Widespread showers and thunderstorms reached a peak this afternoon after kicking off in the early hours of this morning. A large cut-off low and associated trough is slowly making its way across the Great Australian Bight triggering showers and thunderstorms over South Australia. Isolated thunderstorms began firing before the sun had even risen this morning over southwestern parts of SA. As the day progressed, thunderstorms began to fire up as a deep low pressure trough and upper level cold pool worked in conjunction to provide optimum conditions for instability. In the period from 3am this morning until 4pm CST, over 4,693 lightning strikes were recorded within a 250 km radius of Woomera. Heavy showers with this system also brought a wet end to a wet autumn for this part of the Country. Roxby downs saw 3mm in 10 minutes just after midday, while Minnipa has seen 12mm since 9am. These showers are a fitting close to this soaked autumn. During the season, Coober Pedy recorded 176.2mm, over 6.5 times the seasonal average. Despite having seen the peak of storms in SA this afternoon, a band of thunderstorms along the eastern flank of the trough will be evident tomorrow as the system pushes east. As a relatively warm surface airmass rises through the atmosphere, the upper level pool of cold air will accentuate the temperature difference and therefore accelerate instability. This intense lifting will sustain thunderstorms on the trailing edge of the system. Between these two bands of storms however is where the rain will be heaviest. Heavy showers over SA's North East Pastoral and Mid North will extend into NSW's Upper and Lower Western Districts tomorrow, where isolated falls of up to 20mm are a chance. Sunday, however, is likely to be the wettest day for much of NSW. Isolated falls up to 100mm are a chance over the Central West Slopes and Plains with widespread falls of 50mm likely. An area of convergence just offshore, will also brings the risk of falls in excess of 50mm along the coast from the Illawarra to the Hunter on Sunday.