WTPQ31 RJTD 071200
RSMC TROPICAL CYCLONE PROGNOSTIC REASONING
REASONING NO.14 FOR TY 2522 HALONG (2522)
1.GENERAL COMMENTS
  TY HALONG IS LOCATED AT 28.1N, 137.2E. INFORMATION ON THE CURRENT
  POSITION IS BASED ON THE EYE IN ANIMATED MSI AND SURFACE
  OBSERVATIONS. POSITIONAL ACCURACY IS GOOD. CENTRAL PRESSURE IS
  950HPA AND MAXIMUM SUSTAINED WINDS NEAR THE CENTER ARE 90KNOTS.
  THE SYSTEM IS IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT UNDER THE
  INFLUENCE OF HIGH SSTS, HIGH TCHP 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 NORTHWESTWARD BETWEEN TWO MID-LEVEL
  SUB-TROPICAL HIGHS. ANIMATED MSI SHOWS THE EYE HAS BECOME
  DISTINCT. ANIMATED MSI SHOWS GOOD CLOUD CHARACTERISTICS OF
  ANTICYCLONIC OUTFLOW. WATER VAPOR IMAGERY SHOWS DRY AIR AROUND THE
  SYSTEM.
3.TRACK FORECAST
  THE SYSTEM WILL GRADUALLY TURN TO THE NORTH-NORTHEAST BETWEEN TWO
  MID-LEVEL SUB-TROPICAL HIGHS UNTIL FT24. THE SYSTEM WILL THEN
  GRADUALLY ACCELERATE AND MOVE EAST-NORTHEASTWARD UNDER THE
  INFLUENCE OF MID-LATITUDE PREVAILING WESTERLIES UNTIL FT96. THE
  TRACK FORECAST IS BASED ON GSM PREDICTIONS, AND REFERENCE TO OTHER
  NWP MODELS. TRACK FORECAST CONFIDENCE IS FAIR UNTIL FT24 BUT LOW
  THEREAFTER DUE TO SIGNIFICANT DIFFERENCES AMONG NWP MODEL OUTPUTS.
4.INTENSITY FORECAST
  THE SYSTEM WILL MAINTAIN ITS INTENSITY UNTIL FT24 DUE TO THE
  INFLUENCE OF INTERACTION WITH HIGH SSTS, HIGH TCHP, WEAK VWS AND
  DRY AIR. THE SYSTEM WILL THEN DEVELOP UNTIL FT36 DUE TO THE
  INFLUENCE OF INTERACTION WITH HIGH SSTS AND HIGH TCHP. THE SYSTEM
  WILL THEN WEAKEN UNTIL FT96 DUE TO THE INFLUENCE OF INTERACTION
  WITH LOWER SSTS, LOW TCHP AND STRONG VWS. THE SYSTEM WILL
  TRANSFORM INTO AN EXTRATROPICAL CYCLONE BY FT96. THE INTENSITY
  FORECAST IS BASED ON A CONSENSUS OF GUIDANCE DATA INCLUDING GSM.
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