Atlantic Basin Tropical Cyclones

Potential Tropical Cyclone Thirteen Forecast Discussion


346 
WTNT43 KNHC 061453
TCDAT3

Potential Tropical Cyclone Thirteen Discussion Number   1
NWS National Hurricane Center Miami FL       AL132022
1100 AM AST Thu Oct 06 2022

A broad area of low pressure continues to move westward across the 
far southeastern Caribbean Sea, with an expansive area of deep 
convection stretching across northern South America and the 
adjacent waters.  The system does not appear to have a well-defined 
center and therefore cannot yet be designated as a tropical 
depression.  However, the risk of tropical storm force winds has 
increased for portions of the northern coast of South America, and 
advisories are therefore being initiated on Potential Tropical 
Cyclone Thirteen.  The initial intensity is 30 kt based on ASCAT 
data from last evening.

With the low remaining broad, the center is difficult to locate.  
It's estimated to be over water just north of Venezuela based on 
extrapolation, although it should be noted that stronger turning is 
becoming evident in the cloud pattern a little farther south over 
land.  The track forecast reasoning is straightforward.  Strong low- 
to mid-level ridging over the western Atlantic and Gulf of Mexico is 
expected to steer the disturbance westward along the northern coast 
of South American and then across the southwestern Caribbean Sea 
during the next 3 day or so, likely reaching the coast of Central 
America sometime on Sunday.  The track guidance is tightly clustered 
during that period, with a little bit of speed differences, and the 
official forecast track lies close to the TVCN and HCCA consensus 
aids.

Land interaction will likely modulate the system's development over 
the next 24 hours or so, both its designation as a tropical cyclone 
and potential intensification.  Intensity guidance is in fairly 
good agreement that a well-defined center could form by tonight, 
assuming the system is still over water, with winds potentially 
increasing to tropical storm force by Friday morning.  Once the 
system clears land on Friday, low to moderate shear and warm waters 
of 29 to 30 degrees Celsius should foster more significant 
development, with the system forecast to become a hurricane before 
it reaches the coast of Central America on Sunday.  The NHC 
intensity forecast is near a blend of the IVCN and HCCA consensus 
aids, although it's important to note that some intensity models, 
including HWRF and the ECMWF-based SHIPS, are as much as 15 kt 
higher at 72 hours.

Key Messages:

1. Tropical storm conditions are expected across portions of the 
Guajira Peninsula of Colombia tonight and early Friday, where a 
Tropical Storm Warning has been issued.  Gusts to tropical storm 
force are possible across portions of northern Venezuela, Aruba, 
Curacao, and Bonaire through early Friday.

2. The system is expected to strengthen when it moves over the 
southwestern Caribbean Sea, and interests in San Andres, 
Providencia, and portions of Central America should closely monitor 
its progress.  Watches could be required for portions of that area 
later today or tonight.

3. Heavy rainfall could cause life-threatening flash flooding in 
portions of the Guajira Peninsula of Colombia, northern Venezuela, 
Aruba, Bonaire and Curacao during the next day or so.  Heavy 
rains, and the potential for flash flooding and mudslides, are 
expected to spread to portions of Central America this weekend.


FORECAST POSITIONS AND MAX WINDS

INIT  06/1500Z 11.4N  67.0W   30 KT  35 MPH...POTENTIAL TROP CYCLONE
 12H  07/0000Z 11.8N  69.0W   30 KT  35 MPH...TROPICAL DEPRESSION
 24H  07/1200Z 12.3N  71.9W   35 KT  40 MPH...NEAR GUAJIRA PENINSULA
 36H  08/0000Z 12.9N  74.9W   40 KT  45 MPH...OVER WATER
 48H  08/1200Z 13.0N  78.0W   50 KT  60 MPH
 60H  09/0000Z 12.9N  80.6W   60 KT  70 MPH
 72H  09/1200Z 12.8N  82.7W   70 KT  80 MPH
 96H  10/1200Z 13.8N  86.8W   45 KT  50 MPH...INLAND
120H  11/1200Z 15.6N  91.2W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Berg




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