It hit the eastern coast as a hurricane, threatening to bring torrential rains and strong winds to a region prone to flash floods and mudslides.
A few hours later, the Atlantic season's first hurricane was downgraded to a tropical storm, forecasters said.
Franklin strengthened Wednesday to become a Category 1 hurricane -- with maximum sustained winds of 85 mph.
It was in the Bay of Campeche, in the far southern Gulf of Mexico, when it was classified as a hurricane
It will continue to move inland over the mountains of central Mexico, where torrential rains and strong winds will affect the population from the east coast toward Mexico City. The main threats going forward will be flash flooding and mudslides, the NHC advisory says.
While still a tropical storm on Monday night, Franklin made landfall
on the eastern coast of Mexico's Yucatan Peninsula, the center said. The storm battered Belize and the Yucatan Peninsula with heavy rain and strong winds.
Rainfall totals of up to 8 inches with isolated maximum amounts of 15 inches are possible in various Mexican states, including Tabasco, northern Veracruz and northern Puebla, according to the center.
"These rains will be capable of producing life-threatening flash floods and mudslides," it said.
Forecasters said hurricane-force winds extended up to 35 miles from the center of the storm and tropical storm-force winds extended up to 150 miles.
A hurricane warning has been in effect for the coast of Mexico from Puerto de Veracruz to Cabo Rojo and a hurricane watch is in effect for the coast of Mexico north of Cabo Rojo to Rio Panuco.
A tropical storm warning is in effect for the coast of Mexico south of Puerto de Veracruz to Puerto Dos Bocas and north of Cabo Rojo to Barra del Tordo, according to the center.
A dangerous storm surge could also raise water levels by as much as 6 feet along the coast and to the north of where the hurricane's center will make landfall, the advisory said. This surge could also bring "large and destructive waves."
Hurricane Center officials are advising residents to prepare to "protect life and property" as soon as possible.
Busy Atlantic hurricane season
Hurricane Franklin might be the first of the season in the Atlantic, but it is not expected to be the last by a long shot. The Atlantic could see as many as 19 named tropical systems
this year, according to the National Oceanic and Atmospheric Administration.
"The season has the potential to be extremely active, and could be the most active since 2010," NOAA said.
The administration initially predicted that the ocean could see anywhere from 11-17 named tropical storm systems this year. The 2017 hurricane season officially began June 1 and ends November 30.