Issued at 2:24pm Wednesday 22 May 2013
Valid from Friday 24 May 2013 to Monday 27 May 2013
Cold southerly flow late Thursday is expected to weaken Friday as a ridge passes east. On Saturday, a low is expected to approach the upper North Island,while a cold front approaches the lower South Island. The low is expected to move quickly over the upper North Island from Northland to East Cape, with a burst of heavy rain and strong winds. There is a low risk that rain accumulations could reach warning criteria about Northland, Coromandel Peninsula and East Cape (as indicated on chart) during late Saturday and Sunday.
Rain is expected to develop about the South Island west coast on Saturday ahead of an oncoming cold front, with strong to gale northwesterlies about eastern areas of the South Island including Wairarapa and Wellington. This front brings strengthening westerlies on Sunday, which ease for a time, then return on Monday before the flow tends southerly. There is a moderate risk that rain accumulations could reach warning criteria about Fiordland during late Saturday and early Sunday, and that westerly winds could reach severe gale at times about Southland, Otago, inland Canterbury and Marlborough, Wellington, Wairarapa and Cook Strait during Sunday and Monday.
Temperatures are expected to get colder in a far south during Monday, with snow expected to low levels about southern Fiordland and Southland. There is a low confidence that snow accumulations will reach warning criteria above 300 metres about southern Fiordland and Southland late Monday.
Low confidence:
A 20% likelihood (or 1 chance in 5) that the event will actually happen.
Moderate confidence:
A 40% likelihood (or 2 chances in 5) that the event will actually happen.
High confidence:
A 60% likelihood (or 3 chances in 5) that the event will actually happen.
New issues of this forecast are made available on this site at or before 16:30NZST. To ensure you have the latest information use your browser's refresh function.
