100 mph wind gusts? Francine could get that strong, hurricane forecasters say.

Editor's note: Read Tuesday's updates on Francine as the storm takes aim at the U.S. Gulf Coast.

Tropical Storm Francine – soon to be Hurricane Francine – has been slowly gathering strength since it formed Monday in the Gulf of Mexico, with winds now estimated at 65 mph as of Tuesday morning. One question is: How strong will Francine get before it hits land?

"Steady to rapid strengthening" is forecast before Francine approaches landfall Wednesday evening in Louisiana, the National Hurricane Center said. However, the forecast has decreased slightly and now calls for sustained winds of 90-95 mph near the storm center. This would make it a Category 1 hurricane on the Saffir-Simpson Scale of Hurricane Intensity.

Thanks in part to unusually warm seawater in the Gulf of Mexico, Francine could even undergo what meteorologists call "rapid intensification," which occurs when a storm increases its wind speed by at least 35 mph within 24 hours.

The National Hurricane Center's new experimental cone graphic shows both coastal and inland watches and warnings along Tropical Storm Francine's forecast path.
The National Hurricane Center's new experimental cone graphic shows both coastal and inland watches and warnings along Tropical Storm Francine's forecast path.

Warm water vs. wind shear

However, while there's plenty of warm water for intensification, strong winds aloft could prevent strengthening:

"The tropical cyclone should be over very warm waters before landfall, although west-southwesterly vertical wind shear over the system is likely to increase," the hurricane center said in an online forecast released Tuesday morning. "The latter environmental influence will probably limit Francine's strengthening."

Wind shear acts to rip apart tropical cyclones, preventing them from forming and strengthening.

Tropical Storm Francine in a color-enhanced composite satellite photo on the morning of Sept. 10, 2024.
Tropical Storm Francine in a color-enhanced composite satellite photo on the morning of Sept. 10, 2024.

When and where will Francine's winds be worst?

"Damaging and life-threatening hurricane-force winds are expected in portions of southern Louisiana Wednesday, where a Hurricane Warning is in effect," the hurricane center said. Gusts of up to 115 mph are possible.

As of Tuesday morning, the greatest probability of high winds is in Louisiana's St. Mary, Iberia, Terrebonne and Cameron parishes. Each parish has a more than 5% chance of experiencing winds greater than 74 mph, and a greater than 80% chance of experiencing tropical storm force winds, according to the hurricane center.

Preparations to protect life and property should be complete by tonight, since tropical storm conditions are expected to begin within this area early Wednesday, the center said.

What kind of damage could Francine cause?

Although a Category 1 is forecast at landfall, the hurricane center advises people in the path of the storm to plan for one category higher. According to the hurricane center, extremely dangerous winds would cause extensive damage during a Category 2 storm. This includes:

  • Well-constructed frame homes could sustain major roof and siding damage.

  • Many shallowly rooted trees will be snapped or uprooted and block numerous roads.

  • Near-total power loss is expected with outages that could last from several days to weeks.

What to know about rapid intensification

Warmer sea surface temperatures may contribute to an increased fraction of tropical cyclones that undergo rapid intensification, Climate Central said Tuesday.

From 1980 to 2023, 177 landfalling Atlantic tropical cyclones rapidly intensified, Climate Central said. Roughly 70% of the 63 billion-dollar tropical cyclones in the U.S. since 1980 rapidly intensified.

It happened with Idalia last year and Hurricane Ian experienced two periods of rapid intensification in 2022.

Sea surface temperatures are warm across the Gulf of Mexico and Caribbean, and warm water provide storms with more energy and moisture.
Sea surface temperatures are warm across the Gulf of Mexico and Caribbean, and warm water provide storms with more energy and moisture.

Tropical Storm Francine tracker

Francine spaghetti models

Spaghetti model illustrations include an array of forecast tools and models, and not all are created equal. The Hurricane Center uses only the top four or five highest performing models to help make its forecasts.

This article originally appeared on USA TODAY: Will Francine rapidly intensify? Category 1 hurricane in forecast.