There was a big low sitting out to the east of the South Island, driving quite an "active system" over the country today.
A front was crossing the central North Island this morning, spreading rain and showers from Waikato north.
Auckland could see some morning rain, then a few showers, chance heavy and thundery in the afternoon with a high of 22C.
There was a moderate risk of thunderstorms in the central North Island from Auckland, Coromandel, Bay of Plenty and Gisborne down to Manawatu and the Tararua District in the afternoon and evening. Any thunderstorms that eventuated could produce localised heavy rain with intensities of up to 25mm per hour and hail up to 15mm diameter.
"With that big mass of showers swirling around, then add in daytime heating, and there is added impetus for some thunderstorms," Loots said.
In behind the front was a big mass of heavy showers and hail this morning stretching from Taranaki to Christchurch. That system was forecast to ease from the south with a ridge of high pressure building behind it.
Tuesday was looking fine for the South Island while showers continued in much of the North Island.
On Tuesday, Wednesday and much of Thursday, a low was forecast to lie northeast of the North Island, forcing a moist southeast flow onto Gisborne and Hawkes Bay.
The high pressure in the South Island should extend further north Wednesday, bringing fine weather to western and northern parts of the North Island.
Today's weather
Whangārei
Brief rain late morning, then a few showers. Northwesterlies changing southwest late morning. 24C high, 14C overnight.
Auckland
Brief rain about mid-morning, then a few showers, chance heavy and thundery. Northwesterlies changing southwest morning. 22C high, 14C overnight.
Hamilton Morning rain, then a few showers, chance heavy and thundery. Northwesterlies change southwest. 21C high, 10C overnight.
Tauranga Brief rain around midday, then a few showers, chance heavy and thundery. Northwesterlies dying out by early afternoon. 21C high, 14C overnight.
New Plymouth Showers, clearing at night. Westerlies changing southerly afternoon. 20C high, 13C
overnight.
Napier A period of morning rain then a few showers, chance heavy and thundery. Winds becoming light. 23C high, 16C overnight.
Whanganui Rain easing to a few showers before dawn. Westerlies, changing southerly afternoon. 21C high, 14C overnight.
Wellington Cloudy periods, with a few showers. Southerlies becoming strong in the evening. 18C high, 14C overnight.
Nelson Partly cloudy, and a shower or two during the afternoon and early evening. Light winds. 21C high, 12C overnight.
Christchurch Showers and fresh southwesterlies. 17C high, 11C overnight.
Dunedin Showers clearing early morning, then fine spells and evening cloud. Fresh southwesterlies easing. 18C high, 11C overnight.
