Rain one side, heat the other in NSW
The Great Dividing Range has certainly divided the weather over southern New South Wales, as it rains over the Snowy Mountains, and sizzles over the South Coast.
With gusty and humid northwesterly winds blowing over the region, areas of the Snowys have been recording some steady rainfall. Cabramurra has recorded the most, with 7.4mm falling in the gauge between 9am and 2pm on Thursday. Further light falls of 3.0mm and 1.4mm have fallen over Australia's highest rain gauges at Perisher and Thredbo respectively.
Further east, Bega has reached a searing 31 degrees by 2pm, with Moruya close behind hitting 30 degrees. Merimbula and Gabo Island both were sitting at 29 degrees about 2pm. These temperatures are fairly unusual for April, with temperatures about 8-9 degrees above average in each of these locations.
This strange division is due to a meteorological phenomenon called the Foehn Effect. When a mountain range blocks an airflow, it forces the air upwards, often causing a buildup of clouds and increases the chance of rain and thunderstorms over the windward side.
On the other side, the now drier air descends the lee side of the mountain, and warms up rapidly due to the change in pressure. The end result is a wet, cloudy day over the mountains (Snowys) and a warm and sunny day on the other side (South Coast).
Image: Satellite, winds and rainfall observations clearly demonstrates the Foehn effect over southeast NSW on Thursday
A cooling southerly change will start to make its way up the coast from the late afternoon, bringing much cooler days and mornings for the next week over the South Coast.