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Tropical Depression Thirteen Forecast Discussion

WTNT43 KNHC 070854

Tropical Depression Thirteen Discussion Number   4
NWS National Hurricane Center Miami FL       AL132022
500 AM EDT Fri Oct 07 2022

The structure of the depression has not changed much this morning. 
Based on surface observations and radar data from Curacao, it 
appears the center of the system has passed south of Aruba and moved 
over the far northern Gulf of Venezuela. The deepest convection is 
still confined to the southern and western portions of the 
circulation. There has been a slight increase in convection well to 
the north of the center during the past several hours, but it lacks 
organization at this time. Unfortunately, the center of the 
depression was not sampled by overnight ASCAT data swaths. Recent 
subjective satellite estimates from SAB and TAFB range from 30-35 
kt, and the initial intensity is held at 30 kt for this advisory. An 
Air Force Reserve Hurricane Hunter aircraft is scheduled to 
investigate the system this morning.

The depression is still moving westward at 280/13 kt. A low- to 
mid-level ridge entrenched over the western Atlantic and the Gulf of 
Mexico will remain the primary steering mechanism for the next few 
days. This ridge should keep the cyclone on a westward heading as it 
crosses the southwestern Caribbean Sea and approaches the coast of 
Nicaragua later this weekend. The steering flow is consistent among 
the global models, and the track model guidance remains tightly 
clustered through landfall. Then, the system is forecast to reach 
the western extent of the ridge and gradually turn toward the 
west-northwest at 72-96 h as it moves across Central America. Due to 
the consistency in the track guidance, the latest NHC forecast is 
essentially an update of the previous one. 

Given the cyclone's proximity to land, only gradual strengthening is 
forecast in the near term as the cyclone passes near or over the 
Guajira Peninsula. Still, the depression is expected to become a 
tropical storm later today. Once the system moves away from land and 
reaches the warm waters of the southwestern Caribbean Sea, the 
atmospheric and oceanic conditions should support a faster rate of 
intensification. Generally weak to moderate deep-layer shear is 
forecast as the cyclone moves within a moist and unstable 
environment, and the multi-model intensity guidance consensus 
supports the cyclone becoming a hurricane by 48 h. In fact, 
conditions should remain generally favorable for intensification 
through landfall, and the official NHC forecast lies on the higher 
end of the models near the HFIP corrected consensus (HCCA). After 
moving inland, the system is expected to weaken over the terrain of 
Central America and dissipate early next week.

Key Messages:

1. Tropical storm conditions are expected across portions of the
Guajira Peninsula of Colombia this morning. Gusts to tropical storm 
force are possible across Aruba and portions of northern Venezuela 
during the next several hours.

2. The system is forecast to strengthen into a hurricane when it 
moves over the southwestern Caribbean Sea. A Hurricane Watch is in 
effect for San Andres, Providencia, and Santa Catalina Islands. 
Interests in Nicaragua and Honduras should monitor the system's 
progress, as additional watches or warnings are likely to be 
required for portions of these areas later today.

3. Heavy rainfall could cause life-threatening flash flooding over 
portions of the Guajira Peninsula, northern Venezuela, and the 
island chain of Aruba, Bonaire, and Curacao during the next day or 
two. The potential for flash flooding and mudslides is expected to 
spread to portions of Central America this weekend.


INIT  07/0900Z 12.1N  71.1W   30 KT  35 MPH
 12H  07/1800Z 12.7N  73.5W   35 KT  40 MPH
 24H  08/0600Z 13.1N  76.5W   45 KT  50 MPH
 36H  08/1800Z 13.2N  79.5W   60 KT  70 MPH
 48H  09/0600Z 13.2N  82.0W   75 KT  85 MPH
 60H  09/1800Z 13.5N  84.3W   55 KT  65 MPH...INLAND
 72H  10/0600Z 14.1N  86.7W   30 KT  35 MPH...INLAND
 96H  11/0600Z 16.0N  91.5W   25 KT  30 MPH...POST-TROP/INLAND
120H  12/0600Z...DISSIPATED

Forecaster Reinhart

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