[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 281537 CCA
TCDAT5

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

Corrected a typo.

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 shear 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.

KEY MESSAGES:

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.

FORECAST POSITIONS AND MAX WINDS

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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