(CNN) -- An "extremely dangerous" Hurricane Jimena bore down Tuesday on the Mexican peninsula of Baja California, with the resort town of Cabo San Lucas lying in its path.
The hurricane's maximum wind speed dropped from 155 mph to 145 mph, but it still remains a Category 4 storm, according to the U.S. National Weather Service's 8 a.m. PT (11 a.m. ET) update.
"Some fluctuations in strength are likely today and gradual weakening is forecast on Wednesday," NWS said. "However, Jimena is expected to remain a major hurricane until landfall."
The storm's center is forecast to come ashore on Thursday morning, but the weather service warned that "because it will be moving parallel to the coastline, any slight change in direction could have a huge impact in the location and timing of landfall."
Mexico's government extended a hurricane warning for most of the southern half of the Baja peninsula -- from Punta Abreojos on the peninsula's west coast to Mulege on its east coast, according to NWS.
A hurricane warning means hurricane conditions are expected within the warning area with the next 24 hours and people should quickly prepare "to protect life and property."
On its current track, Jimena's center will approach the peninsula's southern portion later on Tuesday and approach central Baja California peninsula by Thursday, NWS said at 8 a.m. PT.
In addition to damaging winds, the storm could bring as much as 15 inches of rain, forecasters said.
Jimena -- the 10th named storm of the Pacific season -- was centered about 140 miles (225 km) south-southwest of Cabo San Lucas, according to NWS. It was traveling north-northwest near 12 mph (19 kph).
People in his town of Los Cabos, at the very tip of the peninsula, were preparing for the storm and were getting a precursor as winds and rains began to pick up, said resident Cuauhtemoc Morgan on Monday.
Morgan, who sent videos to to CNN's iReport, said residents had protected every home in his neighborhood, fortifying windows with masking tape. Lines at supermarkets were long with worried residents preparing for the storms, Morgan said.
Authorities were setting up shelters in schools and trying to devise a plan to protect the homeless, Morgan said.