Thunderstorms, hail, snow, rain and severe gales are all possible today as a strong cold southwesterly airflow lies over New Zealand.

WeatherWatch says gale to severe gale winds are likely for many coastal spots and the upper North Island in particular.

"Thunderstorms, hail and snow are also in the forecast, it will all ease and clear this evening,' says a WeatherWatch spokesperson.

For Bay of Plenty, Northland, Auckland and Waikato, the weather forecast is for rain with heavy falls.

"Thunderstorms and hail possible then easing to showers in the afternoon with sunny spells breaking through, showers clear evening.

"Strong to gale southwesterly winds, severe gales possible then easing later in the day."

Temperature highs for these four regions are expected to be between 13-15 degrees Celsius.

Desert Road (SH1)
Snow is expected about higher parts of the road Saturday morning, and 2 to 4 cm of snow may settle near the summit, with lighter flurries down to 800 metres.

Western North Island (including Central North Island)
Rain with heavy falls, perhaps thunder and some hail, easing to a few showers in the afternoon, clearing evening. Snow to 700m, perhaps getting a touch lower later in the day before showers clear. Northwesterlies change to the south in the morning, dying out at night.
Highs: 7 – 14

Eastern North Island
Rain with heavy falls for Wairarapa spreading northwards in the morning, hail possible, easing to showers mid to late afternoon from the south, clearing evening. Snow lowers to 700m, perhaps a touch lower before showers clear but it will only be a few flurries at that point. Southwesterlies strengthen, gale to severe gale winds develop about coastal areas then dying out at night.
Highs: 12 – 15

Wellington
Morning rain, possibly heavy with hail and snow to 700m, easing from afternoon, clearing in the evening. Strong to gale southerlies die out later in the day (severe gales through Cook Strait).
Highs: 11 – 12

Marlborough & Nelson
Showers, heavy in the morning for Marlborough with a chance of hail and snow to 700m, easing from afternoon with a few sunny spells breaking through, drying out in the evening with southwesterlies dying out.
Highs: 13 – 15

Canterbury
Showers, heavy for North Canterbury with hail. Snow to 400m. Conditions start to ease from afternoon with the snow level lifting, clearing up for South Canterbury then clearing further north in the evening as strong cold southwesterlies die away.
Highs: 11 – 14

West Coast
Sunny for South Westland, showers further north clear in the afternoon with sun increasing. Showers push back into Fiordland from afternoon further south. Southwesterlies freshen up in the afternoon then easing at night.
Highs: 11 – 15

Southland & Otago
Showers, possibly heavy in the morning with hail and snow to 400m then gradually backing away with the snow level lifting, clearing at night as gusty southwesterlies (strong to gale about the coast) tend northwest.
Highs: 9 – 12