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Hurricane Ian Forecast Discussion


699 
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




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