THE Bureau of Meteorology (BOM) has issued a severe weather warning for parts of NSW today (August 4), with heavy rainfall and wind gusts of up to 90km/h possible over ranges to the west of the ACT.

According to the BOM, a complex low pressure system moving across the Great Australian Bight and an associated trough and cold front are causing vigorous northwesterly winds across southeast NSW. The front will move offshore early Friday morning.

Damaging wind gusts possible over the ranges to the west of Canberra, as well as the eastern Great Dividing Range from Bombala to south of Crookwell, extending north to the Blue Mountains during Thursday morning.

Minor flood warnings have been issued along the Queanbeyan and Molonglo Rivers as the BOM predicts up to 100mm of rainfall in the area over the coming days.

Damaging winds, averaging 80 to 90 km/h with peak gusts in excess of 125 km/h are likely to continue for alpine areas above 1900m.

Heavy rainfall which may lead to flash flooding is expected across the Snowy Mountains and the South Western Slopes. Six-hourly rainfall totals between 45 and 60 mm are expected, with localised falls up to 100 mm possible with embedded shower and thunderstorm activity that may occur over shorter time frames.

A flood watch has been issued for Braidwood, Goulburn, Bombala, Tumbarumba, Tumut, Khancoban and Thredbo Top Station.

Severe weather warning for southeast NSW