WTPQ33 RJTD 150000
RSMC TROPICAL CYCLONE PROGNOSTIC REASONING
REASONING NO.21 FOR STS 2425 USAGI (2425)
1.GENERAL COMMENTS
  STS USAGI IS LOCATED AT 20.0N, 120.3E. INFORMATION ON THE CURRENT
  POSITION IS BASED ON ANIMATED MSI AND SURFACE OBSERVATIONS.
  POSITIONAL ACCURACY IS FAIR. CENTRAL PRESSURE IS 985HPA AND
  MAXIMUM SUSTAINED WINDS NEAR THE CENTER ARE 60KNOTS. THE SYSTEM IS
  IN A NEUTRAL ENVIRONMENT FOR DEVELOPMENT UNDER THE INFLUENCE OF
  REDUCED TCHP AND GOOD UPPER-LEVEL OUTFLOW. 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
  SYSTEM HAS A BAND WITH A 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 MOVE NORTH-NORTHWESTWARD ALONG THE PERIPHERY OF A
  MID-LEVEL SUB-TROPICAL HIGH UNTIL FT12. THE SYSTEM WILL THEN MOVE
  NORTHEASTWARD ALONG THE PERIPHERY OF A MID-LEVEL SUB-TROPICAL HIGH
  UNTIL FT24. THE SYSTEM WILL THEN REMAIN ALMOST STATIONARY DUE TO
  WEAK STEERING FLOW UNTIL FT72. THE TRACK FORECAST IS BASED ON GSM
  PREDICTIONS, AND REFERENCE TO OTHER NWP MODELS. TRACK FORECAST
  CONFIDENCE IS FAIR UNTIL FT12 BUT LOW THEREAFTER DUE TO
  SIGNIFICANT DIFFERENCES AMONG NWP MODEL OUTPUTS.
4.INTENSITY FORECAST
  THE SYSTEM WILL WEAKEN UNTIL FT72 DUE TO THE INFLUENCE OF
  INTERACTION WITH LOW TCHP AND LAND. THE SYSTEM WILL WEAKEN TO TD
  INTENSITY BY FT72. THE INTENSITY FORECAST IS BASED ON A CONSENSUS
  OF GUIDANCE DATA INCLUDING GSM.
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