General July Weather

[Nev]

Interesting discussion in this story from the Taranaki Daily News about the frequency of tornadoes in NZ's own 'miniature tornado-alley' entitled 'Tornadoes hit insurance companies'.

The Insurance Council says there's anecdotal evidence suggesting that Taranaki is being hit by more tornadoes, and also cites a 2007 NIWA report, which warned that expected climate changes this century included an increase in westerlies along with gale and storm-force winds (although not necessarily an increase in tornadoes).

However, both NIWA and MetService point out that better monitoring just meant that more were being reported, and also that as the region grows, there's 'more potential victims for twisters'.

[Andrew Massie]

Interesting discussion in this story from the Taranaki Daily News about the frequency of tornadoes in NZ's own 'miniature tornado-alley'

HAD to be mini-tornado alley, didn't it?!!!

[Manukau heads obs]

I thought global warming was going to lead to a decrease in the strength of the westerlies (the roaring 40's)
due to the fact the polar regions warm up more compared to the tropic regions, i.e a decrease in temperature gradient and so a decrease in the wind speed

[NZstorm]

I think there is a spike in tornado incidence in NZ during some El Nino periods due to the more disturbed weather and stronger tropospheric flows over NZ.

[Razor]

I'm calling it...winter is done and dusted.

Its officially spring at my place- looks like NW winds and mild temps as far as the eye can see in the forecasts.

[spwill]

Its officially spring at my place- looks like NW winds and mild temps as far as the eye can see in the forecasts.

Cherry blossom and Daffodils are out and the birds are now chirping in the morning.
Yes, perhaps an early spring this year on the back of El Nino.
Currently 15C here, Dp13C, fresh SW, cloudy skies

[Janos]

I'm calling it...winter is done and dusted.

Its officially spring at my place- looks like NW winds and mild temps as far as the eye can see in the forecasts.

Im with you this one Razor....same same down here.

[Storm Struck]

It is looking like a continued mild/warm phase of N-NW winds ahead certainly, which will mean warmer daytime temperature and overnight lows between 7-10C.
Dont be surprised after a continued period of warmer weather, we see a dump of snow in the South Island to sea level.
I wouldnt say winter is over but it is certainly going to be unseasonably warmer for August.

[Andrew Massie]

Gosh there's an echo around here... AGAIN!

[Richard]

I thought global warming was going to lead to a decrease in the strength of the westerlies (the roaring 40's)
due to the fact the polar regions warm up more compared to the tropic regions, i.e a decrease in temperature gradient and so a decrease in the wind speed

My thoughts on this is,i agree that any warming the polar regions would decrease the temperature gradient,but that will only be the case in the summer months.During the spring equinox period when the westerlies are at there strongest there is and never will be any warming due to the very low sun angle, but at the same time regions further north are expecting higher temps therefor at certain times of the year i believe these westerlies will increase.

[gllitz]

I'm calling it...winter is done and dusted.

Its officially spring at my place- looks like NW winds and mild temps as far as the eye can see in the forecasts.

Good call, Razor! Don't see anything nasty/winter like happening again...one never knows, but I think spring is here...the birds/buds on some of my trees around my house seem to think so, anyway...Here's to watching my grass turn greener in the coming weeks!

[CHCH Weather Chaser]

Yes the Northwester here for at least another 7 days and I think we will see 20 degrees reached at some point. Very nice outside today, not a cloud in the sky and not a breath of wind atm. Hopefully plenty of sunshine to dry out the lawn underneath, as I have put mosskiller on my lawn out the front. I take real pride in my lawn Its green and weed free but the dam moss is so annoying! Northwesters will sort that out though! Just 34.4mm so far this month in which 23 of these fell in the first 2-3days of July however, the reason things are still quite wet was due to a very wet may and colder than normal conditions over the past couple of months including July.

[spwill]

Looks like the flow could go onshore for the east of the SI from mid next week.

Cloudy with a few showers here 15C.

[spwill]

I see both Auckland and Christchurch have had a drier/sunnier July than average.

To 6pm yesterday from the Herald, Auckland 147.7hrs sunshine , 111.4mm
Christchurch 134.9 hrs sunshine, 37mm

Sunshine well down for Wellington, 77.8hrs, Dunedin much wetter than normal with 72.2 mm.

[Manukau heads obs]

yes, 21mm drier than normal here for rain
temeperature (still 1 day to go), -0.7 C colder than my normal

so thats a big improvement on the last 2 months for average temperatures!

http://www.weather-display.com/windy/gb ... taout.html

[RWood]

I see both Auckland and Christchurch have had a drier/sunnier July than average.

To 6pm yesterday from the Herald, Auckland 147.7hrs sunshine , 111.4mm
Christchurch 134.9 hrs sunshine, 37mm

Sunshine well down for Wellington, 77.8hrs, Dunedin much wetter than normal with 72.2 mm.

You must be quoting Dunedin Aero - Musselburgh 30-year July average is 67mm, Aero 49mm.

Wellingotn total recovering a little from a terrible start (23 hrs in first 16 days).

[spwill]

You must be quoting Dunedin Aero

So that reading is from the Airport, Musselburgh probably wetter as well.

A wet July for BOP to Gisborne, sunshine down in these areas also.

[Nev]

So that reading is from the Airport, Musselburgh probably wetter as well.

Must be an error (not that uncommon with the NZ Herald figures) ?

NIWA have 41.6mm for Dunedin Aero and 57.8mm for Musselburgh to 9am this morn. So both a little below normal and sunshine above normal.

[GraemeWi]

July 2009 Summary
Henderson, Auckland. S36.86962 E174.62065 41m ASL
Maxiumum Temperature: 17.5°Thursday 16-July-09
Lowest Maximum: 10.7°Saturday 11-July-09
Minimum Temperature: 0.1° Sunday 26-July-09
Highest Minimum: 12.3°Thursday 16-July-09
Total Rainfall: 174.0 mm
Days with Rain: 18 out of 31 days
Most Rain: 30.0 mm Saturday 11-July-09
Highest Pressure: 1026.1 mb Friday 10-July-09
Lowest Pressure: 986.8 mb Saturday 18-July-09

4 days with cb sightings, 2 thunderstorms, 2 frosts made for a good month!

[David]

For me,
mean was 10.5° (mean min 6.4 and mean max 14.6)
lowest temperature 0.4, highest 17.4
Total rain 128mm, year to date 663mm

[jamie]

July summary for Horsham downs

Average temperature 8.3 °C
Average humidity 88 %
Average dewpoint 6.3 °C
Average barometer 1010.0 mb
Average windspeed 12 kmh
Average gustspeed 15 kmh
Average direction 277 ° ( W )
Rainfall for month 135.2 mm
Rainfall for year 676.2 mm
-----------------------------------------------------------
Maximum rain per minute 1.0 mm on day 02 at time 01:18
Maximum temperature 16.0 °C on day 22 at time 13:28
Minimum temperature -3.1 °C on day 26 at time 07:03
Maximum humidity 100 % on day 30 at time 08:43
Minimum humidity 57 % on day 25 at time 14:39
Maximum pressure 1027.4 mb on day 10 at time 10:51
Minimum pressure 987.3 mb on day 04 at time 01:39
Maximum windspeed 66.6 kmh from 339° on day 23 at time 21:20
Maximum gust speed 77.7 kmh from 338° on day 23 at time 21:19
Maximum heat index 16.0 °C on day 22 at time 13:28

[NZ Thunderstorm Soc]

Total rainfall for July here in West Melton was only 46.9mm over 15 days.

JohnGaul
NZThS

[Chris Raine]

40.2 mm at Oamaru - South Hill over 8 days. No measurable rain since the thunderstorm on the 21st July.( 5mm + the hail that night)

[Nev]

Here's Niwa's long awaited preliminary Climate Summary for July 2009
(taken a while since it was released to the media last Sunday ).

National mean temp was 0.4°C below the July long-term average - third cool month in a row, although not as unusual as May or June.

Highest temp was 20.8°C at Rangiora on the 31st. Lowest temp was -11.7°C at Middlemarch on the 19th.

Of the six main centres, Auckland was the warmest and sunniest, Tauranga the wettest (also a little cloudier than normal, as was Wellington), and Christchurch the coldest and driest. Looks like they're back to the traditional sites this time except for Hamilton Aero rather than Ruakura.

I see they're referring to the Cromwell whirlwind/dust-devil as a tornado? Not to mention the 'mini-tornado' in Opunake, which, from what I've read, might just as easily have been a squall or down-burst?

[NZ Thunderstorm Soc]

It also records as Christchurch recording some lightning on the 22nd. I have no recollection of such but it did look thundery towards the Alps.

JohnGaul
NZThS