Thunderstorm asthma alerts issued for southern NSW and Canberra as rainy weather sweeps in

Thunderstorm asthma alerts have been issued for the Australian Capital Territory and New South Wales’s nearby Murrumbidgee region this weekend.

The Bureau of Meteorology said a low-pressure trough and strong cold front would continue to cross NSW on Sunday, reaching the north-east of the state by evening and leaving significantly cooler conditions in its wake.

A new high-pressure system was forecast to strengthen south of Tasmania early this week, with the potential to maintain showery conditions across eastern areas for a number of days.

Health authorities warned that severe thunderstorms, combined with existing elevated pollen levels, could create a situation conducive to a thunderstorm asthma event.

“Not all thunderstorms produce an asthma event, and thunderstorm asthma is a rare event,” ACT Health said in a statement.

Related: Thunderstorm asthma: 'You're talking an event equivalent to a terrorist attack'

“However, people who suffer from hay fever or asthma are encouraged to be vigilant over the weekend for any worsening of their condition. Where possible avoid being outside during a thunderstorm – especially in the wind gusts that come before the storm. Go inside and close your doors and windows. If you have your air conditioning on, turn it on to recirculate.”

The NSW public health unit director, Tracey Oakman, issued a thunderstorm asthma alert for the Murrumbidgee local health district area for the entire weekend.

“If you know you have asthma, carry your asthma puffer with you at all times and try to stay indoors with the windows and doors closed during the storm period,” the NSW Health statement said.

“Be aware that thunderstorm asthma can also affect people who have not had asthma before.”

Ten deaths were attributed to a thunderstorm asthma event in Melbourne in November 2016 and 14,000 people were taken to hospital with breathing difficulties.

A sheep graziers’ warning was also in force for the NSW south coast, southern tablelands, Snowy Mountains and parts of the Illawarra, south-west slopes, Riverina and Australian Capital Territory. And in Victoria, the north-central, south-west and central districts and parts of the west and South Gippsland and East Gippsland areas were subject to the same warning. The BoM said cold temperatures, showers and strong winds could cause losses of sheep and lambs on Sunday.

A gale warning was in force for the Hunter and Sydney coastal areas on Sunday and a minor flood warning was in place for the Murray River around Jingellic. In Victoria there were also flood warnings for the Bunyip and Kiewa rivers and Dandenong Creek.