Earl affects the Canadian Maritimes; Ex-Gaston likely to regenerate; Watching the BOC

Tropical Update

Earl is now racing off towards the NE as a strong tropical storm. Satellite imagery suggests that the system has begun to make an extratropical transition with an expanding wind-field particularly to the south. Earl is expected to continue to race off towards the NE with a decrease in forward speed in 24-36 hours. By then, Earl should be fully extratorpical as it is absorbed by a larger and more powerful extratropical low pressure area. Nonetheless, interests along eastern Canada and points northward should monitor the progress of Earl.


Figure 1. Satellite image of Hurricane Earl taken from the International Space Station. The image was taken on September 2, 2010.

The remnants of Gaston continue to slowly become better organized. The system does currently lack a large amount of organized deep convection, plus the surface circulation is exposed, however, satellite imagery reveals that the system has been firing intense cloud tops mainly in the western quadrant. Environmental conditions do appear relatively conducive for re-development into a tropical depression with the largest impediment on organization being dry air. I expect slow organization and intensification of Earl over the next few days due to the relatively dry and stable air that surrounds it. Once it does enter into the Caribbean or southwestern Atlantic a faster rate of intensification should be expected since conditions in those regions are favorable.
Ex-Gaston currently continues to move towards the west at around 10mph. This motion should continue through the forecast period (the next 3 days) with a possible turn more towards the WNW as it is steered by the subtropical ridge to the north. Although the system currently is weak, intensification is forecasted, so interests along the Lesser and Greater Antilles should closely monitor the progress of ex-Gaston. Currently I give this area a 90% chance of re-developing into a tropical depression.

An area of moderate to strong showers and thunderstorms accompanied by a surface trough continues to show slow signs of organization. Environmental conditions do appear conducive for further organization of this feature with an anticyclone place atop the convective cluster. Several global models have been hinting at the possibility of cyclogenesis in this area for the past few days. This feature should continue to move off towards the NW and due to weak steering currents, it should have enough time over water to develop. Currently I agree with the reasoning behind the NHC on the percentage given for a tropical cyclone to form...30%.

A tropical wave accompanied by an elongated area of low pressure located near the Cape Verde islands has been showing no signs of organization. Environmental conditions are currently marginally conducive for further development of this area as it moves generally towards the NW. Due to this, I agree with the NHC...I currently believe that there is a 10% chance that this will develop into a tropical cyclone during the next 48 hours.

Elsewhere tropical nor subtropical development is anticipated through Sunday.


Figure 2. Visible satellite image of the tropical Atlantic.

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