9/3 – Rob Knight’s Tuesday Morning HURRICANE DORIAN Update

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Dorian continues to pound Grand Bahama Island early this morning while moving little.  The eye-wall has become a little less defined over the past few hours on radar.  On infrared satellite images, the eye remains fairly well defined, but the surrounding deep convection is somewhat fragmented.  Upper-level outflow is a bit restricted over the western semicircle of the circulation.  The initial intensity is held at 105 kt. Dorian is expected to more or less maintain its intensity for about 36 hours. After that time period, increasing vertical shear should cause gradual weakening. However, the system is likely to remain a major hurricane for the next few days.

Dorian has been nearly stationary for the past 18 hours, as steering currents in its vicinity have collapsed.  The global models indicate that a weakness in the subtropical ridge will develop in response to a trough that will amplify along the east coast of the United States within the next day or so.  Dorian should respond to these changes by beginning to move north-northwestward toward the weakness in the ridge a little later today.  The system should turn northward with a gradual increase in forward speed as it moves through the weakness in around 48 hours. Later in the period, the cyclone should accelerate northeastward on the southern side of the trough.  The official track forecast is similar to the previous one, and is fairly close to the model consensus.