Gulf of Mexico oil spill slows its advance towards the coast

The oil slick from the April 20 explosion and blowout of the offshore oil rig Deepwater Horizon continues to affect the Louisiana coast near the mouth of the Mississippi River, and along the Chandelier Islands off the coast of Mississippi. Strong south to southeast winds blowing at 15 - 25 knots will continue through Monday, which will push oil onto portions of the eastern Louisiana coast from the mouth of the Mississippi River northwards towards the Mississippi border. However, the current trajectory forecasts now show the advance of the oil will slow over the next few days, despite the strong onshore winds. This is probably due to the fact that the shape of the Louisiana coast is setting up a counter-clockwise rotating eddy over the ocean regions between the Mississippi coast and the mouth of the Mississippi River, as seen on the latest forecast of Gulf currents from the NOAA HYCOM model (see also this alternative view of the HYCOM ocean current forecast.) Unfortunately, there are no buoys in this region of the Gulf to tell us what the currents are.


Figure 1. The oil spill on May 1, 2010, as seen by the MODIS instrument on NASA's Terra spacecraft. Image credit: NASA.

It now appears that the Mississippi, Alabama, and Florida Panhandle coasts will not see significant amounts of oil hitting their shores through at least Monday. On Monday night, the winds shift to southwesterly and weaken as a cold front approaches. The wind shift will allow oil to move eastwards towards Alabama and the Florida Panhandle, but at just 1 mph or so. The winds with then shift to offshore (northwesterly) on Tuesday as the cold front passes. This should blow the oil back out to sea a few miles. It is thus possible that only the Louisiana coast will see oil impacts over the coming seven days, though there is substantial uncertainty in this forecast. High pressure is expected to build in late next week, bringing relatively light onshore winds that should allow for slow transport of the oil towards shore. It appears very unlikely that oil will make it into the Loop Current during the next seven days and affect the southern Gulf of Mexico. The long range wind forecast beyond that time is too uncertain to say what might happen at longer time ranges.


Figure 2. Previous location and forecast location for today of the Deepwater Horizon oil spill. Image credit: NOAA Office of Response and Restoration.


Figure 3. Trajectory forecast for the Gulf of Mexico oil spill for 6 pm CDT Monday May 3, 2010. Image credit: State of Louisiana.

High risk of severe weather tonight
NOAA's Storm Prediction Center has outlined a "High Risk" region of severe weather potential over Arkansas tonight, and there are numerous tornadoes currently being reported over Arkansas. Our severe weather expert, Dr. Rob Carver, has radar images of yesterday's strongest storms in his blog today, including images of the tornado north of Little Rock that killed one person and injured several dozen.

Jeff Masters