Warm Gales, Rain & Snow - Jul 22-24

[jamie]

Oh nice a cg with powerful thunder. Most unexpected.

Today's winds were strong. Max gust 84. Max avg 74

[NZstorm]

Just saw lightning to distant south from that storm down your way Jamie.



A shortwave trough in the westerly flow will be approaching the North Island later tomorrow with some lightning potential.
Moves onto Auckland Waikato early Tuesday. Possibly a system worth keeping an eye on.

[shovelopikis]

thunder and awesome hail squalls today, wild weather for sure, woke at 11pm last night and bed was shaking from a drawn out gust pounding the house.

[Richard]

17mm of rain today which has been so welcome

[Manukau heads obs]

just out of interest I see that the rain accumulation Map is Back from M/S
http://www.metservice.com/maps-radar/lo ... l-24-hours

I presume its rain radar based , or?
certainly shows the shadow effect of the ranges but if the rain is intense enough then you will get spill over rain Richard?
(map updates at 11am)

[Nev]

Total of 35mm here for this event and a very blustery weekend in the Gulf.
I see Whangaparaoa recorded gusts to 106 km/h yesterday arvo.

[jamie]

There was quite a bit of hail in the showers from early evening onwards.

My local part of Hamilton, rototuna had a lightning strike right above it judging by the Facebook posts on the local page

[Richard]

just out of interest I see that the rain accumulation Map is Back from M/S
http://www.metservice.com/maps-radar/lo ... l-24-hours

I presume its rain radar based , or?
certainly shows the shadow effect of the ranges but if the rain is intense enough then you will get spill over rain Richard?
(map updates at 11am)

I was thinking that myself yesterday, 'is it radar based'?, but there's no way its going to be accurate given the large areas of NZ that are not covered by radar.

[Nev]

I see Cape Turnagain, Wairarapa, has had gusts to 100 kts (185kmh)!
is the unexpected snow to low levels a warm advection event (due to a big drop in the barometer ?)

MS have gusts to 194 km/h at Cape Turnagain late Sunday morning (although it may have been higher as the day's data is incomplete). That would make it the 10th highest gust recorded there since records began in late 2009 - the highest being 210 km/h in Nov 2014.

[Thunder081]

I see Cape Turnagain, Wairarapa, has had gusts to 100 kts (185kmh)!
is the unexpected snow to low levels a warm advection event (due to a big drop in the barometer ?)

Where are you getting the gust data from?

[Thunder081]

Maximum gust yesterday at the Kelburn pole instrument was 107 kph, not very impressive at all. Local winds didn't even rate a mention in the Stuff headline stories. The wind overnight failed to pass our house's "wake up" test, too. Still very windy however with bright sunshine for the most part. MTD rainfall is well down on the average.

But still there was 153 km /h gust the Rimutaka Summit (data from Metconnect)

Rimutaka Summit Wind 153kph2.JPG

[Manukau heads obs]

Where are you getting the gust data from?

Predictwind.com
it was actually over 100kts when I looked.going by the scale on the graph

[Richard]

Had a interesting discussion yesterday with my NIWA contact regarding there AWS in my paddock and the wind speeds that it recorded over the weekend storm. He pointed out that winds speeds can be as much as 50% more at 5m above ground compared to 2m which the one in my paddock is, this makes sense. So how many of the sites that were mentioned in this threat apart from hill top or other exposed sites at 5m or higher? It becomes a bit of a gray area when a given wind speed is reported, there's just to many variables.

[Manukau heads obs]

after 10 m its a dminishing return
10m masts are standard (which is surprisingly tall)

http://belfortinstrument.com/height-win ... ts-ground/

[jamie]

Sometimes I wonder if my exposed house gets bigger westerly winds than the anemometer that is a good 10m off the ground on top of a small hill.