Tropical Storm Idalia Forecast Discussion Number 8

By | August 28, 2023

WTNT45 KNHC 281500

Tropical Storm Idalia Discussion Number   8
NWS National Hurricane Center Miami FL       AL102023
1000 AM CDT Mon Aug 28 2023

The satellite presentation of the storm has improved this morning
with the center more deeply embedded within the deep convection and
colder cloud tops.  However, recent reconnaissance aircraft data
from both the U.S. Air Force Reserve and NOAA indicate that the
improved satellite presentation has not yet resulted in an
increase in wind speed.  The Air Force Hurricane Hunter aircraft
has measured peak 850-mb flight-level winds of 68 kt, and a minimum
pressure around 990 mb.  Based on these data, the initial intensity
remains 55 kt this advisory.  The Air Force aircraft will be in the
storm environment through early afternoon and that data should
continue to provide information Idalia's structure and intensity.

Recent satellite and aircraft fixes show that Idalia is moving
northward or 360/8 kt.  A mid-level trough over the central
Gulf of Mexico and a ridge near the Greater Antilles should cause
Idalia to move northward at a faster forward speed during the next
12-24 hours.  After that time, an even faster north-northeast
motion is expected an another mid-level trough moves across the
central and eastern portions of the United States.  The latest NHC
track forecast is again quite similar to the previous forecast.
Although the track forecast has been quite consistent, there is
still some spread in the guidance by 48 hours, and it cannot be
emphasized enough that only a small deviation in the track could
cause a significant change in Idalia's landfall location in Florida
due to the paralleling track to the west coast of the state.

Although there is still some moderate northwesterly over the storm,
intensification seems likely during the next 12-18 hours, and
Idalia is forecast to become a hurricane during that time.  By
Tuesday, the environment over the eastern Gulf of Mexico is
expected to become more conducive for strengthening.  Steady to
rapid intensification is predicted beginning Tuesday while Idalia
traverses the warm waters of the eastern Gulf and the upper-level
environment becomes more favorable.  The NHC intensity forecast
again calls for Idalia to reach major hurricane strength before
landfall along the Gulf coast of Florida.

This forecast has necessitated the issuance of Storm Surge and
Hurricane Warnings for portions of the west coast of Florida and
Storm Surge and Tropical Storm Watches for portions of the Atlantic
coasts of Florida and Georgia.


1. There is a danger of life-threatening storm surge inundation 
along portions of the Florida Gulf Coast where a Storm Surge Warning 
is in effect, including Tampa Bay and the Big Bend region of 
Florida. Inundation of 7 to 11 feet above ground level is expected 
somewhere between Chassahowitzka and Aucilla River.  Residents in 
these areas should follow any advice given by local officials. 

2. Hurricane conditions are expected within portions of the 
Hurricane Warning area along the Florida Gulf Coast, with the 
potential for destructive winds where the core of Idalia moves 
onshore. Strong winds will also spread inland across portions of 
northern Florida near the track of the center of Idalia.

3. Areas of flash and urban flooding, some of which may be locally 
significant, are expected across portions of the west coast of 
Florida, the Florida Panhandle, and southern Georgia Tuesday into 
Wednesday, spreading into portions of the eastern Carolinas 
Wednesday into Thursday.

4. Hurricane-force winds are expected across portions of far western 
Cuba later today.  Heavy rainfall is also expected across portions 
of western Cuba and may produce areas of flash and urban 
flooding as well as landslides across western Cuba.


INIT  28/1500Z 20.8N  85.2W   55 KT  65 MPH
 12H  29/0000Z 22.0N  85.2W   65 KT  75 MPH
 24H  29/1200Z 23.9N  85.1W   75 KT  85 MPH
 36H  30/0000Z 26.4N  84.6W   90 KT 105 MPH
 48H  30/1200Z 29.2N  83.5W  100 KT 115 MPH
 60H  31/0000Z 31.9N  81.2W   55 KT  65 MPH...INLAND
 72H  31/1200Z 33.6N  78.0W   50 KT  60 MPH...OVER WATER
 96H  01/1200Z 34.6N  71.2W   50 KT  60 MPH
120H  02/1200Z 34.5N  67.0W   50 KT  60 MPH

Forecaster Brown

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