Tropical Update: Invest 96L Designated in Western Gulf; Likely to Become a Tropical or Subtropical Cyclone

Figure 1. Five-Day Graphical Tropical Weather Outlook from the National Hurricane Center as of 8 PM EDT October 16, 2019.
Figure 1. Five-Day Graphical Tropical Weather Outlook from the National Hurricane Center as of 8 PM EDT October 16, 2019.

The center of the broad area of low pressure that has been traversing Central America for the past few days has emerged into the Bay of Campeche, and has been designated Invest 96L.

Development chance

Environmental conditions in the Bay of Campeche remain favorable tropical or subtropical cyclone formation, and the odds of Invest 96L developing into a tropical or subtropical cyclone have continued to trend upward as a result.

In their 8 PM EDT Tropical Weather Outlook, the National Hurricane Center placed the 2-day development chance at 60 percent and the 5-day development chance at 60 percent.

Model guidance

As of the 12z model cycle, the ECMWF, GFS and UKMET were still in agreement on development of Invest 96L Thursday/Friday.

Track and intensity

With an approaching trough/front this weekend, a northeast track toward the north-central and northeast Gulf Coast is essentially a guarantee (see figure 2).

Figure 2. ECMWF predicted 850 mb vorticity, winds and MSLP for Saturday morning, showing 96L approaching the northern Gulf Coast as a tropical or subtropical storm. Image: Tropical Tidbits

Landfall is looking to be Saturday, but where is uncertain at this juncture, and could occur anywhere from Southeast Louisiana to the Florida Panhandle.

Based on model guidance, it is now probable that 96L will be a tropical or subtropical storm – not a weak low. However, there will be dry air and shear present, meaning significant strengthening is not too likely.

Impacts

The main impact is going to be heavy rain (see figure 3). In addition, coastal inundation (flooding), gusty winds, and severe weather will be potential hazards. Placement is dependent on exact track.

Figure 3. Rainfall forecast through next Wednesday. Image: Pivotal Weather

However, because this will probably a sloppy, lopsided storm due to dry air and shear, most of the impacts should be confined to the north and east quadrants.

Summary

  • Odds of tropical or subtropical cyclone forming in the western Gulf by Thursday or Friday continue to rise.
  • While a track toward the north-central or northeast Gulf Coast is likely, dry air and wind shear should keep a lid on intensification.
  • There will be impacts along the northern Gulf Coast, but placement can’t yet be pinned down due to uncertainty regarding track, which will be fine tuned over the next day or two.
Caleb Carmichael
Caleb Carmichael

Caleb is the owner of Gulf Coast Storm Center. He is currently an undergraduate student at Mississippi State University majoring in geoscience with a concentration in broadcast and operational meteorology. While not yet a meteorologist, Caleb has been providing weather updates, news, and analysis for the Gulf Coast since 2014.

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