28 August 2002

Tropical wave near Cape Verde Islands attracts some interest.

For perhaps the first time this year, one of the many tropical waves to
exit the African coast has held its own as it traverses the open waters
of the tropical eastern Atlantic.  The wave in question is currently at
about 9N 27W and tracking W at 10kts.  Healthy signs include an obvious
low-level circulation (featuring a 1009mb Low), and convection that
continues to intensify.  The CDO has become larger and colder over the
past few hours, now with coldest tops at -80C.  Although the CDO is
slightly displaced to the SE from the low-level center, the difference
is not great, and so I suspect either the convection will shift to meet
the center or the center will shift to meet the convection.  VIS and IR
imagery both reveal organization, and although the last pass of a
high-res microwave instrument did not show much structure, the next pass
is at about 1200 MDT, and might show us a clearer picture of what's
going on under the developing CDO.

The SST there is about 28C, and that will change little (perhaps
decrease by a degree) in the next few days, before steadily increasing
once it makes it to 50W.  The vertical shear is also favorable, easterly
at 10kts now, and expected to decrease.  Lastly, it's entering the
climatologically favored time for "Cape Verde storms" to form, and there
seems to be something to be said for that.

If this system does continue to organize and become a named storm, it
would be the first purely tropical system of the year (the previous
three have been baroclinically initiated or enhanced).  The next
numbers/names on deck are TD4 then Dolly.

Models do not yet agree on a solution... one extreme is completely
dissolving the system within 5 days, while the other extreme intensifies
it and moves it WNW toward the Greater Antilles in 5 days.  Too early to
tell for sure, but the 500mb heights indicate to me that the westerly
course will persist for at least 2-3 days.
Please visit my tropical Atlantic headquarters.

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