Thunderstorm Outlook
Issued at 7:34am 26/07/2026
Valid from 7:34am 26/07/2026 to Midnight 26/07/2026
A trough and shallow low pressure system embedded in a west to northwest flow move quickly eastwards over northern New Zealand this morning. Another trough is expected to move northeastwards over northern New Zealand this afternoon and evening, bringing a southerly wind change. For Northland, Great Barrier Island, and Auckland north of Orewa, there is a moderate risk of thunderstorms until late afternoon, then a low risk that continues into the early evening, as depicted on the chart. Any thunderstorms that occur will likely be accompanied by heavy rain with rates of 10 to 20 mm/h, and small hail. For Auckland from Orewa southwards, and Coromandel Peninsula north of Tairua, there is a low risk of thunderstorms until late afternoon. There is minimal risk of thunderstorms or significant convection elsewhere in New Zealand today.
Issued at 7:10pm 26/07/2026
Valid from Midnight 26/07/2026 to Midday 27/07/2026
There is minimal risk of thunderstorms or significant convection during this period.
Issued at 7:56am 26/07/2026
Valid from Midday 27/07/2026 to Midnight 27/07/2026
There is minimal risk of thunderstorms or significant convection during this period.
Severe Thunderstorm Criteria
In New Zealand, MetService classifies a thunderstorm as severe if one or more of the following criteria are met:
Heavy rain (from thunderstorms):
Rainfall of 25mm/h, or more.
Large hail:
Hailstones 20mm in diameter, or larger.
Strong wind gusts (from thunderstorms):
Gusts of 110km/h (60 knots) or stronger.
Damaging tornadoes:
Fujita F1 - i.e. wind speeds greater than 116km/h (63 knots) or stronger.
Note: some tornadic systems such as funnel clouds, waterspouts and small land-based tornadoes are possible with thunderstorms that may not be classified as severe.
