Severe weather in NSW could cause Hawkesbury-Nepean River flooding and bring intense rainfall to a region extending from the state’s south to north of Sydney, the Bureau of Meteorology has warned.

Meteorologist Angus Hines says rainfall totals in some areas may be “well and truly” into the 200mm range over the next few days, and inland Sydney and Illawarra regions could receive up to 300mm.

“The primary threat here is heavy to locally intense rainfall with thunderstorms, but don’t rule out the chance of some damaging wind,” Mr Hines said today. “Flash flooding and riverine flooding are both possible. This is going to be a dynamic and serious situation.”

Parts of southern Queensland and northern NSW have already been receiving heavy falls, but the focus will shift tomorrow to the NSW coast and around the mountains. The bureau has issued a severe weather warning for a broad region, as a coastal trough amplifies the rainfall.

Minor to major flooding is possible in the Hawkesbury-Nepean River from late tomorrow, while minor to moderate flooding is possible across parts of the NSW coast from late today.

Sydney is forecast to receive 50-100mm of rain tomorrow, while Richmond to the city’s west may receive 35-130mm. Wollongong may also receive 35-130mm, the bureau forecast this afternoon.

Catchments are relatively wet in the north of the state and average to dry around Sydney and the South Coast.