[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 262102 CCA
TCDAT4

Hurricane Ian Discussion Number  15...Corrected
NWS National Hurricane Center Miami FL       AL092022
500 PM EDT Mon Sep 26 2022

Corrected header

Ian continues to strengthen over the northwestern Caribbean Sea. The
last report from the Air Force Hurricane Hunters around 1630 UTC
found 700-mb flight-level winds of 79 kt. The inner core appears
better organized, and the eyewall structure has greatly improved in
radar imagery from the Cayman Islands. The 18 UTC satellite
classifications from SAB and TAFB were a consensus T4.5/77 kt, but
the continued improvement in satellite structure warrants raising
the initial intensity to 85 kt for this advisory.

Atmospheric and oceanic conditions remain very favorable for
additional intensification during the next 24 h or so, as Ian moves
over the very warm waters of the northwestern Caribbean Sea and the
southeastern Gulf of Mexico while the shear remains quite low. The
NHC intensity forecast calls for Ian to become a major hurricane
before it reaches western Cuba early Tuesday. It is then forecast to
reach its peak intensity over the southeastern Gulf of Mexico in 36
h. After that, southwesterly shear in association with a deep-layer
trough over the eastern U.S. is forecast to significantly increase
over the hurricane on Wednesday and Thursday, which will likely
disrupt the vertical structure and import drier air into its
circulation. Despite these less favorable conditions, Ian is still
forecast to remain at or near major hurricane strength as it passes
near the west-central coast of Florida on Wednesday and Thursday.
The NHC intensity forecast agrees well with the latest IVCN and HCCA
aids.

Ian has made an expected turn toward the north-northwest, and its
initial motion is 330/11 kt. The hurricane will move
north-northwestward to northward over the next day or so as it is
steered by a mid-level ridge to the east. A turn to the
north-northeast with a decrease in forward speed is forecast on
Wednesday and Thursday as the center of Ian moves near the west
coast of Florida. The slower forward motion is likely to prolong the
storm surge, wind, and rainfall impacts, especially along the west
coast of Florida. The latest track guidance has come into better
agreement on this scenario, although it is noted that small
deviations to the shore-parallel track could have large implications
on the impacts at particular locations along the west coast of
Florida. The NHC track forecast has again been adjusted slightly
eastward at 48-72 h, which follows the latest trends in the global
model guidance and lies near but just west of the multi-model
consensus aids.

Based on the latest forecast and timing of expected impacts,
Hurricane and Storm Surge Warnings have been issued along the west
coast of Florida.


Key Messages:

1. Life-threatening storm surge, hurricane-force winds, flash
floods and possible mudslides are expected in portions of western
Cuba beginning this evening and continuing into Tuesday.
Devastating wind damage is possible where the core of Ian moves
across western Cuba. Efforts to protect life and property should be
rushed to completion.

2. There is the danger of life-threatening storm surge along much
of the Florida west coast where a storm surge warning has been
issued, with the highest risk from Fort Myers to the Tampa Bay
region.  Residents in these areas should listen to advice given by
local officials.

3. Hurricane-force winds are expected in the hurricane warning area
in west-central Florida beginning Wednesday morning with tropical
storm conditions expected by late Tuesday.

4. Heavy rainfall will increase across the Florida Keys and south
Florida Tuesday, spreading to central and northern Florida Wednesday
and Thursday, potentially causing flash, urban and small stream
flooding. Significant prolonged river flooding is likely across
central Florida.



FORECAST POSITIONS AND MAX WINDS

INIT  26/2100Z 20.3N  83.2W   85 KT 100 MPH
 12H  27/0600Z 21.7N  83.8W  105 KT 120 MPH
 24H  27/1800Z 23.6N  84.0W  115 KT 130 MPH
 36H  28/0600Z 25.3N  83.9W  120 KT 140 MPH
 48H  28/1800Z 26.7N  83.5W  115 KT 130 MPH
 60H  29/0600Z 27.5N  83.2W  100 KT 115 MPH
 72H  29/1800Z 28.1N  82.9W   75 KT  85 MPH
 96H  30/1800Z 30.1N  82.3W   45 KT  50 MPH...INLAND
120H  01/1800Z 33.5N  82.0W   25 KT  30 MPH...INLAND

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