A lone seagull watching the sun rise over North Cronulla beach.

A lone seagull watching the sun rise over North Cronulla beach. Photo: John Veage

Sydney faces the chance of more thunderstorms on Friday and over the weekend as the city’s run of record warm weather heads towards a third week.

Parts of the western suburbs and the Blue Mountains are likely to see thunderstorm activity from late morning until tonight with eastern areas likely to be spared. There is a small chance of a shower moving over ANZ Stadium for the Wests Tigers v Rabbitohs game tonight.

For Saturday, afternoon sporting and other outdoor activity may be disrupted, particularly in the west with more storms expected and showers likely over the rest of the city, said Ben Domensino, senior meteorologist with Weatherzone.

Chris Van Krevel takes an early morning dip on the Illawarra coast.

Chris Van Krevel takes an early morning dip in a pool on the Illawarra coast. Photo: Kirk Gilmour

"We’ve got this instability just lingering around," Mr Domensino said, adding the city was unlikely to get a repeat of recent severe storm fronts moving in as happened last Saturday.

Unusually warm weather is contributing to the "pretty good set-up for thunderstorms", conditions that are likely to prevail well into next week, Mr Domensino said.

Friday’s temperatures recently topped 26 degrees, making it the 19th consecutive day above 25 degrees and extending the record well beyond the previous tally of 16 such days in 1977.

A line of storms moves into Sydney on March 15.

A line of storms moves into Sydney this week. Photo: Nick Moir

The revised forecast by the Bureau of Meteorology is for at least 25 degrees each day until Monday, indicating the record series may extend to at least 21 days.

Large blocking high-pressure systems in the Tasman have been key to keeping cooler conditions much further south than usual.

"At this time of year, you’d typically start to see cold fronts becoming a bit more prominent," Mr Domensino said.

Weatherzone: Sydney radar




So far this month, the average maximum is running at 26.9 degrees, not far below the record of 27.1 degrees set in 2006, he said. March 2006 had its first 13 days reach at least 26 degrees - a record stretch that been eclipsed this year with 17 such days up including today, Weatherzone said.

Along with the warm weather, though, drier-than-usual conditions have generally prevailed. A record of almost 80 per cent of Queensland has been declared in drought and much of northern NSW remains in severe rainfall deficit conditions.

Next week should bring some relief, with widespread falls predicted for much of inland NSW and southern Queensland at least.

Many areas will get 20-50 millimetres of rain but some parts of northern-eastern NSW may get as much as 100 millimetres, Mr Domensino said.

El Nino risks rise

Longer term, though, the outlook continues to tilt towards dry conditions lingering as the chances of an El Nino weather pattern forming in the tropical Pacific increase.

El Ninos, which are marked by a warming over the eastern equatorial Pacific, typically result in rainfall shifting eastwards. That means eastern Australia could see the current dry conditions intensify.

Overnight, a US forecaster MDA Weather Services estimated that an El Nino is now a 75 per cent prospect of forming during the coming southern winter, Bloomberg News reported.

This month, Australia’s Bureau of Meteorology reported Pacific Ocean temperatures were likely to approach or exceed El Nino thresholds during this winter.

"It is pretty safe to say a number of climate models are pointing towards an El Nino event [forming] this winter into spring," Mr Domensino said.

Weatherzone.com.au is owned by Fairfax Media, publisher of this website.