We’ve been watching an area of disturbed weather, dubbed Invest 92L, the past few days as its chances for tropical development rise now to 90% within both the next 48 hours and 5 days. This is associated with a disturbance that began in the Plains and is now moving south of the Tennessee River Valley, taking an unusual path to the northeastern Gulf of Mexico.
Now that the thunderstorms that Invest 92L is producing are moving over the Gulf of Mexico, tropical development will likely begin to take place. There are several ingredients required for a tropical cyclone to form. That includes very warm sea surface temperatures of at least 80°F and low wind shear. These warm ocean temperatures are guaranteed since they are already present, and it takes an extended amount of time for the temperature to drop or rise.
Now in terms of wind shear, forecasts show weak shear for the most part while Invest 92L is over the northern Gulf of Mexico. With that said, we agree with the National Hurricane Center for 92L’s bullish formation predictions. The only component missing that prevents Invest 92L from becoming either a tropical depression or storm is the lack of a closed, low level circulation, or confined low pressure center. The ingredients mentioned above, however, should help a center form by late-week, allowing for 92L to likely become Tropical Storm Barry.
According to the National Hurricane Center, “Environmental conditions are expected to be conducive for tropical cyclone formation and development over the next several days, and a tropical depression is likely to form by late Wednesday or Thursday while the system moves westward across the northern Gulf of Mexico.” They have also stated how aircraft reconnaissance missions, or the Hurricane Hunters, may fly into this tropical entity as early as Wednesday to collect crucial data that may help better its forecasts and determine if the system is a tropical cyclone yet.
Impacts are already beginning from Invest 92L with rounds of showers and thunderstorms rolling into the northern Gulf Coast. Some of these storms will be heavy, dumping over an inch of rain. The rip current risk will also be elevated, but it’s not until Friday or Saturday when more-direct impacts may begin across parts of the Gulf Coast region. That’s because what will likely become Barry will begin to move onshore between southeastern Texas and Mississippi. We don’t know how strong this entity will be. It may not even be a tropical cyclone after all, but the best chance as of now is that parts of the region will be dealing with Tropical Storm Barry. There is even the outside chance it will become a hurricane thanks to the very warm sea surface temperatures, especially near southeastern Louisiana, and some of the models are suggesting this evolution.
When this tropical entity does begin to move onshore late-week into this weekend, the main impacts will be heavy, flooding rains, strong, damaging winds, rough surf, and rip currents. We are especially concerned about the rain. This is a threat often downplayed with tropical storms, but this will be the most serious risk based on the forecast rainfall totals and the current environment. Some of the model guidance is projecting over 2 feet of rain for some areas on top of the already saturated ground. If this rain were to fall in the Mississippi River Valley, that would be bad news. That’s because water levels are very high, so any extra rainfall will make the situation even worse.
High winds will also be a concern, causing downed trees and power outages. Both the winds and rainfall are still uncertain, however, because we do not know what the intensity of this storm will be yet. We also don’t know the track, which will determine where these heavier rainfall totals and strong winds end up. Within the next couple days, we should have a better idea of what will happen.
We’ll have another update by Thursday on Invest 92L. Until then, follow us on Twitter @WeatherOptics for continuous updates.