An excerpt from the detailed tropical weather forecast discussion:
Increasing thunderstorm activity, strong gusty winds, and building sea heights will accompany a tropical wave as it moves across the Tropical Atlantic Ocean waters and the lesser Antilles this evening and tonight. It is possible that a surface low pressure center may develop along the northern part of the tropical wave from Monday through Tuesday, as it continues westward across the E Caribbean Sea and the adjacent Atlantic Ocean.
https://www.nhc.noaa.gov/text/MIATWDAT.shtml

Translated: The possible development of the wave into an organized tropical or sub-tropical system is forecast to take place after it has passed over St. Maarten.