A tropical depression continued to spin along the Gulf Coast of Florida as of late morning July 20, according to the National Hurricane Center.

The system, which had formed on Sunday, July 19, remained a tropical depression as of the 11 a.m. ET update from the hurricane center — but was "getting better organized."

Tropical storm watches were expanded for portions of the Gulf Coast. According to the hurricane center, "a tropical storm watch is in effect for Ochlockonee River, Florida, westward to the Jefferson/Plaquemines Parish border in Louisiana."

As of late morning July 20, the storm had maximum sustained winds of 35 mph and was located 120 miles south of Panama City, Florida, the hurricane center said.

Forecasters said the storm is expected to strengthen into a tropical storm as it nears the Gulf Coast, including the Florida Panhandle and coast of Alabama.

If it does become a tropical storm, it would be called Bertha, the second named storm of the Atlantic hurricane season. (Tropical Storm Arthur, in June, was the season's first named storm.)

While the storm is expected to intensify, forecasters said Saharan dust and strong wind shear would likely prevent it from becoming a hurricane, according to Naples Daily News, part of the USA TODAY Network.

Communities along the Gulf Coast, including Florida, Alabama, Mississippi and Louisiana, should monitor the system, the National Hurricane Center advised, as it's expected to bring high winds and heavy rains. The hurricane center warned of possible flash flooding from western Florida to the Texas coast.

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A tropical depression forms when low pressure, accompanied by thunderstorms, produces a circular wind flow with maximum sustained winds below 39 mph, according to NASA. The depression becomes a tropical storm when circulating winds become more organized and increase to gusts between 39-73 mph.

Storm season: Powerful El Niño will crush hurricane development, new outlook says

An "Atlantic Niña" climate pattern, a rare phenomenon, has appeared in the tropics over the last few weeks as a powerful Super El Niño builds in the Pacific, according to the Severe Weather Europe website.

Climate.gov describes Atlantic Niña as a cooling of sea-surface temperatures in the Atlantic Ocean's equatorial waters that can alter rain and wind patterns across the tropics and sometimes influence Atlantic hurricane activity. Its effects are generally weaker and more localized than the Pacific's La Niña.

According to a report on the Severe Weather Europe website, "a rare 'Atlantic Niña' has appeared in the tropics, just as a powerful Super El Niño continues to build in the Pacific. These two ocean anomalies may look opposite on the map, but their atmospheric impact is pushing in the same direction, creating an atmospheric shield for the United States hurricane season."

Contributing: Christopher Cann

This article originally appeared on USA TODAY: Alerts expanded as tropical depression gets 'better organized' in Gulf