A hurricane hunter aircraft dispatched to investigate the tropical depression this afternoon reported that maximum sustained winds near the storm center had increased to near 40 mph, enough to categorize it as a tropical storm. Forecasters at the National Hurricane Center expect Sandy to strengthen over the next 48 hours, meaning it could be a hurricane by the time it reaches Jamaica on Wednesday.

As of 4 p.m. CDT Monday, Tropical Storm Sandy was about 395 miles south-southwest of Jamaica’s capital, Kingston. The storm was stationary, but is expected to begin moving toward the north-northeast over the next two days.

The NHC said Sandy could dump an average of 5-10 inches of rain on Jamaica, Haiti, the Dominican Republic, and eastern Cuba. Mountainous regions could see up to 16 inches of rainfall.

“These rains may produce life-threatening flash floods and mudslides,” the NHC noted.

No cruise ships appear to be in imminent danger from the storm. Holland America’s MS Zuiderdam was well to the east of Sandy, near Aruba.