A disturbance over the southwestern Gulf of Mexico now has a 90 percent chance of development, according to the U.S. National Hurricane Center. Tropical storm watches and warnings are already in effect, including for parts of Louisiana, Alabama and the Florida Gulf Coasts. For more details on this system, see below.
THE BREWING STORM IN THE GULF
This system is being described as a "complicated weather situation" over the Gulf of Mexico and currently has neither sufficient convection or a well-enough defined center to be designated a tropical or subtropical cyclone. Environmental conditions are expected to be favourable for additional development while the system moves generally northeastward over the western Gulf of Mexico.
LANDFALL THIS WEEKEND WITH STRONG WINDS AND FLOODING RAINS
The system is expected to approach the northern or northeastern Gulf Coast on Friday or Saturday and regardless of development, it will likely produce gusty winds and rough surf over those areas.
Heavy rainfall is also possible across portions of the southeast U.S. through this weekend, with as much as 150 mm possible in the hardest hit areas.
FAVOURABLE CONDITIONS IN THE GULF OF MEXICO
Sea surface temperatures near the Gulf of Mexico and U.S. coast are warm after the summer and early fall season, which creates a very favourable environment for tropical systems to develop. As we approach the winter months these waters will cool and will make it increasingly difficult to sustain a tropical system.
Another favourable factor that will contribute to the development of this system is that there is very little windshear present over the gulf. Windshear can tear apart tropical systems, while it favours severe thunderstorms.
While an October landfall may seem rare, we only have to think back to last year's Hurricane Micheal, a devastating Category 5 storm and Hurricane Matthew, which made its first landfall over Haiti's Tiburon Peninsula on October 4, 2016.
With files from the U.S. National Hurricane Center.