WTPQ31 RJTD 061200
RSMC TROPICAL CYCLONE PROGNOSTIC REASONING
REASONING NO.10 FOR STS 2522 HALONG (2522)
1.GENERAL COMMENTS
  STS HALONG IS LOCATED AT 26.1N, 140.1E. INFORMATION ON THE CURRENT
  POSITION IS BASED ON ANIMATED MSI AND SURFACE OBSERVATIONS.
  POSITIONAL ACCURACY IS GOOD. CENTRAL PRESSURE IS 985HPA AND
  MAXIMUM SUSTAINED WINDS NEAR THE CENTER ARE 60KNOTS. THE SYSTEM IS
  IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT UNDER THE INFLUENCE OF
  HIGH SSTS, HIGH TCHP AND WEAK VWS. HOWEVER, ITS TEMPORAL
  SUSPENSION OF DEVELOPMENT HAS CAUSED IT 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 BETWEEN TWO MID-LEVEL
  SUB-TROPICAL HIGHS. 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. GPM/GMI 89 GHZ MICROWAVE IMAGERY SHOWS
  THE SYSTEM HAS A BAND WITH CURVATURE INDICATING THE CSC.
3.TRACK FORECAST
  THE SYSTEM WILL GRADUALLY TURN TO THE NORTH BETWEEN TWO MID-LEVEL
  SUB-TROPICAL HIGHS UNTIL FT48. THE SYSTEM WILL THEN GRADUALLY
  ACCELERATE AND MOVE EAST-NORTHEASTWARD UNDER THE INFLUENCE OF
  MID-LATITUDE PREVAILING WESTERLIES 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 RAPIDLY UNTIL FT24 DUE TO THE INFLUENCE OF
  INTERACTION WITH HIGH SSTS, HIGH TCHP AND WEAK VWS. THE SYSTEM
  WILL THEN GRADUALLY DEVELOP UNTIL FT48 DUE TO THE INFLUENCE OF
  INTERACTION WITH HIGH SSTS, HIGH TCHP AND WEAK VWS. THE SYSTEM
  WILL THEN GRADUALLY DEVELOP UNTIL FT72 DUE TO THE INFLUENCE OF
  GOOD UPPER-LEVEL OUTFLOW. THE SYSTEM WILL THEN WEAKEN UNTIL FT120
  DUE TO THE INFLUENCE OF INTERACTION WITH LOW SSTS, LOW TCHP AND
  STRONG VWS. 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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