WTPQ31 RJTD 051800
RSMC TROPICAL CYCLONE PROGNOSTIC REASONING
REASONING NO. 8 FOR STS 2504 DANAS (2504)
1.GENERAL COMMENTS
  STS DANAS IS LOCATED AT 21.1N, 117.8E. 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 50KNOTS. THE SYSTEM IS
  IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT UNDER THE INFLUENCE OF
  HIGH SSTS, HIGH TCHP, WEAK VWS AND GOOD UPPER-LEVEL OUTFLOW. 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 NORTH-NORTHEASTWARD ALONG THE
  NORTHWESTERN PERIPHERY OF A MID-LEVEL SUB-TROPICAL HIGH. ANIMATED
  MSI SHOWS THE FORMATION OF A BAND WITH A CURVATURE SUGGESTING THE
  CSC. ANIMATED MSI SHOWS GOOD CLOUD CHARACTERISTICS OF ANTICYCLONIC
  OUTFLOW. WATER VAPOR IMAGERY SHOWS DRY AIR IN THE DIRECTION OF THE
  MOVEMENT. METOP-B/MHS 85 GHZ MICROWAVE IMAGERY SHOWS THE SYSTEM
  HAS ACTIVE CONVECTIVE CLOUD CLUSTERS AROUND THE CSC.
3.TRACK FORECAST
  THE SYSTEM WILL MOVE NORTH-NORTHEASTWARD ALONG THE PERIPHERY OF A
  MID-LEVEL SUB-TROPICAL HIGH UNTIL FT48. THE SYSTEM WILL THEN TURN
  SHARPLY TO THE WEST UNTIL FT72. THE SYSTEM WILL THEN MOVE
  WEST-SOUTHWESTWARD UNTIL FT96. THE TRACK FORECAST IS BASED ON GSM
  PREDICTIONS, AND REFERENCE TO OTHER NWP MODELS. TRACK FORECAST
  CONFIDENCE IS LOW DUE TO SIGNIFICANT DIFFERENCES AMONG NWP MODEL
  OUTPUTS.
4.INTENSITY FORECAST
  THE SYSTEM WILL DEVELOP UNTIL FT36 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 AND REDUCED TCHP. THE SYSTEM
  WILL THEN WEAKEN RAPIDLY UNTIL FT96 DUE TO THE INFLUENCE OF
  INTERACTION WITH REDUCED TCHP AND LAND. THE SYSTEM WILL WEAKEN TO
  TD INTENSITY BY FT96. THE INTENSITY FORECAST IS BASED ON A
  CONSENSUS OF GUIDANCE DATA INCLUDING GSM.
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