Hurricane Helene and the 'Fujiwhara Effect': Will it impact Chicago?

CHICAGO - Hurricane season is at its peak, and the latest storm grabbing attention is Hurricane Helene.

Helene will make landfall in the Big Bend of Florida on Thursday night as a major hurricane. Catastrophic impacts are expected as Helene makes landfall. Life-threatening storm surge will likely exceed 12 feet along the coastline of the Big Bend region.

Following landfall in Florida, Helene will move northward into Georgia. This is where the forecast takes an interesting turn. A rare weather phenomenon will occur as Helene interacts with another system that is sitting over the south-central United States.

These two systems will undergo what we call the "Fujiwhara Effect." The National Weather Service defines the Fujiwhara Effect as "a binary interaction where tropical cyclones within a certain distance of each other begin to rotate about a common midpoint."

While Helene won’t be interacting with another tropical cyclone, it will begin a dance with the other low pressure system around a common center. Both systems will be impacted by the other, and in the case of Hurricane Helene, the two will merge into one storm over the south-central US.

This interaction will steer Helene to the northwest, allowing the remnants to impact Chicagoland.

Friday will become very windy with northeast wind gusts over 40 mph in the afternoon and evening. The National Weather Service has issued a Wind Advisory for Kankakee, Newton, and Jasper Counties from 1 p.m. Friday through 12 a.m. Saturday. Wind gusts within the advisory area could exceed 45 mph. Scattered power outages will be possible on Friday afternoon and evening.

The remnants of Helene will still be in the region this weekend, likely bringing rounds of scattered rain to Chicagoland on Saturday and Sunday.