Air carrier flight crew reported the GPWS sounded an alarm as it was descending for an approach.

Attributes
ACN	1318760
Time
Date	201512
Local Time Of Day	1201-1800
Place
Locale Reference	MRLB.Airport
State Reference	FO
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	Large Transport
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	STAR COTAL NORTH
Flight Plan	IFR
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Inflight Event / Encounter CFTT / CFIT Inflight Event / Encounter Weather / Turbulence

Narrative:

On the cotal north arrival in VMC we requested and received approval to descend to 1;700ft and direct to cotal on the ILS DME 07 in mrlb. We were experiencing light to moderate turbulence at altitude and we decided that a lower altitude would provide the passengers a better ride. We were following the coast line over the water and descending. About 20 miles to the north of the airport there is a peninsula that extends further out from the coast line. We were fully aware of it and we had out egpws selected. We discussed it and our decision was to fly further west of it. The GPWS was two steps ahead. This triggered the GPWS terrain warning. We then climbed and turned to the right leaving the auto pilot on. The system worked as designed.

Original NASA ASRS Text

Title: Air carrier flight crew reported the GPWS sounded an alarm as it was descending for an approach.

Narrative: On the COTAL NORTH arrival in VMC we requested and received approval to descend to 1;700ft and direct to COTAL on the ILS DME 07 in MRLB. We were experiencing light to moderate turbulence at altitude and we decided that a lower altitude would provide the passengers a better ride. We were following the coast line over the water and descending. About 20 miles to the North of the airport there is a peninsula that extends further out from the coast line. We were fully aware of it and we had out EGPWS selected. We discussed it and our decision was to fly further west of it. The GPWS was two steps ahead. This triggered the GPWS terrain warning. We then climbed and turned to the right leaving the auto pilot on. The system worked as designed.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.