As well, an upper level ridge forms over the South Pacific Ocean along with an upper level trough extending from subtropical latitudes to the South Atlantic Ocean.
12.
Over the next few days the system was steered towards the southeast by a north-westerly steering flow on the eastern side of an upper level trough of low pressure.
13.
Widely scattered to locally scattered light showers are expected across the area tonight and monday morning before a strong upper level trough approaches puerto rico from the west monday afternoon.
14.
Due to a combination of an upper level trough that moved southward over the Baja California Peninsula and the weakening of the ridge, the hurricane began to turn more northwestward.
15.
On October 10, Norbert turned towards the north while slowing down as it reached the western edge of a mid to upper level trough that was moving over the Southwest United States.
16.
After being named, Fergus performed a cyclonic loop in an area of weak steering flow, before it started to move south-eastwards, under the influence of an approaching upper level trough of low pressure.
17.
The system subsequently started to move towards the southeast during December 29, in response to a strengthening steering flow, provided by an upper level trough of low pressure and a baroclinic system near New Caledonia.
18.
The system was subsequently steered south-eastwards by an upper level trough of low pressure, before it made landfall as a Category 2 tropical cyclone on the Cape York Peninsula near Cape Keerweer during December 25.
19.
Over the next day atmospheric convection developed and organised over the systems low level circulation, as it moved southeastwards away from the Queensland Coast under the influence of an upper level trough of low pressure.
20.
Zoe subsequently turned towards the southwest and passed in between the Solomon Islands of Anuta and Fataka, as the subtropical ridge weakened in response to an upper level trough of low pressure over the Tasman Sea.
