A series of incredibly lightning-active thunderstorms struck the Central Coast in NSW on Monday night, producing thousands of lightning strikes within a matter of hours. A low pressure trough sweeping across NSW on Monday caused warm and moisture laden air to clash with a cooler southerly change, triggering the intense storms. The series of thunderstorms acted like a lightning factory, generating around 17,000 strikes within a 50km radius of Gosford in just four hours. Mt Elliot near Lisarow registered 61mm of rain during the storm outbreak, which is its heaviest fall in two months. Gosford received 26mm of rain in just 20 minutes, which is enough to produce localised flash flooding. According to Ausgrid, power was cut to about 6000 customers after one of their poles was hit by lightning in Berkeley Vale. The trough has moved further north today and will help generate thunderstorms over northeast NSW this afternoon and evening. Some of these storms may become severe.