Hurricane Isaias is forecast to strengthen from Category 1 to Category 3, with winds up to 100 mph, before making landfall Friday around 2 p.m., according to a FreightWaves Sonar analysis. The projected path stretches from just east of Houston to the Florida Panhandle, putting major freight corridors and Gulf Coast energy infrastructure directly in harm's way.

The most consequential supply chain risk sits in the energy sector. Up to six refineries lie in the storm's path, and Gulf State refineries collectively account for 50% of the nation's refining capacity — a total of 18.2 million barrels per day. Offshore production operators have already sent home nonessential workers, though output continues normally for now. Any significant damage could take days to weeks to repair, a concern amplified by already-elevated diesel prices.

"Gulf State refineries account for 50% of the national refining capacity of 18.2 million barrels per day. I don't think this storm is going to be strong enough to do a lot of damage — but it is something for us to keep watching as we're already in this current environment where diesel prices are incredibly elevated," said Julie Van de Kamp.

How are freight markets already reacting?

Southeast markets are moving before the storm arrives. Tender rejections in New Orleans, Mobile, and Montgomery are running in the 17% to 19% range, edging above national averages. Truckload volumes are also ticking upward in New Orleans and Mobile as some shippers move freight ahead of landfall.

Van de Kamp expects a "Southeast pop" in spot rates and tender rejections, with the magnitude depending on the extent of flooding and how quickly carriers can access affected areas once the storm passes. For shippers with Gulf Coast exposure, that translates into tighter capacity and higher spot costs in the immediate aftermath, while carriers positioned to re-enter flooded markets quickly could capture surge demand.

What happens to ports and emergency freight?

Port operations are another watch item. The Port of Mobile and the Port of New Orleans both fall within the projected impact zone, raising the possibility of vessel delays and slowdowns in cargo unloading. Van de Kamp said the Port of Houston is not expected to be significantly affected.

FEMA staging locations — including Jacksonville and Atlanta — could also generate emergency freight demand in the days following landfall, adding a burst of truckload volume outside the directly affected zones. Forwarders and brokers should watch those inland markets for tightening capacity even where the storm itself causes little damage.

How severe will the flooding be?

Rainfall totals of 3 to 6 inches are expected across a broad swath of the region, with localized amounts potentially reaching 10 inches. Malcolm Harris, who provided the meteorological analysis, said flooding is his primary concern, noting that the storm's eye is becoming more defined by the hour. He advised residents in Gulf Shores, Alabama, and the Baton Rouge area to monitor conditions closely and use common sense regarding evacuation decisions.

"I do not play about the weather," Harris said, adding that areas from Louisiana to the Florida Panhandle should prepare for torrential rain, wind, and storm surge.

For freight operators, the practical risks break down into three buckets:

• Energy: refinery outages or curtailments pushing diesel prices higher from already-elevated levels
• Trucking: spot rate spikes and tender rejection surges across New Orleans, Mobile, and Montgomery
• Ports and emergency flows: vessel delays at Mobile and New Orleans, plus FEMA-driven demand from Jacksonville and Atlanta staging sites

FreightWaves will continue monitoring Sonar's WeatherOptics and Everstream tools for shifts in tender rejection rates and freight volumes as Isaias approaches the Gulf Coast, with the Friday afternoon landfall the key checkpoint for whether the projected Southeast pop in rates materializes.