Cristobal is expected to strengthen before making landfall late on Sunday on the Louisiana coast but is unlikely to reach hurricane strength according to the US National Hurricane Centre (NHC).
The agency warns of a life-threatening storm surge, and tropical storm force winds are expected by late Saturday from central Louisiana, including New Orleans, to the western part of the Florida panhandle.
Grand Isle, a barrier island on the Louisiana coast, is under a mandatory evacuation order, ahead of the surge expected to be between two and four feet in an area from Morgan City, Louisiana to the mouth of the Mississippi River.
Between four and eight inches of rain could fall, according to the NHC forecast, contributing to significant flooding.
While offshore oil facilities were evacuated, the nine Louisiana oil refineries in the path of Cristobal, operated by Exxon Mobil, Royal Dutch Shell and PBF Energy, plan to keep operating, Reuters reported. They account for 12 per cent of total US refinery capacity.
Flooding will be a significant threat from Tropical Storm #Cristobal. Widespread areas of 3-5" of rain is possible. Locally, some areas could see over a half a foot of rain. pic.twitter.com/aXGhHYTBvj
— The Weather Channel (@weatherchannel)
On Saturday afternoon, the storm was approximately 310 miles south of the mouth of the Mississippi River and travelling north at about 12mph, according to the NHC.
The NHC predicts a particularly busy hurricane season for 2020, with 12-19 named storms, six to ten hurricanes, and three to six major hurricanes.
— Stu Ostro (@StuOstro)
With reporting from Reuters