This just in from the Metservice
HEAVY RAIN AND SNOW FOR WESTERN PARTS OF THE SOUTH ISLAND AND CENTRAL NORTH ISLAND, WITH SEVERE NORTHWEST GALES POSSIBLE ABOUT WELLINGTON AND WAIRARAPA TONIGHT (NOTE: WARNING UPDATED TO ADD HEAVY RAIN TO THE TARARUAS, MT TARANAKI AND THE ALREADY SATURATED CENTRAL NORTH ISLAND HILL COUNTRY)
A strong disturbed northwest flow is expected to cover northern and central New Zealand through to Sunday. A series of fronts embedded in this flow are forecast to bring periods of heavy rain and squally thunderstorms to western parts of both islands during this time.
Lowering temperatures behind the first and most active of these fronts crossing the South Island today and North Island early Friday morning are expected to bring heavy snow down to quite low levels in the west of the South Island (the higher passes across the Alps are already affected), and also heavy snow about the central North Island high country. Many of the higher roads in these areas are likely to be affected, including all the main South Island passes, the Desert Road, roads skirting the west of Tongariro National Park, the Napier-Taupo highway and the Gentle Annie Route from Taihape.
Heavy rain is also expected about the Tararua Ranges and Mt Taranaki, with significant rainfall also likely about the hilly country from inland Taranaki to the Central Plateau, including the Taupo catchment.
For the latter area, the forecast rainfall totals would not ordinarily warrant a warning, but given the already saturated conditions, rivers there will need watching, and slips and local surface flooding are possible.
A period of severe northwest gales is also likely about parts of Wellington and Wairarapa overnight Thursday, especially exposed hill tops, where winds could gust to 120 km/h for a time. Locally strong wind gusts are also likely for other northern and western areas from Taranaki up to Northland early Friday morning, associated with thundery squalls (See latest Severe Convection & Thunderstorm Outlook on www.metservice.com for more information).
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