Gisborne and northern Hawke's Bay mainly recorded around 100mm during the cyclone, with higher elevations picking up in excess of 200mm.
Northwesterly winds and a troughy Tasman Sea returned, bringing further rainfall to western regions of both islands, and Nelson. Elsewhere, precipitation was patchy and not overly substantial.
Importantly, the drought regions continued fairly dry during March. Rainfall was patchy for Otago and Canterbury (10mm-40mm), and generally below normal for coastal Marlborough, Wellington and southern Wairarapa.
Based on soil moisture deficit levels in late March, rain received in the driest regions was insufficient to break the drought. The soils remained in significant deficit across most of Marlborough, Canterbury and Otago, and around Wellington and Wairarapa. Soil moisture levels remained low in the Waikato and greater Bay of Plenty regions.
North Island regions (excluding Gisborne) and for north and eastern South Island, another solid top-up of rain is essential as we move through April, to allow soil moistures, and farm systems, to recover.
Things to watch in the tropics
There's been unusual conditions in the tropical Pacific, with several tropical cyclones (Pam, Bavi, Nathan) strongly influencing some of the El Nino indicators we monitor.
The Southern Oscillation Index (SOI), which is a measure of pressure between Darwin and Tahiti, has been bouncing around short-term, typical when the tropics get active. Cyclone Pam cooled off sea surface temperatures along her track, but that's expected to be short-lived.
Cyclone Pam produced one of the strongest reversals of the trade winds (normally easterly) in the western tropical Pacific seen in recent years. The westerly wind associated with Pam is expected to increase the already warm below-surface sea temperatures in the tropical Pacific Ocean, and may have long-term implications. Previous westerly wind bursts have served as a forerunner to El Nino development.
Although this time of year is when computer models of El Nino Southern Oscillation (ENSO) are least reliable, international climate models took notice of the recent westerly winds, and strengthened their view on El Nino development by the southern winter.
How is April looking?
Early to mid April is when the weather starts to change, with rainfall increasing, and temperatures dropping. Weather systems typically get mobile, and the weather can be changeable. Early April looks reasonably standard for the time of year. The highs look to be centred to the north of the country, with a westerly regime over New Zealand.
Expect mobile rain bands embedded in the westerly flow, and these should bring intermittent rainfall to western regions. However, rainfall isn't likely to be substantial for eastern areas.
The west of the North Island should receive near-normal rainfall, while western parts of the South Island look to receive normal to above normal precipitation.
Temperatures in the first half of the month are forecast to be above average for the time of year.
Get the latest MetService four-week outlook at www.metservice.com/rural/seasonal-outlook
