Ag Weather Forum

As an update to the story posted Monday, https://www.dtnpf.com/…, the tropical disturbance that was in the northwestern Caribbean on Monday became Tropical Storm Helene on Tuesday and has continued to rapidly strengthen into a hurricane early on Wednesday as it moves into the Gulf of Mexico.

The center to the hurricane is about 40 miles northeast of Cancun, Mexico, with maximum sustained winds of 80 mph. Rain bands from the hurricane have started to show up over western Cuba on the Key West, Florida, radar station, a sign of the imminent threat of the storm.

Warm waters in the Gulf should cause the storm to rapidly strengthen throughout the day Wednesday, becoming a major hurricane on Thursday with maximum sustained winds of at least 111 mph as a Category 3 storm. Forecasts have the storm making landfall in the Big Bend area of Florida east of Apalachicola Thursday evening, then heading north through western Georgia and eastern Tennessee, rapidly weakening into a remnant low early Friday. Typically, after landfall hurricanes are pushed eastward by the prevailing upper-level winds. This one is different, though. In an interesting twist and rare occurrence, the remnant low will get pulled westward toward the Ohio River during the day and possibly park in western Kentucky for Saturday as the low gets wrapped up with an upper-level low in that area. The two lows will sit in the Tennessee Valley the rest of the weekend before getting pushed eastward early next week.

Heavy rain will fall across Florida, Georgia, and the southern half of the Appalachians and forecasts calling for 5 to 10 inches seem very plausible. Rainfall closer to the Ohio Valley is forecast to be more in the 2- to 4-inch range, though pockets of heavier rain may occur. The rain would be good for the region as building drought has taken a toll on late-developing crops and water levels on local rivers, including the Mississippi, which again has fallen to near record lows at Memphis. However, it is coming at a very bad time for harvest. Much of the cotton has opened its bolls, but little of it has been harvested as of Sept. 22, according to USDA. The hurricane could have devastating impacts for corn and soybeans as well, as states along the Ohio River have less than half of their crops harvested so far.

What has been amazing about this storm is how consistent the modeled forecasts have been. Two days ago, the track and development were basically the same as the current track and development. The landfall may have shifted eastward less than 50 miles. Typically, these forecasts change and especially with regard to the interaction with an upper-level low. The questions about the rainfall potential for the Ohio Valley have been consistent and well-captured by models so far, though they have tightened the risk area of the heaviest rain. If there has been any significant change with the system, it has been that the lows -- the upper-level low and the remnant hurricane -- are more likely to be pushed eastward early next week instead of the middle of next week. Otherwise, the forecasts have been remarkably similar over the last few days.

To find more weather conditions and your local forecast from DTN, head over to https://www.dtnpf.com/…

John Baranick can be reached at john.baranick@dtn.com

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