Potential Tropical Cyclone Nine Forecast Discussion

845 
WTNT44 KNHC 232053
TCDAT4

Potential Tropical Cyclone Nine Discussion Number   2
NWS National Hurricane Center Miami FL       AL092024
500 PM EDT Mon Sep 23 2024

Showers and thunderstorms associated with the disturbance are 
gradually becoming better organized this afternoon, although the 
convection is mostly confined to the eastern portion of the 
circulation. Scatterometer winds and aircraft data indicate the 
disturbance still lacks a well-defined center, with very light winds 
noted on the west side of the broad, elongated circulation. The 
scatterometer data did show stronger winds near the convection on 
the east side, and based on this along with the aircraft winds, the 
initial intensity is raised to 30 kt for this advisory.

The estimated initial motion is north-northwestward (345/6 kt), but 
the disturbance should turn more northwestward during the next day 
or so. The NHC forecast shows the center of the system passing 
between the Yucatan Peninsula and the western tip of Cuba late 
Tuesday night, then moving into the southern Gulf of Mexico on 
Wednesday. From there, the flow between a deep-layer trough over the 
central United States and a ridge over the western Atlantic should 
cause the system to accelerate northward to north-northeastward 
across the eastern Gulf of Mexico and toward the northeastern Gulf 
Coast and Florida Panhandle through Thursday. The track guidance is 
very tightly clustered on this solution, and the official NHC 
forecast is essentially an update of the previous one.  

The moderate southwesterly shear over the disturbance is expected to 
diminish over the next day or two, which should allow the system to 
become better organized and consolidate over deep, warm waters in a 
very moist environment. Once the system develops an inner core, 
these conditions should allow it to significantly strengthen. The 
NHC forecast still calls for the system to become a hurricane on 
Wednesday, with continued intensification thereafter while it moves 
over the eastern Gulf of Mexico. Once again, the statistical RI 
guidance (SHIPS and DTOPS) show a 65-kt increase in 72 h is very 
likely, and the updated NHC forecast now explicitly shows the system 
reaching major hurricane intensity on Thursday. This intensity 
forecast still lies below the consensus aids, with the regional 
hurricane models and the GFS showing even more deepening.

Note that the system is expected to grow in size while it traverses 
the Gulf. Thus, the storm surge, wind, and rainfall impacts will 
extend well away from the center, particularly to the east of the 
system. In addition, the fast forward speed as it approaches the 
coast will likely result in farther inland penetration of gusty 
winds over parts of the southeastern United States after landfall. 


KEY MESSAGES:

1. The disturbance is forecast to intensify and be near hurricane 
strength when it reaches the far northwestern Caribbean Sea Tuesday 
night. Tropical storm conditions are expected over portions of 
western Cuba and the northeastern coast of the Yucatan Peninsula 
with hurricane conditions possible. 

2. The system is expected to intensify into a major hurricane 
before it approaches the northeastern Gulf Coast on Thursday. While 
it is too soon to pinpoint the exact location and magnitude of 
impacts, the potential for life-threatening storm surge and 
damaging hurricane-force winds along the coast of the Florida 
Panhandle and the Florida west coast is increasing. Storm Surge 
and Hurricane Watches will likely be issued for a portion of that 
area tonight or Tuesday morning, and residents should ensure they 
have their hurricane plan in place.

3. Potential Tropical Cyclone Nine will bring heavy rain to portions 
of the western Caribbean which may lead to flooding and possible 
mudslides in western Cuba.


FORECAST POSITIONS AND MAX WINDS

INIT  23/2100Z 18.1N  82.2W   30 KT  35 MPH...POTENTIAL TROP CYCLONE
 12H  24/0600Z 19.0N  83.0W   35 KT  40 MPH...TROPICAL CYCLONE
 24H  24/1800Z 19.9N  84.2W   45 KT  50 MPH
 36H  25/0600Z 21.1N  85.4W   55 KT  65 MPH
 48H  25/1800Z 23.0N  86.0W   75 KT  85 MPH
 60H  26/0600Z 25.4N  85.5W   90 KT 105 MPH
 72H  26/1800Z 28.9N  84.5W  100 KT 115 MPH
 96H  27/1800Z 35.5N  84.5W   30 KT  35 MPH...POST-TROP/INLAND
120H  28/1800Z 39.5N  88.5W   20 KT  25 MPH...POST-TROP/INLAND

$$
Forecaster Reinhart