The first tropical storm warning of this year’s hurricane season was issued early Tuesday, as coastal communities in southern Texas prepare for an oncoming bout of heavy rain and possible flooding. The storm was developing over the southern Gulf of Mexico and expected to reach land as a potential tropical cyclone, according to the National Hurricane Center. 

If the storm becomes strong enough it will become the first named storm of the season: Tropical Storm Alberto.

The tropical storm warning covers coastal Texas areas from Port O’Connor to the mouth of the Rio Grande and extends downward along the Gulf Coast of Mexico. Rainfall linked to the potential tropical cyclone was expected to affect large parts of Central America, too.

Although a map released by the National Hurricane Center showed the storm system striking coastal areas just after midnight on Thursday, meteorologists noted that the impacts would likely be felt on land sooner than that. The latest forecasts indicated that the system would likely increase in strength over the next 36 hours before becoming a tropical storm.

“The disturbance is very large with rainfall, coastal flooding, and wind impacts likely to occur far from the center along the coasts of Texas and northeastern Mexico,” the hurricane center said in a Tuesday advisory. 

In Texas, the hurricane center said moderate coastal flooding could begin along the coast as soon as Tuesday morning and continue through the middle of the week. The situation was forecast to worsen on Wednesday for people in the tropical storm warning area.

The annual Atlantic Hurricane Season officially began on June 1 and will run through the end of November, with most storm activity typically happening during the later months of that window, between mid-August and mid-October.

The National Hurricane Center upgraded what had been the current season’s first tropical storm watch to a tropical storm warning at 4 a.m. CT on Tuesday. The difference accounts for timing — forecasters will generally issue a “watch” when tropical storm conditions are possible in the impacted area within roughly 36 hours, and a “warning” when the conditions become more imminent, about 24 hours out.