21 September 2002

Isidore becomes first major hurricane, Kyle forms in central Atlantic, east Atlantic becomes active.

Hurricane Isidore was upgraded to a CAT3 storm today at 15Z, making him
the first major hurricane of the season.  He made landfall on western
Cuba yesterday (with devastating rains exceeding 2' at places), and is
now entering the southeastern Gulf.  Shear is almost zero, and the SSTs
are actually an interesting story (as relayed by the Air Force C-130
crew): Although he's moving slowly and the Gulf waters are much
shallower than the Caribbean, cold upwelling is not a concern because of
the loop current... an ocean current that runs between Cuba and Yucatan,
through the Gulf, then exits between Florida and Cuba. Very warm (30C)
SSTs are constantly being replenished so this may be a setup for rapid
intensification today.

The satellite imagery now reveals a mature storm, not only at microwave
frequencies, but also at VIS and IR.  The eye will fully develop today
and the intimidation factor goes up with that, knowing that he will make
landfall somewhere along the Gulf coast.

At 15Z, Hurricane Isidore was located at 21.9N 86.1W and tracking W at
6kts.  The maximum sustained winds have reached 100kts and the MSLP is
down to 955mb, as observed by aircraft recon.  A Tropical Storm Warning
is still in effect for extreme western Cuba and the Isle of Youth, and a
Hurricane Warning is in effect for northern and eastern Yucatan
Peninsula.  The forecast is for a continued westward heading through
Tuesday, with winds of 125kts (strong CAT4).  It's still VERY difficult
to say what's in store for him after Tuesday; the trough off the US West
coast now could be a big player in either leaving him behind again to
linger in the Gulf or to pick him up and steer the storm more
northward.  It's simply too early to tell.

At 21Z yesterday, the broad circulation I mentioned ESE of Bermuda was
upgraded to Subtropical Depression 12, then at 09Z today, it was
upgraded again to Subtropical Storm Kyle, the 11th named storm of the
season.  It should be switch over Tropical Storm today, as it's
continually taking on more and more tropical characteristics (mature
warm core, banding, anticyclone aloft, CDO, etc).  At 15Z today, STS
Kyle was located at 31.3N 51.6W and heading N at 6kts.  Current intesity
based on satellite estimates is 40kts and 1007mb.  Given the relatively
light shear and moderate SSTs in his environment, further
intensification is likely, and the offical NHC forecast brings him to
hurricane status by Tuesday morning.  Also, he's in very weak steering
flow, so the current position may well be close to the position on

There's a very healthy tropical wave at 12N 44W (about 1750km east of
the Windward Islands) and tracking W at 12kts.  It has a 1010mb Low
associated with it, has been getting better organized, and conditions
are favorable for further development.  It could become TD13 in the near
future (and the next name on deck is Lili).

Yet another interesting wave near the Cape Verde Islands is at 10N 24W
and tracking W at 13kts.  It also has a 1010mb Low with it, but
convection is not as vigorous as with the first wave, so if anything
would be slower to develop (if it does at all).

Please visit my tropical Atlantic headquarters.

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