The Nigerian Meteorological Agency (NiMet) has produced the 2016 edition of the Seasonal Rainfall Prediction (SRP) in fulfilment its mandates of effectively monitoring the weather and climate of Nigeria, provision of relevant meteorological information, advisories and early warning services to the various weather-sensitive sectors of the Nigerian economy. This prediction constitutes a decision support tool for Nigerians, as it provides critical information to enhance informed decisions, especially for planners, policy makers, and operators of the various rainfall-sensitive sectors of the economy.
Such sectors include agriculture, water resources management, environment monitoring, health, disaster management and a host of other weather-sensitive sectors.
The input data for the production of the SRP include temperature, rainfall, ENSO phase, phenological data, soil information and farming practices (among others), while the outputs comprise the following critical information:
- Day and night temperature forecast. These define expected comfort level during the first four months of the year
- Onset and cessation dates of the growing season
- Length of the season
- Annual amount of rainfall
- The little dry season and the dry-spell in May –July
- Malaria incidence forecast
- Socio-economic implications
On the completion of the SRP early in the year, it is first presented to major stakeholders for their inputs, specifically to the socio-economic implications section before its presentation to the general public. The stakeholders cut across operators in the agricultural sector, water resources, dam and river managers, health, energy, disaster managers, researchers and the academia. It is thereafter released to the public in order to provide sufficient lead-time for its incorporation into decision-making processes of the various users such as policy makers, planners, farmers, water resources experts and hydropower generators.
The prediction model, as in other years, is based the strong tele-connection between the El-Nino Southern Oscillation (ENSO), Sea Surface Temperature (SST) anomalies and the rain-bearing weather systems in Nigeria. The 2016 SRP is based on the predicted persistence of the current strong El-Nino phase into the second quarter of the year.
The ENSO projections for 2016 pointto a strong El-Nino threshold in the first quarter of 2016 weakening to about 60 percent through April to June, and gradually moving to a neutral phase after August. Based on this scenario, the 2016 rainfall regime in Nigeria is likely to be predominantly under the influence of an El-Nino condition for most parts of the year. NiMet will issue an update on this if a major change is observed.
The 2016 SRP includes the evaluation of the performance of the 2015 prediction to ascertain the performance by comparing the predicted with observed values in different parts of the country, rated in terms of skills (%) as good forecast or forecast out where the forecast did not perform well. The result of the evaluation is used to modify the model for the subsequent years. In 2015, temperature predictions performance for the day and night ranged from 82-100 percent.
The length of the season achieved 87% skill while the annual amount reached 84% performance. The forecasts were mostly out in the Sokoto area for the rainfall components, and this is being corrected in the 2016 predictions.
The highlights of the 2016 predictions include:
- Moderate –severe harmattan season during January and February
- Warmer-than-normal conditions during February and April across the country and a warmer South in March.
- Late onset of the growing season in the Delta, the far northwest and northeast and early onset over the central areas and inland of the South.
- Early cessation of the rains in parts of the northwest and prolonged rainy season over the inland of the southwest, Delta State and Akwa Ibom. Shorter length of season is generally predicted for 2016
- Rainfall is predicted to be above normal in parts of the northwest, Niger State, inland of the southwest and the Delta region. Below-normal rainfall is projected over Yobe, Gombe, Taraba, Kogi, and Benue States and down to the South of the country.
- Prospects of serious short-period heavy rainfall events during the peak of the rainy season (July-September) in some parts of the South and central States, despite the probabilistic rainfall projections, given the heavy rainfall characteristics of the areas.
- A moderate Little Dry Season in July and August is predicted, while dry-spells (consecutive days of about 10days or more without rainfall) are predicted to occur in the central States in May and northern States in June/July.
- For the malaria forecast, while the mosquito bites index is high in most parts of the country, the malaria severity index is predicted to be relatively moderate during May- August (in the central States), becoming low in the other months.
- Socio-economic Implications.
The socio-economic implications of the 2016 SRP for the various key sectors, along with some relevant advisories are summarized below:
– The predicted late onset of the rains in and around Sokoto, Zamfara, Kaduna, Borno and Adamawa will create water stress during the beginning of the cropping season. The use of irrigation is advised. Warmer-than-normal temperatures projected in February and April for several parts of the country will negatively affect livestock, fish farming and water availability for animals. Vaccination is advised to help the animals withstand the associated health challenges.
–the predicted moderate harmattan is expected to affect air travel with lots of delays and cancellations especially during January and February. The inland water transport is likely to be challenged due to shallow water in the rivers caused by below
-normal rainfall predicted for Yobe, Gombe, Taraba, Kogi, and Benue States. Daily weather forecasts by NiMet as well as short range weather outlooks will help operators manage the situation.
- Dam and other river flow monitoring, operators are advised that the predicted
above-normal rainfall in some parts will enhance their activities. However, caution should be exercised to reduce the negative impact of sudden release of excess accumulated waters from the dams.
- Health sector
The predicted warmer conditions may translate to hotter days and nights particularly in April when maximum day temperatures reach 40 –44oC in the North and central States. The minimum temperature may reach 37oC in Yola and Kebbi States. The frequency of heat-related ailments may also attain very high proportions. Aggressive enlightenment and vaccination programmes should therefore be embarked upon on the release of this forecast.
- Disaster risk preparedness
All the challenges listed above constitute issues for disaster risk preparedness. The warmer-than-normal conditions predicted bring drier-than-normal conditions and this creates required condition for the incidence of bush, domestic and industrial fires across the country. Citizens are advised to be careful handling highly inflammable materials and always switch off their electrical appliances when there are power fluctuations and when they are absent from home.
Culled from Nigerian Metrological Agency’s website www.nimet.gov.ng