Hurricane Ian’s top winds increased to 105 mph Monday night after strengthening into a Category 2 storm on a path toward western Cuba and Florida’s Gulf coast.

The storm is expected to reach major hurricane strength by early Tuesday, which means winds of at least 111 mph.

At 11 p.m. Monday, Ian was 105 miles east-southeast of Cuba’s western tip, according to an update from the National Hurricane Center, moving north-northwest at 13 mph. After passing over the island, it’s expected to intensify to Category 4 strength, with top winds of 140 mph, and weaken slightly before making landfall on Florida’s Gulf coast. But Ian is still forecast to be at or near major hurricane strength when it passes near the west-central Florida coast on Wednesday and Thursday, the center’s latest advisory said.

Ian’s hurricane-force winds extend up to 35 miles outward from its center while tropical-storm-force winds extend up to 115 miles outward. Ian will move over western Cuba through early Tuesday before emerging in the southeastern Gulf of Mexico, move to the west of the Florida Keys late Tuesday and then approach Florida’s west coast Wednesday and Thursday, the center’s update said.

By Monday evening, Hurricane Ian’s outer bands began to bring rain to the South Florida region, said Shawn Bhatti, a meteorologist for National Weather Service Miami.

“We’re effectively in the outer environment of the storm at this point,” he said.

Ian will bring intermittent to heavy rainfall to the area over the next 12 to 18 hours, Bhatti said, and then heavier rainfall throughout the day Tuesday afternoon and through most of Wednesday.

Tropical storm watches were extended to the Middle Florida Keys and Lake Okeechobee, reflecting the storm’s larger wind field, while a broad area of the Gulf coast braced for the first direct hit on the continental United States of the 2022 hurricane season.

Despite the attention given to high winds, the biggest killer in hurricanes tends to be water. The hurricane center warned Monday that the Gulf coast faces a high risk of storm surge, the rapid increase in sea level that can flood coastal neighborhoods.

“This portion of the coastline — the west coast of Florida — is incredibly vulnerable to storm surge,” said Jamie Rhome, acting director of the National Hurricane Center, speaking at a news conference Monday afternoon outside the hurricane center’s headquarters in Miami. “This is the quintessential case of not focusing on the exact track. You won’t have to have a track for the center to make a direct hit for a significant storm surge on the Florida west coast. We’re indicating a potential for as much as 10 feet of storm surge for portions of the Florida west coast.”

A particularly threatening element of the hurricane comes from storm surge, the wind-driven rise in sea level that can flood coastal areas.

“This looks very threatening for tremendous storm surge into the Tampa Bay area,” said Dan Kottlowski, lead hurricane forecaster for AccuWeather, the private forecasting service.

“The barrier islands would get very impressive storm surge — huge waves, phenomenal waves, waves that people don’t normally see along the west coast of Florida,” he said. “Speaking conservatively, a six-foot storm surge and as much as that in waves, so it could be a 12-foot rise in water. That’s a scenario that you don’t like to think about, but it’s possible.”

Southeast Florida remains outside the cone projecting the likely course of the storm’s center. But winds of tropical-storm force and hurricane force can occur outside the cone, depending on how close to the center comes to the edge of the cone.

All of South Florida is under a flood watch until Thursday morning, the National Weather Service Miami said in a 6 p.m. briefing, with “significant to major flooding” possible across the region through Wednesday.

West Palm Beach, Fort Lauderdale and Miami all have the potential for major flooding rains that could result in flood waters entering structures, stressing flood-control systems, submerging streets and parking lots and closing roads, the weather service’s 6 p.m. briefing said.

Gusts of tropical-storm-force winds are likely to reach South Florida late Tuesday night through Wednesday night with the possibility of a few tornadoes throughout Wednesday, the NWS Miami said. The probability for tropical-force winds for South Florida is 35 to 45%.

The storm is expected to expand as it strengthens, placing a larger area at risk of high winds. These winds can rip off tree branches, knock down power line and blow objects off the ground, the weather service said.

“While a direct landfall to South Florida is unlikely at this time, hazardous conditions can extend well away from the center of the system” the weather service said.

If Ian were to reach major hurricane status, it would be the season’s second major Atlantic hurricane. Fiona, which dissipated Sunday as a remnant low, was 2022′s first major hurricane.

Most of Florida continued to brace for the uncertain path of the intensifying storm.

Tampa Bay and the Anclote River south to Flamingo are under a storm surge warning while storm surge watches are in place for the Florida Keys from the Card Sound Bridge westward to Key West, Dry Tortugas, Florida Bay, Aucilla River to Anclote River, Altamaha Sound to the Flagler and Volusia County line and the Saint Johns River.

Several Cuban provinces, Englewood to the Anclote River, including Tampa Bay, and the Dry Tortugas are under a hurricane warning as of 11 p.m. Monday while a hurricane watch is in place for North of Anclote River to the Suwannee River and Bonita Beach to Englewood.

Tropical storm warnings are in effect for several Cuban provinces, the lower Florida Keys from the Seven Mile Bridge westward to Key West and from Flamingo to Englewood. Tropical storm watches are in place for the Florida Keys from Seven Mile Bridge to Channel 5 Bridge, Lake Okeechobee, north of the Suwannee River to Indian Pass and Jupiter Inlet to Altamaha Sound.

Hundreds of thousands of people on the state’s west coast are under mandatory or voluntary evacuation orders.

The National Weather Service continues to emphasize uncertainty in the storm’s path once it enters the Gulf, and said the storm is expected to expand in size as well. The models show a possible direct hit to the Tampa area all the way through the Florida Panhandle.

Small changes in the path will make a big difference in the impact throughout Florida. In South Florida, widespread rain could lead to major flooding, accompanied by winds gusting up to tropical storm levels.

The National Hurricane Center’s latest advisory said the Florida Keys and coastal southwest and southeast Florida will see between 4 and 6 inches of rain with as much as 8 to 10 inches in some areas. Central west Florida could see a maximum of 20 inches in some areas while northeast Florida will get between 6 and 10 inches with 12 inches in some areas.

The remainder of the central part of the state will get between 4 and 8 inches, the center’s update said.

Forecasters are also monitoring a system in the Atlantic off Africa that is likely to develop into a tropical depression in the next few days as it moves over the central tropical Atlantic, the center said in its 8 p.m. update. It has a 70% chance of developing in the next two to five days but will run into upper-level winds by the end of the week, making it less likely to develop.

What was Tropical Storm Gaston had dissipated by early Monday.

The next named storm to form would be Julia.

Hurricane season ends Nov. 30.

Staff writers David Lyons and Scott Travis contributed to this report.