On May 25, the NHC began to track thunderstorms associated with an elongated surface trough located over Florida and the adjoining Atlantic Ocean for potential development into a tropical cyclone, but did not expect formation due to strong upper-level winds and the high potential for the disturbance to move inland. However, contrary to predictions, the system organized after moving northwards, which in turn was contributed to an increase convection and winds within the system. Based on NWS Doppler radar data from Charleston and buoy data, the NHC initiated advisories on Tropical Storm Bertha at 1200 UTC on May 27. Bertha continued to rapidly strengthen despite its proximity to land. One hour after the first advisory was issued, Bertha made landfall on the South Carolina coast with winds of 50 mph. From formation until landfall, Bertha had an unusually small field of gale-force winds, stretching only 25 miles from the center. Bertha began to weaken rapidly once inland, becoming a tropical depression just hours after landfall. Bertha quickly degenerated to a post-tropical remnant over West Virginia at 9:00 UTC on May 28. The remnants of this storm transitioned into an extratropical cyclone and enlarged in size. The cyclone, associated with a cold front brought heavy rainfall, thunderstorms and flooding to the Great Lakes region before being absorbed by a larger extratropical system a day later over southern Quebec.
Preparations
The NHC warned that regardless of development, the precursor disturbance could cause flash flooding, dangerous marine conditions, and life-threatening surf and rip currents. Since the development of Bertha was very unexpected, tropical storm warnings were issued for parts of for the coast of South Carolina from Edisto Beach to South Santee River only an hour before landfall. The National Hurricane Center warned that given very saturated antecedent conditions, rainfall from Bertha can produce life-threatening flash flooding and river flooding.
Impact
Total economic losses from Tropical Storm Bertha were expected to be over $200 million.
Florida
The precursor disturbance to Tropical Storm Bertha caused a significant, multi-day rainfall event across South Florida, with accumulations of across several locations, and with a maximum 72-hour accumulation of in Miami. Rainfall rates of an hour contributed to a 24-hour total of there, more than doubling the previous daily rainfall record and resulting in the city's most significant rain event in eight years. In and around Miami, the rains contributed to the inundation of homes and roadways, especially in close proximity to canals. Some homes even reported partial roof collapses throughout Hallandale Beach and Hollywood as a result of the heavy precipitation. Local police in El Portal asked that the South Florida Water Management District open floodgates to relieve flooding in those canals. In Hialeah, several vehicles were stranded in flooded roadways, prompting several water rescues. The mayor asked residents to remain indoors accordingly. Days of heavy rainfall prompted local National Weather Service offices to issue flash flood warnings, and sporadic severe thunderstorms prompted additional advisories. An EF1 tornado caused primarily tree and fencing damage in southern Miami, though several campers were also overturned. Gusts associated with the disturbance in Florida topped out at near Key Biscayne, Florida. Even as the system progressed north away from Florida, the outer fringes of Tropical Storm Bertha contributed to stormy weather across the state on May 27, therefore forcing the cancellation of the planned Crew Dragon Demo-2 launch.
South Carolina
Bertha brought moderate flooding to Charleston, South Carolina after it made landfall. Minor power outages occurred throughout the state. A drowning was reported in Myrtle Beach due to rip currents from Bertha after the storm made landfall.
Virginia
Across Virginia, significant flash flooding and heavy rainfall associated with the system’s remnants caused an estimated US$1 million in damage.
