Depression Sunday 29th July onwards

[spwill]

My Parents in Mosgiel tell me the rain is very heavy there with surface flooding along the street.

Rain clearing here,had a couple of Thunder claps. looks to be a storm Hamilton way as well.

[RWood]

sw_windbow wrote:

Unlike the sodden North there's not much heavy rain in these parts - ever - and I'm praying like a drought-stricken farmer that it does eventuate.


"Ever"? I assume you're not serious.

Slight exaggeration there, but only slight. Dunedin does get quite spectacular downpours, like the one in Feb '05 that broke the roof at Fisher & Paykel's factory, and then flooded buildings in Lower Rattray St, and many other parts of the city.

There are the more sustained events too, like in April last year there was the quite considerable event that blew out Silverstream and flooded Mosgiel. The Leith on that occasion remained mostly within its banks.

But sustained heavy rain is uncommon. I did a quick check of the rainfall stats for Mussleburgh over the last 81 years. It would appear the monthly average rainfall is around 50mm. By my calculations there has been on average one month every 3 years and 3 months where the total rainfall exceeds 150mm. I counted a total of 25 of those months over the 81 years. I saw only 8 or 9 months where the total exceeded 200mm. March and April 1968 were exceptionally wet with 479mm between them. The highest total I found (though I wasn't looking very hard) was for the month of April 1923 with 294mm. I suspect that might have been the month of the great Leith Flood that inundated much of North Dunedin and bought a collosal volume of rocks and debree into the lower stretches of the stream bed.

Comparing Dunedin's monthly rainfall totals with almost any other part of New Zealand, and in particular the Northern areas, where events of 100mm over 24 hours can be expected every year, if not every 6 months, I think it is fair to say Dunedin doesn't get much heavy rain. This event so far hasn't been particularly heavy, but still looks like it might catapult July's total to one of the highest of the year. And the month includes 4 weeks of more or less dry weather!

Yes, those numbers tally with the info I have. Of course, some of the higher areas on the western flanks of Dunedin are quite a bit wetter. It's true that seriously heavy daily rainfalls (say 75mm) are uncommon in Dunedin - also (eg) in Invercargill, drier parts of Canterbury and Manawatu (which however got really clobbered in Feb. 2004).

When I lived in Dunedin I found the modest rainfall tended to compensate for other factors - eg 1964 & 1966 were both pretty cloudy but also rather dry years.

PS - in April 1923 my father was a 10-year old living in the Milton area on a small farm. His exploration one day of some flooded bits nearly got him drowned - he turned back when someone yelled at him.

[NZstorm]

I think it is fair to say Dunedin doesn't get much heavy rain.

Dunedins geography means it is cut off from moisture.

Todays rainfall is a rare example of a heavy rainfall set up for the region. The air is moist and unstable on the front and a strong onshore wind adds an orographic component too.

[mikestormchaser]

Im not quite sure how much mm of rain we got in Christchurch but it sure did pelt down from as Tony said, 10 pm onwards.
Nice sunny day here and afternoon as i type.

[Fujita Phil]

Certainly wet here. Over 92mm now. Roads closes everywhere. You need a 4WD at Cherry Farm to head south to Dunedin. Mosgiel has it's fair share of floods along with many places around town.

The rainfall amount is slowing each hour but the ground has had it's full

[Andy]

100mm for Dunners, and only 5mm in Alexandra a 100km inland. Gee i was hoping i would get 10mm out of this low, drizzel at the moment so we might get there.

I hope everything is ok on the coast.

[Storm Struck]

50mm in my gauge overnight a well earned soaking flooding signs out this morning but was gone when I went through. Paddocks have turned to lakes in some areas, a good example is Queen Elizabeth drive oppisite Philpots rd.
Another accident on Johns rd this morning Andrew too, car skidded and flipped after avoiding the flooding cones on the road.
Any news on the rivers down south, high tide must be coming soon?.
Cheers
Jason.

[Michael]

The map looks exactly like 3 weeks ago but the whole lot is furtur south with a polar high well south of Stewart Is.

[Manukau heads obs]

100mm is alot of rain in any ones book

[NZ Thunderstorm Soc]

Nothing on the news about heavy rain/flooding in Dunedin or isn't that really important???
If Dunedin was in Northland or a suburb of Auckland, might have been a different story
The Invercargill/Rakaia rain radars don't cover the Dunedin area very well, maybe a radar is needed down there, instead of installing one around the area around the BOP?
Dunedin is a major NZ city

JohnGaul
NZTS

[NZ Thunderstorm Soc]

I was wrong
It featured on the weather news on TV One

JohnGaul
NZTS

[spwill]

Nothing on the news about heavy rain/flooding in Dunedin or isn't that really important???
If Dunedin was in Northland or a suburb of Auckland, might have been a different story

TV One news not doing their job.

[NZstorm]

Nothing on the news about heavy rain/flooding in Dunedin or isn't that really important???

Recent snow in Dunedin got good TV1 news coverage.

[Manukau heads obs]

nice to get another round of lightning and thunder in the Auckland area
we have been doing well lately!
(compared to the last few years)
could be a good spring for thunderstorms coming up?

[Gary Roberts]

Drove to Oamaru via Weston at lunchtime. Heavy road flooding from Georgetown out to the coast. I had an ominous feeling about it since I hoped to get out again by the afternoon.

Sure enough almost all the highways and roads were closed. Had to detour out to Seven Mile Road and even then I had water lapping against the windshield and the radiator fan blades were howling.

The river through the middle of town had burst its banks and made a hell of a mess. Glad I'm not on the clean-up detail for that one. It'll be ages before the town dries out because it never stops raining in Oamaru.

Weird thing is that it wasn't even raining all that heavily, just steadily. It's been relatively dry out east recently (or at least by their standards) so that probably compounded the problem.

[Fujita Phil]

It'll be ages before the town dries out because it never stops raining in Oamaru.

I think you have a dislike for Oamaru more than Auckland Gary You must only head down there when it rains

Had to detour out to Seven Mile Road

Ah memories... Ford Escort, straight road... I think I got it up to 100km once

[spwill]

Photo of your Storm Brian from here.

[tich]

Recent snow in Dunedin got good TV1 news coverage.

The general public throughout NZ tend to asscoiate Dunedin more with heavy snow than heavy rain.

Supposed to be mostly fine tomorow in Chch, after some early fog - and we'll be in the middle of a big low rather than a big high. Eye of the storm scenario?

[Gary Roberts]

I think you have a dislike for Oamaru more than Auckland Gary You must only head down there when it rains

It seems as if it's raining every time I'm near the place!

Actually I think Oamaru is a beautiful place. Just a shame about the weather!

Ah memories... Ford Escort, straight road... I think I got it up to 100km once

Tonight my heart rate was the only thing that fast. Driving what amounts to a hotted up Corolla through deep water in the dark is not my idea of fun!

[RWood]

Average rainfall around Oamaru sites is actually quite low.

[sw_windbow]

On the topic of heavy Dunedin rain, here's a YouTube url to a video I took of the 2005 Waterbomb. Its taken from the summit of Signal Hill, probably not far from Fujita Phil's place.

My old camera can only mpeg 1 minute of tape recording at once, so there's three videos. Its about 2 minutes 40 in all.

http://www.youtube.com/watch?v=ayJMyNOOx_0" target="_blank

[Andrew Massie]

Just for the record, my grand total was 63mm in the last downpour.. Biggest one for a while, found some blocked guttering at my place! <sigh>

Is anything else extreme expected from this Low?

[NZ Thunderstorm Soc]

Is anything else extreme expected from this Low?

No. ...unless you live in Auckland

JohnGaul
NZTS

[Razor]

No. ...unless you live in Auckland

JohnGaul
NZTS

Or Tornado Alley in Taranaki...

[Willoughby]

A balmy 17.4C today with 12C dewpoints.. that's twice now in July we've hit 17C!

Looking interesting early next week with GFS and ECMWF progging a strong pulse of cold air to the west of Fiordland around a long wave trough.