TROUGH UNTIL FT120. THE TRACK FORECAST IS BASED ON
  GSM PREDICTIONS, AND REFERENCE TO OTHER NWP MODELS. TRACK FORECAST
  CONFIDENCE IS FAIR UNTIL FT72 BUT LOW THEREAFTER DUE TO
  SIGNIFICANT DIFFERENCES AMONG NWP MODEL OUTPUTS.
4.INTENSITY FORECAST
  THE SYSTEM WILL DEVELOP UNTIL FT60 DUE TO THE INFLUENCE OF
  INTERACTION WITH HIGH TCHP AND WEAK VWS. THE SYSTEM WILL THEN
  MAINTAIN ITS INTENSITY UNTIL FT72 DUE TO THE INFLUENCE OF
  INTERACTION WITH LOWER SSTS AND GOOD UPPER-LEVEL OUTFLOW. THE
  SYSTEM WILL THEN WEAKEN UNTIL FT96 DUE TO THE INFLUENCE OF
  INTERACTION WITH LOWER SSTS AND REDUCED TCHP. THE SYSTEM WILL THEN
  GRADUALLY WEAKEN UNTIL FT120 IN A STATE OF EXTRATROPICAL
  TRANSITION. 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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