WTPQ32 RJTD 011200
RSMC TROPICAL CYCLONE PROGNOSTIC REASONING
REASONING NO.35 FOR STS 2509 KROSA (2509)
1.GENERAL COMMENTS
  STS KROSA IS LOCATED AT 34.6N, 141.3E. INFORMATION ON THE CURRENT
  POSITION IS BASED ON ANIMATED MSI AND SURFACE OBSERVATIONS.
  POSITIONAL ACCURACY IS GOOD. CENTRAL PRESSURE IS 975HPA AND
  MAXIMUM SUSTAINED WINDS NEAR THE CENTER ARE 50KNOTS. THE SYSTEM IS
  IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT UNDER THE INFLUENCE OF
  HIGH SSTS, WEAK VWS AND DRY AIR. 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 NORTHWARD ALONG THE WESTERN 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-F18/SSMIS 89 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 FT03. THE SYSTEM WILL THEN MOVE SLOWLY
  NORTH-NORTHEASTWARD ALONG THE PERIPHERY OF A MID-LEVEL
  SUB-TROPICAL HIGH UNTIL FT12. THE SYSTEM WILL THEN GRADUALLY
  ACCELERATE AND MOVE EAST-NORTHEASTWARD ALONG THE PERIPHERY OF A
  MID-LEVEL SUB-TROPICAL HIGH UNTIL FT72. THE SYSTEM WILL THEN MOVE
  EASTWARD ALONG THE PERIPHERY OF A MID-LEVEL SUB-TROPICAL HIGH
  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 GRADUALLY DEVELOP UNTIL FT06 DUE TO THE INFLUENCE
  OF INTERACTION WITH HIGH SSTS, WEAK VWS AND DRY AIR. THE SYSTEM
  WILL THEN MAINTAIN ITS INTENSITY UNTIL FT24 DUE TO THE INFLUENCE
  OF INTERACTION WITH HIGH SSTS, WEAK VWS, REDUCED TCHP AND DRY AIR.
  THE SYSTEM WILL THEN WEAKEN UNTIL FT96 DUE TO THE INFLUENCE OF
  INTERACTION WITH LOWER SSTS AND LOW TCHP. 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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