A newly formed tropical storm is forecast to enter the record-warm Gulf of Mexico and strengthen into a hurricane before striking Florida's Gulf Coast Tuesday night into Wednesday. The storm — named Idalia — could rapidly intensify before probably coming ashore between Tampa Bay and Panama City.

"There is an increasing risk of life-threatening storm surge, flooding from heavy rainfall, and hurricane-force winds along portions of the west coast of Florida and the Florida Panhandle beginning as early as Tuesday," the National Hurricane Center wrote Sunday. "Storm surge and hurricane watches may be required for portions of the Gulf Coast of Florida later today."

The Hurricane Center projects Idalia will come ashore with peak winds around 90 mph, but some models suggest it could be stronger, nearing major hurricane strength with winds over 110 mph.

"There's a notable risk of rapid intensification while the system moves across the record warm eastern and northeastern Gulf of Mexico," the Hurricane Center cautioned Sunday morning. "The upward overnight model trend certainly bears watching."

Storms that begin with the letter "I" — which often coincide with the peak of hurricane season — have a history of causing severe damage, with Irma (2017), Ida (2021) and Ian (2022) recent examples.

Ahead of the storm on Saturday, Florida Gov. Ron DeSantis (R) declared a state of emergency for 33 counties along its Gulf Coast.

Tampa, Panama City, Tallahassee, Pensacola and Mobile, Ala., are all in the zone that needs to closely watch the system. Current projections suggest the most likely spot for a landfall would be around the Big Bend of Florida. However, shifts in the forecast track are possible and storm impacts can occur hundreds of miles from the center.

"Residents in these areas should monitor updates to the forecast of this system and ensure that they have their hurricane plan in place," the Hurricane Center said.

The Sunshine State is at greatest risk for impacts from an ocean surge, flooding rains, destructive winds and tornadoes, but the storm could also deliver strong winds, heavy rain and a risk of flooding to the Southeast by Wednesday, including Alabama, Georgia and the Carolinas.

The Hurricane Center forecasts 3 to 6 inches of rain, with localized amounts up to 10 inches, for portions of Florida's west coast and panhandle as well as southern Georgia.

"Scattered flash and urban flooding can also be expected across portions of the west coast of Florida, the Florida Panhandle and portions of the Southeast U.S. by Tuesday into Thursday," the Hurricane Center said.

Tropical storm warnings are already in effect in Mexico's Yucatán Peninsula from Tulum to Rio Lagartos, including Cozumel, as well as on the western tip of Cuba, specifically Pinar del Rio. Those areas will first experience the developing storm.

Experts warned that the 2023 Atlantic hurricane season was favored to be above average due to extremely warm sea surface temperatures. Hurricane activity historically picks up markedly toward late August into September and, right on cue, a formidable threat is brewing.

The storm now

On Sunday morning, the system — centered about 80 miles east-southeast of Cozumel — became as tropical storm as its peak winds increased from 35 to 40 mph.

Infrared satellite revealed considerable convection, or thunderstorm activity, a sign of a strengthening system.

The initial question was whether the system featured a coherent closed circulation, or low-level swirl, but radar out of Cancún depicted a well-defined central vortex and Hurricane Hunter aircraft sampled winds commensurate with a tropical storm.

A recipe for strengthening

Over the next 12 to 18 hours, Idalia will remain largely stationary, wobbling a little bit but covering little ground. Then it will begin to work north. It will be squeezed toward the northern Gulf in between a counterclockwise-spinning low pressure system to the west and a zone of high pressure to the east. That atmospheric squeeze play will afford Idalia little ability to avoid the northern Gulf.

Water temperatures across the Gulf of Mexico support intensification. They're running 2 to 4 degrees above average, and average temperatures are already hot enough to foster strengthening.

The only limiting factor would be possible interference Monday from an upper-air disturbance, which would bolster wind shear, or a disruptive change of wind speed and/or direction with height. That would work to knock Idalia off kilter. That said, the effects of that wind shear look likely to relax into Tuesday, at which point a period of rapid intensification may occur.

Because of the warm waters, there's a chance that Idalia could come ashore stronger than the current forecast. High-resolution computer models indicate the storm could even reach at least Category 3 intensity. For now, the Hurricane Center is projecting a high-end Category 1 landfall.

Jason Samenow contributed to this report.