Hang on farmers, rain is coming
FRIDAY FEBRUARY 22, 2013
This summer has been hot and dry and farms are beginning to feel it, although many have actually had occasional periods of rain. In January Auckland only had 4 light rain days, but Wellington had 10 rain days, with over 60mm falling in the 4 days between 14th-18th, 26mm of that falling during one day.
Although Christchurch had a mere 6 rain days throughout January, in the three days between 15th-18th no less than 27mm fell. Dunedin had 17 rain days in January. Even Napier received rain on 6 days.
Although summer rain has been of some intermittent relief it has not been enough to maintain healthy pasture, especially with the high temperatures. In the first week of February many places e.g. Waikato, HawkesBay and the lower half of the North Island received predicted rain, but since then moisture has been sparse.
So the question being asked is whether or not a lingering drought is imminent. The answer is no.
What we have been missing most is the cyclonic rain. The cyclone season, which brings large quantities of Pacific rain accompanied by dying but still powerful air flows was always going to be a fizzer this time around for both Australia and NZ. Some Australians are only now getting the thunderstorms they usually expect before Xmas.
Our Weather Almanac for NZ, 2013 lists March as the month remnants of cyclones should start affecting us. Three forthcoming wet systems, two of them ex-cyclonic, are worthy of mention. The first system, not a cyclone, comes in the first week in March from across the Tasman Sea beneath the Bight, bringing substantial rain amounts.
This should most benefit districts in the lower half of the North Island and the top half of the South island and on the east side of the South Island. It means chances in the first week of March for good rain for Northland, Auckland, central and lower North Island, Marlborough, Nelson, a bit in Hawkes Bay but not a lot, the top of the South Island, the West Coast, and Canterbury. There may be localised flooding in Blenheim.
Update: the rain came but was not substantial
Then in the second week of March the first descending cyclonic system makes its dying presence felt. Because of new moon kingtides around this time swelling rivers there could be localised flooding. Update: there is a tropical low descending from the north now (9 March). It formed as expected and remains to be seen which way it goes. But here's what the Australian metservices are predicting
The NZ metservices seem to concur:
This means we have been on target, because this article was written back in February. Even if the rain doesn't eventuate, the potential was clearly there. Either rain will come or the three of us, that's the Aussie mets, the NZ mets and us, all take a dive on this one. That is not likely.
The success of this prediction also bodes well for our best-rain-of-the-month date. We have always been claiming that remnants from a second cyclonic system should bring good rain for just about everyone after the 20th. This was always going to be the main drought-breaker. See almanac p27 and 29.
may miss out on much of it, and they may not receive good falls until the second and third weeks in April. Most districts may have a wet April, especially Tauranga, with all months expected to be wetter than average except Otago and Southland.
We can look at each region for March starting from the top. Northland and Auckland including Whangaparoa get good falls in first half of March with local flooding possible in some areas in the third week, then heavy falls in the fourth week about 20th-27th. Dargaville’s rain is in the first and fourth weeks. The far north gets most rain amounts 20th onwards. Kaikohe and Whangarei get heavy falls around 14th and 22nd. Coromandel may be wet enough to bring flooding.
may get rain throughout the first week, at the end of the second week, then the beginning of the fourth week and over the last 9 days of the month. The heaviest falls may be around 5th, 13th, and 22nd.
can expect about 11 rain days in March, with the driest spell 15th-19th, and then lots of rain around 22nd. Katikati may be very wet at times. Kawerau is wet in the first 9 days and around 22nd. East Cape’s rain is mostly around the 8th and 20th-23rd.
Taranaki/Central Plateau/King Country are looking at a wet March with about 16 rain days. Much rain is expected with chances of flooding in the first week, then around the midmonth, then from the 22nd onwards.
gets some rain in the first week of March and then the start of the fourth week, but the rest of March is dry, with no more than 5 rain days expected for the month and no large falls for Gisborne. Napier could get a 30C day in the fourth week. Good rain is coming up in April and Waipukurau farmers could get all the rain they need from 8 April onwards..
Rangitikei is wet around 2nd and 16th. The lower NI has a wet March, especially around 2nd and 26th. Martinborough’s rain is around 6th and 22nd. Marlborough sees about 8 rain days during March, but with some large amounts – chance of heavy falls 3rd-6th and then 20th-24th..
Nelson and Motueka have chances of flooding in the first and fourth weeks of March, and around the endApril/beginning of May.
sees plenty of rain through March, with about 12 rain days, but they should be mainly light falls except for odd heavy dumps around 4th (especially Hanmer) and 20th. Kaikoura’s rain is mostly in the first week. South Canterbury can expect rain 9th-11th and after 20th. The Rakaia river levels may swell after 12th. Fairlie rain is sparse in March and the hydrolakes dry until 20th.
For Otago about 7 rain days are expected, with dry conditions during most of the first 20 days of March. Alexandra and Ranfurly should not expect large amounts of rain in any month before October. Balclutha, Dunedin and Cromwell’s rain is mainly between 20 March-4 April. Queenstown may flood after the 20th.
Southland gets some rain in the second week but it may be continually wet after the 20th, and on the West Coast, March should be dry 6th-18th but all rest of the month should be wet.