Looks like Thunderstorms are possible over parts over the North Island on the 12th and 13th.
The 13th looks like a convergence line/sea breeze setup with unduly cold upper temps, the breeze should provide sufficient moisture.
Metservice has got a moderate risk from the mid to upper north island.
Metservice wrote:A deep pool of cold air should move slowly east across the North Island on Tuesday and widespread showers are expected. There is a moderate risk that afternoon heating will produce thunderstorms where sea-breezes converge from about Taupo northwards. Any thunderstorms that form may have hail 10 to 15mm in diameter and rainfall rates approaching 25mm per hour.
There is also a low risk afternoon heating may produce isolated thunderstorms over central Otago.
Elsewhere, no risk of thunderstorms or significant convection.
You do not have the required permissions to view the files attached to this post.
I did wonder about thunder for Waikato today as recent GFS runs have bought upper level cooling in a bit earlier and radar has showed showers lines down there.
The clearance of that high cloud has reached West Ak, some TCu around.
Metservice has amended the Thunderstorm outlook 2 times today
The latest:
Amended to push thunderstorm risk areas into Waikato.
A cold southerly change is spreading up the North Island. There is a moderate risk of thunderstorms developing on the leading edge of this change over the central North Island from Taumarunui to inland Hawkes Bay to Waikato and a lower risk over a larger surrounding area. Any thunderstorms that do develop may be accompanied by hail 10-15mm in diameter and heavy rain with rates 10 to 20mm per hour.
Also, there is a low risk of afternoon heating triggering thunderstorms over the ranges of northwest Nelson.
Elsewhere, no thunderstorms or significant convection expected.
You do not have the required permissions to view the files attached to this post.
There was a storm over northern Waikato last 30mins, but there was no real sunshine down there today
I will chase tomorrow, likely meet up with NZstorm. Brian, we could meet up at Bombay , will confirm a time in the morning but we will probably start the day earlier rather than later, perhaps meet up around lunch time
Chase on alright!
We are under a moderate risk of severe storms, woohoo
Metservice wrote:A deep pool of cold air should move slowly east across the North Island on Tuesday and widespread showers are expected. There is now a HIGH risk that afternoon heating will produce thunderstorms where sea-breezes converge from about Taupo northwards. Any thunderstorms that form may have hail 10 to 15mm in diameter and rainfall rates approaching 25mm per hour. Within this area over western Bay of Plenty, eastern Waikato and northern parts of Taupo, there is a moderate risk that some of these thunderstorms will be SEVERE producing rainfall rates up to 40mm/hr and hail up to 20mm or so due to slow storm motions.
There is also a low risk afternoon heating may produce isolated thunderstorms over central Nelson, Buller and Marlborough, and also central Otago and central Southland.
Elsewhere, no risk of thunderstorms or significant convection.
You do not have the required permissions to view the files attached to this post.
Some respectable CAPE and LI Numbers being pulled tomorrow afternoon. 800j/kg and LI down to -3 in areas of the Waikato.
Upper level temps cooling to a very chilly -26°C, Hail is definitely in the mix if any decent convection takes place.
SFC forecasted temps across the Waikato region are around 19°C to 17°C.
Attached CAPE/LI Chart and Forecasted Sounding for the 13th at 3 PM NZDST. Note: GFS can often underestimate a Sea Breeze's Moisture content, even if Sea Breeze occurs so keep that in mind when using the sounding
You do not have the required permissions to view the files attached to this post.
