A broad area of severe thunderstorms will affect three states in eastern Australia on Monday, with damaging winds one of the main threats with these fast-moving storms.

The interaction between a cold air mass moving up from the south and a warm, humid air mass drifting down from the north will create ideal conditions for intense thunderstorms in eastern Australia on Monday.

A few storms were already occurring in the morning around Lightning Ridge and Queensland's Maranoa and Warrego District. As the day progresses and the air near the ground gets warmer, thunderstorms will become more widespread and intense over eastern Australia.

Image: Composite satellite/radar/lightning image from 9am AEST on Monday, showing thunderstorms over northern NSW and southern Queensland.

Showers and thunderstorms are likely to develop in central and eastern Victoria, parts of western, central and eastern NSW (including the ACT) and in southern and western Queensland. Some thunderstorm activity will also extend into central and northern areas of the NT. Altogether, Monday's thunderstorms will extend over 3000 kilometres from Victoria up to the Top End.

Image: Thunderstorm outlook for early Monday morning. Access these storm outlook maps on Weatherzone Layers.

Some of these thunderstorms are going to become severe, with damaging to locally destructive wind gusts the main threat. Heavy rain and large hail are also possible, although generally less likely than dangerous winds because the storms will be fast-moving.

A cold front and associated trough will pick up humid air left by the previous system today, producing thunderstorms from eastern VIC to the Top End. pic.twitter.com/ephkcfpIyT

— Andrew Miskelly (@andrewmiskelly) September 20, 2020

Melbourne has a risk of showers and thunderstorms on Monday morning up until about midday. Canberra has a good chance of showers or thunderstorms during the afternoon and early evening. Sydney will be warm and dry during the day, although dangerous storms could pass over the city from the west in the late afternoon and early evening.

Warnings will be issued and updated throughout Monday as thunderstorms develop, so be sure to check the latest information for your area.