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Cook Islands Meteorological Service Early Action Rainfall Watch The Early Action Rainfall Watch provides sector managers with a brief summary of recent rainfall patterns, particularly drought and the rainfall outlook for the coming months. |
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Current El Niño-Southern Oscillation (ENSO) status: El Niño near its end. El Niño has ended and the El Niño–Southern Oscillation (ENSO) has returned to neutral. Climate models indicate ENSO will likely continue to be neutral until at least July 2024.
Cook Islands Meteorological Services along with regional climate partners will continue to closely monitor conditions in the tropical Pacific as well as model outlooks for further developments.
Status summary: No extremes were observed for all the Northern Cook Islands at the 1, 3, 6 and 12-month timescales. For the Southern Cooks, at the 1 month timescale, Palmerston experienced Very Dry conditions. The southern parts of Mangaia experienced Very wet conditions at the 3 month timescale. At the 6 month timescale, Palmerston experienced Seriously Dry conditions whilst the rest of the Southern Cooks experienced Very Dry conditions. Seriously Dry conditions continued for Palmerston at the 12 month timescale, whilst Aitutaki, Atiu, Mitiaro and Rarotonga experienced Very Dry conditions.
Outlook summary:
For May, a Very high chance of Very Wet conditions for Suwarrow, Nassau, Manihiki and Rakahanga. A High chance of Very Wet conditions for Pukapuka and Penrhyn.
In the Southern Cook Islands, there is a medium chance of Very Dry conditions for Atiu and Takutea. No extremes expected for the rest of the group.
For May to July 2024, there’s a Very high chance of Very Wet conditions for Nassau, Pukapuka and Manihiki. A High chance of Very Wet conditions for Suwarrow, Rakahanga and Penrhyn.
There is a Medium chance of Very Dry conditions for Aitutaki, Manuae, Takutea, Nga-Pu-Toru and Rarotonga.
Impacts
After the specified period of below or above average rainfall, the following primary agricultural and hydrological variables and secondary socio-economic and health variables may be impacted. Note the periods are estimates only. Allow for uncertainty associated with island size, topography, and geology and soil type. Contact the relevant sector offices for further information on impacts.
Rainfall monitoring for 12-month, 6-month, 3-month and the past month
About Rainfall Monitoring
The Standardized Precipitation Index (SPI) is used to assess rainfall status from the MSWEP dataset. MSWEP is a global precipitation product that combines rain gauges, satellite and reanalysis data to a 0.1° resolution. Meteorological Drought is defined as drought assessed by rainfall data only. A site is assigned 'No Alert' when rainfall has been near normal for the period(s) in question. The 3-, 6- and 12-month timescales can accurately predict drought, whereas 1-month status is an approximation only. This is because it is difficult to assess drought at this timescale.
Extreme Rainfall Outlooks
Rainfall Outlooks for May 2024, and May to July 2024
About Rainfall Outlook
Seasonal outlooks have been produced using the Australian Bureau of Meteorology ACCESS-S model http://www.bom.gov.au/climate/ahead/about/model/access.shtml. The outlook provides an indication of total one and three-month rainfall, not how intense the rain may be in any one event, nor how it may vary within the three months. A station is assigned 'No Alert' when near normal rainfall is favoured or there are equal chances of below normal, normal and above normal rainfall.
Contact the Cook Islands Meteorological Service for further information
The Director, Cook Islands Meteorological Service
P.O Box 127, Rarotonga, Cook Islands, Phone: 682 20603,
Website: http://www.met.gov.ck Email: mot.weather@cookislands.gov.ck
