Cyclone the storm is predicted to escalate to a uncommon Category 5 hurricane as it turns towards the Caribbean island, causing deadly rapid inundation and landslides.
This weather system, which registered winds of up to 120 miles per hour as of 6:00 AM GMT, is currently turning north-west in the Caribbean Sea and is projected to make landfall by Tuesday, based on data from meteorological authorities.
Warnings of power cuts and damage to infrastructure have been announced as Melissa produces up to 30 inches of rainfall and sea level surges as high as 13ft above normal levels. "Take cover without delay," inhabitants have been advised.
Melissa is the 13th storm in the current Atlantic hurricane season, which typically ends in late autumn.
A category five storm is the most powerful category, with sustained winds of at least 157 miles per hour.
Although this storm is expected to diminish in strength to a category four cyclone before making landfall on the island, meteorologists said there was "minimal real distinction in the total effects" upon reaching the coast, and that the hurricane will be "equally strong" when it hits the nation.
With storm-force wind and rainfall already expected long before it moves across the island's interior - perhaps encompassing the national capital - advisories indicate that "preparations should be rushed to completion".
"Several days of harmful winds and heavy rainfall have begun and will cause catastrophic and life-threatening flash flooding and numerous mudslides," counseled climate experts.
The nation's leader the official said: "I understand that there are many Jamaicans who are anxious, who are deeply troubled, and appropriately: worry is natural.
"Yet the most effective method to handle anxiety and any nervousness and worry is to stay ready."
Inhabitants are being advised to secure their homes with protective bags and timber panels, and to accumulate basic necessities.
Advisories are also in effect for regions of Haiti including the main city, Port au Prince, the Dominican Republic and eastern Cuba, where Melissa is expected to bring analogous consequences by the midweek period.
Mudslides already being caused by the cyclone have resulted in two fatalities in Haiti, according to emergency services.
The hurricane is forecast to cross Cuba by Wednesday before traveling via the Caribbean archipelago and emerging into the Atlantic.
By the moment it arrives at Cuba, it is forecast to have diminished to a third-level cyclone.
Although it is hard to connect specific storms to climate change, experts say it is resulting in weather phenomena more common and more severe.
Warmer oceans generate additional humidity in the air, contributing to the development of tropical cyclones.
Before the start of this season's Atlantic hurricane season, meteorological authorities predicted increased storm frequency, citing warmer seas and possible enhanced seasonal rains around West Africa - where tropical systems often form.