This week, there will be active weather in northern Australia and the Mascarene Islands in the south Indian Ocean. The monsoon trough will play a role in both of these events.

The monsoon trough refers to a section of the Intertropical Convergence Zone that has an impact on the overall monsoon circulation. This section is characterized by a decrease in sea level pressure and an increase in vorticity, which measures the rotation of the atmosphere.

On Thursday, January 11th, a region of unsettled weather formed along the monsoon trough to the east of northern Madagascar. The disturbance moved towards the southwest and rapidly organized, reaching tropical cyclone status by Friday and becoming a severe tropical storm by Saturday.

The cyclone Belal experienced optimal atmospheric and oceanic conditions on Saturday, leading to a rapid increase in wind speeds of 30 knots within 24 hours. It is predicted to reach the island of Réunion on Monday afternoon. Météo-France has issued a red warning for the island, as the last time Réunion faced such a danger was in January 1989 with Cyclone Firinga.

It is anticipated that Belal will maintain its strength as a storm throughout the upcoming week. It will move south of Mauritius on Tuesday and then continue eastward towards Rodrigues later in the week.

In other areas, the monsoon trough is predicted to stretch over the northern region of Australia in the coming week, causing a flow of moist air from the north-west. Although the Australian monsoon is usually weakened during an El Niño event (due to the concentration of rain shifting eastwards with the movement of warmer waters), there is expected to be heightened activity in the monsoon this week.

From Monday to Saturday, a large area in the northern half of the Northern Territory and northern Queensland is forecasted to experience intense thunderstorms that could result in over 100mm of rainfall. The Northern Territory is anticipated to be hit the hardest, with a potential of 300mm of rain locally, which is significantly higher than the usual January precipitation. In the following week, there is a possibility that the heavy rain will spread southwards and impact the southern regions of the Northern Territory.

Source: theguardian.com