Tropical cyclone development over the Gulf of Mexico is becoming increasingly likely late this week or early this weekend. The National Hurricane Center (NHC) has issued a Special Tropical Weather Outlook (STWO) for a weak surface trough currently located over the Northwestern Caribbean Sea, giving the disturbance a near zero percent chance of development within 48 hours and a 20 percent chance within five days. Although upper-level winds are not expected to be conducive for a strong storm, a sheared tropical storm could develop over the east-central Gulf of Mexico and make landfall anywhere between Louisiana and the Florida Peninsula this weekend. Since a low-level circulation has not formed, the eventual track of this disturbance or tropical cyclone remains highly uncertain.

Of the 12z Monday models, the ECMWF, CMC, and UKMET models all produced a tropical storm to develop over the central or eastern Gulf of Mexico by Saturday. The 12z GFS continued to show no significant development with a much farther east track into the southern Florida Peninsula as a broad low pressure area.  The ECMWF model shifted slightly east compared to the 00z run, but still predicts a landfalling tropical storm near New Orleans, Louisiana. We should have a better handle on the track and intensity of this system by the middle of the week, but residents along the Gulf Coast from Louisiana to Florida should closely monitor the development of this system.

The main threat, as is typical with early season large, disorganized systems, is heavy rain – mostly to the the east of the center due to moderate to strong wind shear. Isolated tornadoes are also possible, especially in the right-front quadrant if a tropical cyclone develops. Regardless of development, heavy rains are likely in the Gulf Coast and Southeastern United States over the Memorial Day holiday weekend.

I will be back with a post on this system tomorrow, as well as my 2018 Atlantic hurricane season May forecast update. The official start of the 2018 Atlantic hurricane season is only 11 days away, on June 1. If this system becomes a tropical storm, it will be named Alberto.