Storms Central & Eastern 13/12/2017

[Richard]

Possible storms today is worthy of a thread considering the severe threat for northern half of Canterbury and Marlborough, as well as Gisborne and northern Hawkes Bay

From the Met Service

Valid to: Midnight Wednesday 13 Dec 2017

Issued at: 8:39am Wednesday 13 Dec 2017

Temperatures aloft are expected to cool this afternoon and evening bringing instability to many central and southern areas.

This cooling combined with low level wind convergences should lead to daytime cloud buildups producing scattered showers and thunderstorms about Gisborne and Hawkes Bay during the afternoon and evening. These thunderstorms will be accompanied by localised heavy rain and hail. There is a low risk a few of the thunderstorms could be severe over Gisborne and northern Hawkes Bay producing localised downpours in excess of 25mm/hr and large hail. Rainfall rates of this intensity can cause surface and/or flash flooding, while large hail can cause damage to crops.

Further south, a freshening south to southeast flow and cooling aloft is expected to lead to thunderstorms embedded within broader areas of rain about parts of Buller, Marlborough and inland Canterbury during the afternoon and evening, with localised heavy rain of 10-25mm/hr and hail. Additionally there is a low risk a few of the thunderstorms could be severe in the hills and ranges of Canterbury and Marlborough producing localised downpours with rates of 25 to 35mm/hr.

As this southeasterly wind change pushes through Nelson and the lower North Island late in the day, there is a moderate risk of the change triggering thunderstorms about parts of Whanganui, Manawatu, Horowhenua, Wairarapa and Nelson from this evening with localised heavy rain and hail.

A broad low risk of thunderstorms covers remaining parts of central and southern New Zealand through much of the period, as indicated on the chart.

[snowstormwatcher]

Very heavy rain in timaru city this morning..

[Razor]

Very heavy rain in timaru city this morning..

Send it up mate. 0.0mm in ChCh Botanic gardens yesterday, but some outer suburbs got several mm's

[Chris W]

Some pretty decent cloud build-ups in town this morning, although we are in the low risk area.

[Richard]

All build ups are east and south, nothing around the mountains which is unusual

[mikestormchaser]

Today isn't actually a bad set up with an onshore NE aswel. Be interesting to see what happens later

[NZ Thunderstorm Soc]

Very heavy rain in timaru city this morning..

That heavy rain missed us here, only 2.2mm till to noon today.
ChCh looks good with a keen ENE at the moment

[Richard]

Warming up nicely with a light SE wind, 20deg, clouds building all round

[NZ Thunderstorm Soc]

Grey/Hoki looks as though they might be in for a storm or 2 ?

[snowstormwatcher]

Very heavy rain in timaru city this morning..

That heavy rain missed us here, only 2.2mm till to noon today.
ChCh looks good with a keen ENE at the moment

Yes very coastal only 5mm at home near Pleasant point..

[Chris W]

Looking pretty dark over towards the hills, Chch about to get something heavy.

[Richard]

Heavy shower here but no thunder yet.

[Thunder081]

Some towering cumulus near Levin

DSCF6518-r.jpg

DSCF6519-r.jpg

[Richard]

Looking promising for Levin but i see they moving NE.

Been a couple of rumbles out to the east of here

[dogmelon]

Well, A severe thunderstorm warning has been issued for two storms eying up Gisbourne. Well done Metservice for drawing that one up correctly.

Does Paul Mallinson still come in these forums with his tidbits of really interesting info?

[NZ Thunderstorm Soc]

Does Paul Mallinson still come in these forums with his tidbits of really interesting info?

No.

[dogmelon]

Does Paul Mallinson still come in these forums with his tidbits of really interesting info?

No.

That's a shame. I enjoyed his comments.

[Willoughby]

^He retired I believe.

Looks like a couple of decent thunderstorm cells by Lake Waikaremoana and inland of Gisborne last couple of hours. Crosses mark cloud-to-ground lightning strikes.

waikeremoana.JPG

[Razor]

^He retired I believe.

Looks like a couple of decent thunderstorm cells by Lake Waikaremoana and inland of Gisborne last couple of hours. Crosses mark cloud-to-ground lightning strikes.
waikeremoana.JPG

That would be this one, active warned right now.

[Willoughby]

Good CAPE and instability with this ACCESS-Regional (BoM) modeled sounding for just inland of Tolaga Bay where a third thunderstorm got up.

[Chris W]

Been hosing it down in New Brighton for about half an hour, but no thunder.

Very squally with some serious gusts.

[NZ Thunderstorm Soc]

All over bar the shouting by the look of it down here.
Even lit the fire tonight

[Thunder081]

Reports of thunder in Upper Hutt at around 5:40pm

[BeaconHill]

Just heard one rumble of thunder in the distance to the ESE of Wellington airport. Nzapstrike.net is showing some reasonable activity out in Cook Strait from the cells that formed earlier over Marlborough. Fingers crossed they get here as we desperately need any rain we can get.

Rain JUST starting to get heavy now

[Richard]

Had a report from a farmer near Greta Valley who recorded 34mm of rain from Wednesday's storm which mostly fall in about 10mins.