Track changes aloft over the US Gulf

General overview 1500Z 3rd July 2013

As we discussed yesterday, conditions aloft over the Gulf of Mexico are unusually chaotic with three dominant systems vying for position. Disturbances two and twelve are approaching from the south into the Gulf of Mexico and an upper level trough is running almost the length of the Gulf coast and out into the Atlantic. When conditions are as unsettled as this, forecasts become unreliable and systems tracks can change overnight.

Disturbance ten is now in the eastern Bay of Campeche and moving west at walking pace but now looks set to accelerate and turn to the north-nor'west later in the week. Upper level shear is still preventing development however it is possible that as the frontal system currently in place over southern Texas shifts east, a slight opportunity for development may open up in its wake. In this case, there is a chance for this to become a tropical depression or weak tropical storm before moving inland into Texas or Louisiana on Sunday. Regardless of development, squally conditions are likely over the Bay of Campeche today and tomorrow, and the northwest Gulf by the weekend.

Disturbance twelve is near western Cuba and racing north-nor'west at 15 knots to merge with the upper level trough along the Gulf coast. This won't develop but will add to the generally mucky conditions with bands of heavy rain, thunderstorms and gusts of strong winds over the eastern Gulf of Mexico within the next 24 hours before grounding in the Mississippi/ Alabama area and then disappearing into the dominant trough.

Disturbance thirteen is now mid-Atlantic and starting to lose the benefit of the convergence zone as it drifts north and now looks as if it might lose interest altogether before it reaches the western half of the Atlantic basin.

Disturbance fourteen is an interesting system which has the modellers salivating. This is an upper-level cell of low pressure in mid-Atlantic, which is orbiting a high pressure area and shaping up to spin off and track back towards the continental United States. This could reach southern Florida in about 5 days' time and may even moving west into the Gulf of Mexico. This is a curved ball and warrants watching closely.

A new low pressure cell looks set to slip the surly bonds of the African coast in the next day or so. Happy days.

Stand easy