A broken line of thunderstorms stretches from Charleville to Melbourne along a trough, producing periods of heavy rain and locally severe storms. The line of storms is associated with a deep trough that has been working its way across the country over the past few days. Areas of WA and SA have seen some of the heaviest rains in years with this same trough. On Thursday, Giles in the WA interior reported a 24 hour rain total of 70mm, which was its heaviest one day rain total in more than 10 years. In SA yesterday, Whyalla was hit by two severe storms within hours of each other and reported 55mm of rain, its heaviest December rain in the last 32 years! Gluepot in South Australia's Northeast Pastoral District reported 102mm in the past 24 hours, the highest one day rain total for all months in their 11 years of records. The trough has been so intense due to the combination of a few factors. The trough began to the west of Australia with an unseasonably cold upper level pool of air, that helped Perth to get its highest December rains in years. The trough moved east and began to interact with a strong tropical moisture feed coming down from the Timor Sea. The final piece of the puzzle was when an inland trough moving west from the east coast of Australia joined in to cause the intense storms across SA yesterday and this morning. The strong area of instability continues to move further east today with the movement of this trough. Widespread storms are expected to stay west of the ranges in NSW and QLD today, but still produce frequent lightning, heavy downpours and possibly high winds. The area of storms will move east on Monday with the potentially severe storms making their way to the east coast, with areas along the southeast coast of NSW at risk of experiencing localised flash flooding and high winds with these storms. The trough will weaken by Tuesday as a strong ridge of high pressure just off the east coast of Australia will block any further eastward progression and weaken the chance of widespread storm development for NSW.