Storm Struck wrote: So very squally as you say and messy thunder/hail set up for canterbury tomorrow.
, that could be on the cards for tomorrow,Jase
There will be an abundance of moisture I believe esp in the North Island, the moisture when lifted in convection creates latent heat which creates more CAPE and therefor more instability.Richard wrote:But i thought very cold air aloft was needed to produce storms,can someone explain the difference with tomorrow's set up.
The 00z GFS run is thinking the southerly change is a Canterbury Coast event.During Monday afternoon and evening, a sharpening trough, preceded by very humid northerlies and followed by much cooler southerlies, is expected to move across the country.
In the northwest of the South Island, the risk of thunderstorms diminishes to low, while much of the North Island is covered by a low risk. A moderate risk covers central parts of the North Island as the trough moves eastwards, as indicated on the chart. Any thunderstorms here are likely to be squally with gusts of 90-100km/h and accompanied by heavy rain of 10-25mm/hr.
In the east, very strong daytime heating ahead of the southerly change is forecast to make for very unstable conditions, and there is at least a moderate risk of thunderstorms from South Canterbury to Wairarapa with the change.Thunderstorms here could bring hail of 5-15mm and heavy rain of 10-20mm/hr.In Canterbury, there is an additional low risk that one or two thunderstorms may become SEVERE producing damaging wind gusts (in excess of 110km/hr) and hail in the 10-20mm range.
wow 49 in waiuku!NZstorm wrote:10mm in Grey Lynn.
49mm at Waiuku!
Looks like a warm front.
Metservice:
A front is forecast to cross the South Island today and the North Island tonight or during Tuesday. This front is preceded by a warm, humid northerly flow bringing rain to much of the country, with some heavy falls, as per the latest Severe Weather Warning and Watch. The front is followed by a strong, colder southerly flow.
There is a moderate risk of thunderstorms over Westland, Buller and Nelson from later this morning through the afternoon, which could locally boost rainfall rates up to 25mm per hour and possibly more about the ranges.
There is also a moderate risk of thunderstorms from south Canterbury up to Wairarapa this afternoon and evening associated with the strong southerly change as it heads north. Thunderstorms here could bring hail of 5 to 15mm in diameter,locally heavy rain of 10-25mm/hr and strong wind gusts around 100 km/h. About parts of Canterbury and the Kaikoura Coast, there is an additional moderate risk that one or two thunderstorms may become SEVERE producing damaging wind gusts in excess of 110 km/hr, as well as hail of 10 to 20mm in diameter and possibly a small tornado.
Meanwhile, over the North Island, a trough ahead of the front, together daytime heating and very humid conditions is likely to produce thunderstorms in western areas later this afternoon and early evening extending across to Bay of Plenty tonight. There is a moderate risk of thunderstorms over this broad area,as indicated on the chart, with a lower risk extending into the ranges of Gisborne and Hawkes Bay. Thunderstorms here are likely to produce locally heavy rain up to 25mm per hour and strong wind gusts around 100 km/h. There is a low risk of one or two thunderstorms could become SEVERE in the west from Northland down to the Kapiti Coast producing downpours with rates over 25mm per hour,damaging wind gusts in excess of 110 km/h and possibly a small tornado.
