[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT43 KNHC 060238
TCDAT3

Tropical Storm Lee Discussion Number   3
NWS National Hurricane Center Miami FL       AL132023
1100 PM AST Tue Sep 05 2023

The satellite structure of Lee has continued to improve tonight. A
prominent curved band of deep convection wraps around the western
and southern portions of the circulation. Recent SSMIS and GMI
microwave images reveal deep convection is occurring near the
center, though it is slightly displaced by some northeasterly shear.
There are also hints of a formative inner core trying to take shape,
all of which suggest that Lee is strengthening. The initial
intensity is raised to 45 kt for this advisory, in best agreement
with a T3.0 Dvorak classification from TAFB.

Lee continues to move west-northwestward at about 15 kt. A mid-level
ridge over the central subtropical Atlantic is expected to be the
primary steering mechanism for the next several days, with Lee
forecast to continue on a west-northwestward heading across the
central tropical Atlantic through the forecast period. Once again,
the track guidance is in fairly good agreement on this scenario.
Overall, the latest NHC track forecast is very similar to the
previous prediction, with only minor adjustments that keep our
forecast between the simple and corrected consensus aids. Users are
reminded that the average NHC forecast track errors are around 125
and 175 n mi on days 4 and 5, respectively. Thus, it is too soon to
determine exactly how close this system will be to the Leeward
Islands by the weekend.

The atmospheric and oceanic conditions appear extremely favorable
for rapid intensification (RI) during the next several days,
particularly once the northeasterly shear over Lee subsides in a day
or so. The forecast track of Lee brings the cyclone over anomalously
warm SSTs during the next several days, with generally low shear and
favorable upper diffluence to support significant strengthening. The
updated NHC intensity forecast has been adjusted slightly higher
than the previous one, toward the latest IVCN and HCCA aids. This
forecast calls for Lee to become a hurricane in 24 h and a major
hurricane by 60 h, with continued intensification thereafter. It is
noted that the regional hurricane models depict even stronger
solutions, so future adjustments could be necessary. Regardless,
Lee bears close monitoring as there is high confidence it will
become a very powerful hurricane by this weekend.


KEY MESSAGES:

1. Lee is forecast to become a major hurricane by late this week and
could bring impacts to the Leeward Islands this weekend. While it is
too soon to determine the location and magnitude of these possible
impacts, interests in this area should monitor the progress of Lee
and further updates to the forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  06/0300Z 13.5N  43.0W   45 KT  50 MPH
 12H  06/1200Z 14.1N  44.9W   55 KT  65 MPH
 24H  07/0000Z 14.9N  47.2W   65 KT  75 MPH
 36H  07/1200Z 15.7N  49.7W   75 KT  85 MPH
 48H  08/0000Z 16.6N  52.2W   90 KT 105 MPH
 60H  08/1200Z 17.8N  54.8W  105 KT 120 MPH
 72H  09/0000Z 18.9N  57.1W  115 KT 130 MPH
 96H  10/0000Z 20.8N  61.5W  125 KT 145 MPH
120H  11/0000Z 22.5N  65.0W  130 KT 150 MPH

$$
Forecaster Reinhart
This weather bulletin was brought to you by:
www.nashvilleweather.net