Resolution source: https://www.nhc.noaa.gov/archive/2026/ Subtropical storm also counts. Resolves to the UTC time written in the advisory text. N/A if does not form in 2026. Will add days to the answers as needed.

Per Manifold Markets prediction market, July 20, followed by July 19 and July 21 are most likely. See the market for live updates (1 traders, as of Jul 20, 2026).

When will Tropical Storm Bertha form? (AL)

Looking like at least a TS landall in the Gulf is likely per GGL/00Z (and a small chance of a Hurricane landfall at the moment as well). Worth watching...

ABNT20 KNHC 191120
TWOAT 

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Sun Jul 19 2026

For the North Atlantic...Caribbean Sea and the Gulf of America:

Northern Gulf of America and near Florida (AL91):
An area of low pressure located over the northeastern Gulf of 
America continues to become better defined and the associated shower 
and thunderstorm activity is gradually increasing.  Continued 
gradual development is expected, and a tropical depression is likely 
to form later today or on Monday as the system moves slowly 
northward or northwestward.  Interests along the northern Gulf coast 
from Florida, Alabama, Mississippi, and Louisiana should monitor 
the progress of this system, as tropical storm watches or warnings 
could be required for portions of the area later today.  In 
addition, this system is expected to bring heavy rains to portions 
of the northern Gulf coast during the next several days.  An Air 
Force Reserve reconnaissance aircraft is scheduled to investigate 
the low pressure area later today.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 7 days...high...80 percent.

$$
Forecaster Cangialosi

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