Severe Weather Outlook

Valid from Monday 20-Nov-2017 to Thursday 23-Nov-2017

Issued: 01:46pm Saturday, 18-Nov-2017

From Monday to Thursday an area of high pressure is expected to bring settled weather to New Zealand. No severe weather is expected.

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 16:30 NZST

Thunderstorm Outlook

Valid to Midnight Saturday, 18-Nov-2017

Issued: 08:08am Saturday, 18-Nov-2017

No thunderstorms or significant convection expected during this period.



Valid to Noon Sunday, 19-Nov-2017

Issued: 08:21pm Saturday, 18-Nov-2017

No thunderstorms or significant convection expected during this period.



Valid to Midnight Sunday, 19-Nov-2017

Issued: 08:21pm Saturday, 18-Nov-2017

No thunderstorms or significant convection expected 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 25 millimetres per hour, or more.

Large hail:

Hailstones 20 millimetres in diameter, or larger.

Strong wind gusts (from thunderstorms):

Gusts of 110 kilometres per hour / 60 knots or stronger.

Damaging tornadoes:

Fujita F1 (wind speeds greater than 116 kilometres per hour / 63 knots) or stronger.