Hanna made landfall, TD10 came and went, but is making a comeback.

Tropical Storm Hanna made landfall on the MS/AL border at 14Z on 9/14
with about 40kt winds and disorganized rain (not an eyewall or
well-formed spiral bands).  The only serious effect besides some minor
localized flooding was a wind damage report from Mobile County, AL where
"several trees were blown down".

TD10 formed at 21Z on 9/14 just a few miles off the eastern Venezuela
coast (very low latitude), tracked WNW along the coast and dissipated
back to an open wave on the 15th at 21Z.  However, it is still a key
feature in the Caribbean, presently located at about 17N 73W (just south
of Hispaniola) and moving WNW at 20kts.  Conditions are now marginal for
development, but will be improving, so re-development is possible, or
even likely.  It's still got a lot of centralized relative vorticity
(curvature of the wind field), moderate upper-level divergence (decent
outflow), and healthy convection.  As evident in the satellite imagery,
there is westerly shear, caused by an upper-level anticyclone to its
south.  

The computer models are largely in agreement on strengthening it, and
also that Cuba and then Florida will be the target areas.  Some keep it
fairly weak, while some have it reaching CAT3 status by landfall (for
those of you who check the models closely, the 06Z run of GFDL was
fascinating, ask for details if interested).  Should this reform and
reach TS strength, the next name on deck is Isidore.  Just FYI, the last
time we had Isidore was in late September 1996, and she reached CAT3
intensity in the central Atlantic.  The time before that was early-mid
September 1990, and she reached CAT2 intensity, also tracking northward
across the central Atlantic. 

Please visit my tropical Atlantic headquarters.

Gustav becomes extratropical, Hanna forms, central and eastern Atlantic still interesting.

Following the forecast remarkably well, Gustav continued on his rapid
northeasterly course on Wednesday afternoon and Thursday, making
landfall on extreme eastern Nova Scotia then southwest Newfoundland as a
weak CAT 1 hurricane early Thursday morning.  He transitioned to
extratropical and was absorbed into the mid-latitude trough just hours
after the landfalls.

TD9 formed late Wednesday night from that large area of disturbed
weather in the central Gulf that I had been mentioning for a few days. 
Despite poor convective patterns, pressures had dropped persistently,
reaching 1001mb by the time it was classified as a TD (very low for that
point in its lifetime!).  At 09Z today, aircraft recon, buoys, and
nearby ships reported that the sustained winds were strong enough to
upgrade it to TS Hanna, the 8th named storm of the season.  The 12Z
advisory places Hanna at 27.0N 88.6W and tracking NW at 7kts (after
having been meandering for a while).  Intensity is observed to be 40kts
and 1002mb.  A Tropical Storm Watch is in effect for the eastern half of
the Florida peninsula, and a Tropical Storm Warning is in effect from
the central FL panhandle over to near New Orleans, LA... see
http://www.nhc.noaa.gov/ftp/graphics/AT09/AL0902W.GIF for details.  

Currently, the convection is all southeast of the low-level center (due
to 10-15kt NW vertical shear), which has been exposed during much of
Hanna's existence.  The forecast is for further strengthening, and for
accelerated motion.  As the intensity picks up to 50kts, the track
should bend more northerly, and the NHC forecast is for landfall near
the FL/AL border (although many computer models predict landfall a bit
further west, like Gulfport) Saturday around noon local time. 

The tropical wave that I positioned at 19N 31W in the 9/11 update is now
at about 14N 52W (at least that's where the convection is occuring now,
the wave itself is much larger and harder to pin down) and becoming
better organized as it clears the high-shear zone.  It's tracking W at
20kts and has the potential to become TD10 during the weekend.

Lastly, there's a tropical wave just exiting the African coast with
fairly high, concentrated vorticity that is only in moderate shear. 
Though it lacks deep convection now, it will be closely watched the next
few days.

Please visit my tropical Atlantic headquarters.

Gustav becomes first hurricane of the season.

After coming within 20 miles of Cape Hatteras on Tuesday at 21Z as a
strong 984mb Tropical Storm, he has since begun to rapidly move away
from the coast.  And, as anticipated, the baroclinic assist he's getting
has allowed him to intensify to a hurricane, the first of the season. 
At 15Z, he was located at 38.6N 69.7W and tracking NE at 20kts.  Maximum
sustained winds are 65kts and the MSLP is 975mb.  The forecast is for
continued acceleration to the NE, slamming into Nova Scotia and
Newfoundland on Thursday, with little change in strength, until 2-3 days
out when he turns extratropical and is absorbed by the trough.  As if to
mimic the October 1991 "Perfect Storm" scenario on a weaker scale, the
NHC states that "SURFACE OBSERVATIONS INDICATE THAT BAROCLINIC
CYCLOGENESIS IS OCCURRING OVER THE NEW ENGLAND STATES AND THE CANADIAN
MARITIMES.  GUSTAV IS FORECAST TO MERGE WITH THIS DEVELOPING
NON-TROPICAL LOW AND BECOME A LARGE AND POWERFUL EXTRATROPICAL STORM AS
IT CROSSES NOVA SCOTIA AND NEWFOUNDLAND".  By the way, the last time we
had to wait until Sept 11 for a hurricane was 1941, so yes, the season
is behind schedule.

The area of disturbed weather in the Gulf that I mentioned yesterday is
becoming better organized.  It has a broad area of vorticity and a Low
associated with it.  This is biggest area of concern in the Atlantic now
for the US, as anything that develops in the Gulf is guaranteed to make
landfall somewhere.

The tropical wave that has been marching across the Atlantic since last
week is now at 18N 52W and tracking W at 10kts.  Conditions remain
unfavorable for development.

A tropical wave at 19N 31W now has a 1011mb Low with it, along with a
nice low-level circulation and some moderate convection.  

Besides the obvious significance of this day, I recalled that this same
day last year had Hurricane Erin sitting not far off the northeast US
coast.  Today, at the same time and nearly same place, Hurricane Gustav
is there.  See the attached image for a comparison.  Although the
visible appearance differs slightly, the central pressures of the two
storms are nearly identical.  Just a strange coincidence I thought I'd
bring to your attention.

Please visit my tropical Atlantic headquarters.