09 July 2008

Bertha on a comeback...

After the encounter with higher shear and drier air yesterday, Bertha is back to a more symmetric shape with an open eye.  A microwave image (from SSM/I) at 0939Z this morning captured the eye reforming prior to it opening up in VIS and IR imagery.  Another microwave-instrument-bearing satellite had an overpass at 0521Z and there was not an eye at that time.  As of 15Z today, the intensity was estimated at 65kts and 987mb, a minimal CAT1 hurricane.  However, since then, the presentation has improved noticeably, and I suspect that at the 21Z advisory, we'll see something more like 75kts, with a strengthening trend in the forecast.

The SST is presently 27.5C under the storm, and will hover around that temperature for the coming days.  Vertical shear is southwesterly at ~15kts, which is moderate, but low enough to allow an eye to reform.

An interesting question remains... what about Bermuda?  In 4-5 days (weekend-ish), it appears that Bertha will have a close encounter with the island.  Just how close depends on the encroaching mid-latitude trough.  It could be responsible for not only steering/recurving Bertha away from the island, but also shearing and weakening it beforehand.  It will be a close call.

Elsewhere in the basin, there are easterly waves trekking across the deep tropics at about 50W, 35W, and 20W, none of which currently show signs of organization.

Please visit my tropical Atlantic headquarters.

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