Tristan Meyers, 18 Apr 2015, 6:51 AM UTC
East Coast Low off NSW Coast
An East Coast Low should form off the New South Wales coast this Monday, bringing heavy showers, strong winds and dangerous surf to much of the coast.
The low will form in part due to an influx of cold, southerly winds from an approaching cold front colliding warmer, tropical winds from the north steered by a high pressure system in the northern Tasman Sea.
Also aiding in its formation is an upper trough associated with this front. Once this upper-level system reaches the coast, it will deepen a coastal trough.
The combination of upper-level instability and surface mixing will cause a low to form.
Although winds will become gusty along the coast from Sunday, the strongest winds look to develop from around Batemans Bay to Foster on late Monday or Tuesday. Here, sustained winds of up to 50 km/h could be expected for places around Nelsons Bay, with gusts clocking up to 90 km/h.
The power of these winds will produce giant swell. Although waves over 6 feet are looking to break on Sydney's shores, 10-12 foot waves may crash on southerly facing beaches in Newcastle. With these crazy winds and intense swell, surfing and water sports activities are not advised next week.
Showers also look to be widespread and heavy. The strong onshore component to the winds means that there will be plenty of moisture about in the atmosphere, most of it finding its home on our homes and workplaces. On Monday, widespread in excess of 20mm is likely for the coast, stretching from Wollongong to Lismore, with places just to the south of Port Macquarie possibly seeing totals as high as 50-100 mm.
Come Tuesday, the rain may not be as widespread, but will be more intense for Sydney up to Port Macquarie. Showery conditions look to persist into Wednesday with Sydney, Wollongong and Newcastle currently looking to pick up over 30mm.
With the addition of this rain, its looking like many places around the South Coast, Illawarra, Sydney and the Hunter districts will reach or exceed their monthly average of rainfall.
Conditions are looking to ease slightly on Thursday. Hopefully, by the end of the working week, wind and heavy rain will ease to just a few lighter coastal showers.
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