Storm formation in the Caribbean could become Hermine, enter the Gulf of Mexico

After a quiet start to the hurricane season, the Atlantic has awakened and is full of storms and systems to watch, and at least one could pose a serious threat to the United States.

There is great concern over a downpour in the north of Venezuela nicknamed “Invest 98L”, which has crossed the windward islands with gusts of wind and gusts of rain. That will stay tame until the weekend, when it’s ready to move into a powder keg atmospheric environment.

It could enter the Gulf of Mexico next week, although its exact track is still uncertain. Assuming she grows up in at least a tropical storm, she’ll be called Hermine. The National Hurricane Center offers a 90 percent chance of doing so.

For now, anyone residing along the Gulf Coast and Florida should pay close attention to this as forecasts will evolve in the coming days.

Fiona will lash parts of Canada as the strongest storm ever recorded in the region

At the moment, it is poorly organized. The reason it isn’t doing much yet is because of the disruptive cut or a change in wind speed and / or direction with height, which it is fighting. Too many shear forces can send a fledgling storm haywire, as if it were being subjected to an atmospheric tug-of-war game. That cut is the mood of Fiona’s high altitude runoff, or drain, far north-east.

Hurricane Fiona struck Puerto Rico on Sept. 18, leaving residents without light, water, and safe shelter. Residents of Ponce and Salinas shared their stories. (Video: Zoeann Murphy, John Farrell, Drea Cornejo / The Washington Post)

Invest 98L will move west over the next few days, being hampered by the cut until Sunday. Things will escalate a lot quickly from Sunday evening to Monday.

This is when the cut will relax as the 98L moves over some of the warmest waters in the Atlantic. The Northwest Caribbean is filled with ocean heat, or thermal energy contained in bath-like marine waters, which will support accelerated consolidation and strengthening of the nascent storm.

Simultaneously, 98L – at that point likely a named storm – will move under a higher-level high-pressure system. This will work in favor of 98L in two ways:

  • divergence. High pressure means separate air diffusion. That divergence in the upper atmosphere will have a vacuum-like effect, creating a vacuum and making it easier for surface air to rise. This improvement in thunderstorm updrafts will accelerate the rate at which hot, humid “rush” can precipitate into the storm.
  • Outflow. Treble turns clockwise. This is the direction of the outflow of the tropical cyclone in the Northern Hemisphere. That high pressure will work with 98L to evacuate high-flying “exhausted” air away from the storm, allowing it to ingest more compressed air from below. Imagine placing an intake fan on top of a chimney. The air would be pulled up and out, which means more air would rush in from below and the fire at the base would increase. This storm will do the same.

The potential exists for a very strong storm to be located somewhere in the northwestern Caribbean on Monday. At that point it could escalate rapidly.

However, it could trace anywhere from Mexico’s Yucat√°n Peninsula to central Cuba. But the storm could also creep between those regions, entering the Gulf of Mexico towards the end of Monday or Tuesday.

There are only two escape routes that could allow the storm to avoid the gulf. There is an external possibility that, if it remains weak, it can continue westward in the Caribbean to Central America. If it gets stronger quickly, it could turn north over central Cuba and lean towards the Atlantic. But only a minority of model simulations exhibit these anomalous scenarios.

Watch Hurricane Fiona surf footage from the top of a 50-foot wave

Most model simulations predict that the system will end up in the gulf, while subtleties in atmospheric steering currents will determine where the storm will eventually come ashore.

One little piece of good news is that if the storm lands in the northern or western Gulf of Mexico, the dry air is coming from the north it may weaken it slightly. It’s not very comforting, however, when virtually the entire Gulf region is warmer than average during the busiest time of year for hurricanes.

If the storm blows further east, it could escape such dry air. It would be a concern if any potential trail brings it closer to Florida.

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