Millions on alert as Tropical Storm Arthur threat grows with life-threatening impacts on US coast

Forecasters are keeping a close watch on a disturbance in the Gulf of America, warning it could strengthen into a tropical storm as early as Tuesday.

The National Hurricane Center (NHC) said the odds of Invest 90L, a disturbance being closely monitored for tropical development, strengthening into a tropical depression have risen to 60 percent, up 10 percentage points from Monday.

A tropical depression is a weaker, less organized system with maximum sustained winds of 38 mph or less, and a tropical storm is defined as a more organized and intense system with sustained winds between 39 and 73 mph.

If the system reaches tropical storm strength, it would become Arthur, the first named storm of the 2026 Atlantic hurricane season.

The NHC said Tropical Storm Watches or Warnings could be issued later Tuesday and warned that the system has a medium chance of tropical cyclone formation within the next 48 hours.

Residents across southern and eastern Texas, as well as parts of Louisiana and Mississippi, should prepare for periods of intense rainfall over the coming days regardless of whether the system develops into a tropical cyclone.

Forecasters warned that widespread, life-threatening flash, urban and river flooding is possible, along with gusty winds and coastal flooding along portions of the northwestern Gulf Coast.

Meteorologist Dylan Federico said on X: 'Invest 90L is re-emerging back in the Gulf and is likely to become Tropical Storm Arthur before landfall in Louisiana tomorrow night. I’m not liking what I’m seeing from the overnight model data.'

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Meteorologist Andrew Shipotofsky said Invest 90L continues to generate a large area of disorganized showers and thunderstorms near the Texas-Mexico border.

He noted on X that as the system moves into the northwestern Gulf later Tuesday, it could briefly organize into a tropical depression or become Tropical Storm Arthur.

AccuWeather is forecasting four to eight inches of rain from southeastern Texas to the central portions of Louisiana, Mississippi and Alabama through Tuesday night alone.

While the rain could provide much-needed relief from drought conditions in some areas, forecasters warn it also raises the risk of dangerous flash flooding.

Parts of the Texas Hill Country were already drenched with two to six inches of rain between Sunday and Monday morning, triggering reports of flash flooding.

By Tuesday night, a tropical rainstorm is expected to form off the Texas coast.

AccuWeather vice president of forecast operations Dan DePodwin said in a statement: 'This area can further amplify the flood risk starting Tuesday night along the Texas coast, extending into the Houston area on Wednesday, which would coincide with the World Cup match that afternoon.

'Although the match is inside, flooding could cause road closures and dangerous travel conditions.'

This is a developing story... More updates to come.