• Pacific-NW: Dolphin R8

    From Weather Alert@21:1/175 to All on Tue Sep 22 23:28:00 2020
    WTPQ30 RJTD 221800
    RSMC TROPICAL CYCLONE PROGNOSTIC REASONING
    REASONING NO. 8 FOR STS 2012 DOLPHIN (2012)
    1.GENERAL COMMENTS
    STS DOLPHIN IS LOCATED AT 30.1N, 136.4E. INFORMATION ON THE
    CURRENT POSITION IS BASED ON ANIMATED MSI AND SURFACE
    OBSERVATIONS. POSITIONAL ACCURACY IS FAIR. CENTRAL PRESSURE IS
    975HPA AND MAXIMUM SUSTAINED WINDS NEAR THE CENTER ARE 60KNOTS.
    THE SYSTEM IS IN A NEUTRAL ENVIRONMENT FOR DEVELOPMENT UNDER THE
    INFLUENCE OF HIGH SSTS, HIGH TCHP, INCREASED VWS AND DRY AIR. 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 NORTH-NORTHEASTWARD BETWEEN TWO MID-LEVEL
    SUB-TROPICAL HIGHS. ANIMATED MSI SHOWS THE SYSTEM HAS A BAND WITH
    A CURVATURE SUGGESTING THE CSC. 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 MOVE NORTHEASTWARD ALONG THE PERIPHERY OF A
    MID-LEVEL SUB-TROPICAL HIGH UNTIL FT48. THE SYSTEM WILL THEN MOVE
    NORTH-NORTHEASTWARD UNDER THE INFLUENCE OF A MID-LATITUDE TROUGH
    UNTIL FT72. THE TRACK FORECAST IS BASED ON GSM PREDICTIONS, AND
    REFERENCE TO OTHER NWP MODELS. TRACK FORECAST CONFIDENCE IS FAIR
    BECAUSE ALL NWP MODELS ARE IN CLOSE AGREEMENT.
    4.INTENSITY FORECAST
    THE SYSTEM WILL WEAKEN UNTIL FT48 DUE TO THE INFLUENCE OF
    INTERACTION WITH LOWER SSTS, REDUCED TCHP, INCREASED VWS AND DRY
    AIR. THE SYSTEM WILL THEN MAINTAIN ITS INTENSITY UNTIL FT72 IN A
    STATE OF EXTRATROPICAL TRANSITION. THE SYSTEM WILL TRANSFORM INTO
    AN EXTRATROPICAL CYCLONE BY FT72. THE INTENSITY FORECAST IS BASED
    ON GUIDANCE DATA.
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