Tuesday, September 24, 2024

Powerful anticyclone to give way to lows

philip-duncan-1-tall
By the rumbling tummy of Phil Duncan’s cat, the seasons are changing and properly neutral, chaotic weather is on the way.
Reading Time: 2 minutes

Have you noticed the little bit of extra sunlight each day lately? If your answer is no then give it another week or two and you’ll see it. The evenings are perhaps most noticeable for the later and later sunset. 

If you’re anything like my extended family, 5pm is time to watch The Chase – and the skies seem to be getting brighter and brighter as that show starts, especially for those of us in the north of New Zealand. 

My cat is also laying off with the aggressive meowing around feeding time. She has an incredible gift at showing up in my home office bang on the dot of 5pm with a “feed me” meow. But the past week or so she’s not so sure of her schedule as the days get a little longer. (Sorry for my deeply scientific technical speak).

The record challenging high pressure zone that dominated New Zealand’s weather last week gave many of us the ideal conditions to notice such fine details as sunrise and sunset times. But the weather this week, for the second week of the school holidays, will see low pressure return to NZ. 

I’ll go back to our ClimateWatch headline in April once El Niño was over, which basically said we’re in neutral and anything can happen. That sure is coming true with cold blasts, warmer than average days, snow for the skifields of both islands, fog, frosts, drier than average, and some locally wetter than average, areas. Variety is with us right now and may continue to be for months ahead.

Turning to July rainfall and soil moisture deficits: usually once winter has arrived farmers, especially dairy farmers, don’t usually want a lot of rain to make mud – and it’s too cold for the grass to grow anyway. But we’re now in that place where more rain, so long as  it’s falling in the right places, will be welcome so that spring doesn’t kick off too dry (and spring is only six weeks or so away now!) 

The region with the largest soil moisture deficit right now is Canterbury. In second place would be the southwestern corner of the North Island, so Whanganui to Manawatū.  

Remarkably, both NZ and the entire southern half of Australia are sharing the same pattern right now, where one big high rolls through bringing dry, followed by a low pressure zone and some rain. 

This pattern seems to be giving some regions in both nations repetitive rain that’s become annoying for some, while others keep being in the “miss” part of “hit and miss”, and remain in a rain shadow (much like Canterbury has in NZ, or the lower western North Island).

Despite rain coming back into the forecast, some areas may continue to be in the rain shadow – and those getting too much rain may get more. Some long-range data suggests as more lows cross NZ for the remainder of July, the eastern North Island may get more unwanted heavy rain while the eastern South Island again misses out. 

NZ’s neutral and chaotic weather pattern carries on.

Total
0
Shares
People are also reading