Tropical Storm Bertha Update | Carolinas Flood Threat

After yesterday's On the Radar update on Tropical Depression Two, the system strengthened into Tropical Storm Bertha around 8 p.m. ET on July 20. In today's blog, we'll provide the latest update on Bertha's impacts along the northern Gulf Coast and discuss a growing flash flood threat across the Carolinas later this week.

Tropical Storm Bertha

Bertha remains an asymmetric storm, with the deepest convection and heaviest rainfall displaced south of the center because of persistent northerly wind shear. You can see this clearly in the visible satellite image below.

Bertha strengthened into a 60 mph tropical storm by 11 a.m. ET on July 21. Although much of the heavy rain has remained offshore, wind gusts over 50 mph have been reported across portions of the Florida Panhandle. You can see these observations on our Weatherstem dashboard: 

Persistent northerly wind shear has limited Bertha's organization and kept most of its thunderstorms south of the center. The official National Hurricane Center forecast keeps the storm moving generally westward over the next couple of days while gradually weakening.

Despite the expected weakening trend, Bertha will continue to produce several hazards along portions of the northern Gulf Coast over the next couple of days.

Impacts: Rain

Most of Bertha's heaviest rainfall has remained over the Gulf of Mexico, with only the immediate coastline experiencing periods of heavy rain.

Forecast guidance indicates this pattern will continue, with the highest rainfall totals remaining just offshore. However, localized flooding remains possible where heavier rain bands move onshore. 

In addition to heavy rainfall, Bertha will continue producing hazardous marine and beach conditions.

Impacts: Coastal

Dangerous surf and life-threatening rip currents will remain the primary coastal hazards.

In fact, many beaches are closed to swimming as you can see by the double red flags flying in these timelapses from two Weatherstem stations below: 

Some minor surge has been reported but it is expected to stay in that 2-4 ft range over the next couple of days: 

Flooding Potential Increase Across the Carolinas

While Tropical Storm Bertha is drawing much of the attention, the greatest flood threat later this week will actually develop well away from the storm's center. That's the situation developing across the Carolinas into the weekend.

A stalled frontal boundary combined with deep tropical moisture streaming northward from Bertha will create an environment favorable for repeated rounds of thunderstorms across the Carolinas. The increase in atmospheric moisture is evident in the precipitable water forecast from Wednesday morning through Saturday morning below.

Several inches of rain are possible across portions of the Carolinas by Sunday morning, with locally higher amounts where thunderstorms repeatedly move over the same locations: 

While much of the rainfall will benefit areas experiencing drought, periods of intense rainfall could still lead to localized flash flooding, especially in urban areas and other flood-prone locations.

Bottom Line

Tropical Storm Bertha became the second named storm of the 2026 Atlantic hurricane season Monday evening and will continue bringing dangerous rip currents, rough surf, minor coastal flooding, and locally heavy rainfall to portions of the northern Gulf Coast through the next couple of days. Farther east, the greater concern shifts to the Carolinas, where a stalled front interacting with deep tropical moisture is expected to produce several rounds of heavy rain and the potential for localized flash flooding through the weekend. Continue monitoring forecasts from the National Hurricane Center and your local National Weather Service office as conditions evolve.

Weather hazards aren't always confined to the center of a tropical storm. Weatherstem provides emergency managers with real-time weather observations, lightning detection, cameras, and customizable alerts to help maintain situational awareness before, during, and after severe weather events. Reach out to learn more.

Is Tropical Storm Bertha expected to strengthen?

No. While Bertha strengthened into a 60 mph tropical storm, persistent wind shear is expected to weaken the storm over the next couple of days.

Where will Tropical Storm Bertha have the biggest impacts?

The primary impacts include dangerous rip currents, rough surf, minor coastal flooding, gusty winds, and locally heavy rainfall along portions of the northern Gulf Coast.

Why is the Carolinas flood threat not directly from Bertha?

A stalled frontal boundary interacting with deep tropical moisture from Bertha will produce repeated rounds of thunderstorms. This setup can generate heavy rainfall and flash flooding even far from the storm's center.

Could the heavy rainfall benefit drought conditions?

Yes. Much of the Southeast, including portions of the Carolinas, has experienced increasing drought conditions. While the rain should provide beneficial moisture, localized flash flooding remains possible where the heaviest rainfall occurs.