A series of troughs moving on and off shore are poised to produce the most significant rain event of the summer across Queensland and eastern New South Wales this week.

An upper trough system combined with a moist easterly flow and two slow moving surface troughs, one offshore, are behind the forecasts of widespread rain and thunderstorms.

Chief meteorologist with the Weather Channel Dick Whitaker said the major rain event was expected to produce widespread seven-day totals in excess of 200 mm over southeast Queensland and northeast New South Wales and totals of 100 mm plus over inland parts of Queensland.

An equatorial trough has moved south over the past week, increasing the potential for tropical cyclone development over the next seven days.

Mr Whitaker said a cyclone was likely to form over the Indian Ocean side of the mainland during the week, and if this happens it will be called “Iggy”.

There was also a moderate chance of tropical cyclone development off the Arnhem Coast of the Northern Territory later in the week and a flood threat advice has been issued for the Darwin Daly and Arnhem districts.

Northerly winds were expected to generate high temperatures across South Australia and Victoria over the next two days, with Adelaide in particular expecting temperatures of 37 degrees Celcius today and tomorrow. Melbourne can expect tops of 34 degrees on these days.

Mr Whitaker said hot easterly winds were set to produce high temperatures across Perth across the week, with temperatures above 35 degrees for the next seven days.

The average top temperature for the Perth Regional Office is 29.7 degress for January, so the predicted tops for the next seven-days would constitute a heat wave under the 5/5 rule (five consecutive days of maximum temperatures reaching 5 degrees or more above the average).