As discussed in the second part of this article, the 2020 NiMet predictions covered rainfall onset, cession, amount and length of the growing season. The predictions also covered temperature, dry spell, incidences of malaria, and cerebrospinal meningitis in the selected towns across the nation.
On the rainfall pattern in the country, generally, the 2020 seasonal year will be a near-normal rainfall with a pattern oscillating between warm and cold phases in most parts of the country.
Thus, a near-normal length of the season with above-normal rainfall to near-normal amounts will be experienced in 2020 across the nation.
However, NiMet quickly warned the public of the false onset of rainfall, “Before the full establishment of the onset of the planting season over the various ecological zones, a couple of rainfall events are expected to occur which could be enormous and tend to give a false start of the season. Such rainfall events are not uncommon, however, their frequency seems to be on the rise”.
Explicitly, NiMet made specific predictions for different places; the report indicated the 24th of February 2020 as the earliest (rainfall) onset date around the coast and the creeks of the south-south states.
This onset date from the coast is expected to change gradually and moving continuously northwards until the whole countries are covered with areas around Sokoto, Kebbi, Zamfara, Katsina, Jigawa, Yobe and Borno states likely to have their onset from the 2nd of June 2020.
This means that the country’s onset of rainfall dates will range between 24th February and 2nd June 2020. The prediction of 24th February is about two weeks earlier than 2019 prediction which stated: “The earliest onset is predicted to be around 7th March in the coastal and south-south towns”.
On the cessation of the 2020 rainy season, NiMet predicted the earliest cessation date to be 26th September 2020 beginning from towns around Katsina and the northern part of Sokoto.
Similar to rainfall onset, the cessation of rainfall will gradually move southward to cover the whole country by the date of 28th December 2020 over the Niger-Delta region.
Generally, Cessation dates in other parts of the North are expected to be in October through 5th November extending to 15th November in Gombe, Jos and Kaduna. In the Central and inland parts of the South, cessation dates are expected in November while the South-east, Lagos and the Niger-Delta are to have cessation dates in December.
Some places are predicted to have a normal cessation of rainfall season, while other places will have cessation earlier than normal and few others will have cessation slightly longer than normal. Places around Katsina, Jigawa, Plateau, Kogi and Ondo are predicted to have their rainfall cessations dates earlier than normal.
Reversely, some places in Osun state, parts of Lagos and Ekiti states are predicted to have their cessation at later dates than normal. The chances of occurrence of earlier and later cessation dates are relatively modest.
Part of the SRP made was the prediction for the length of the growing season or the rainy season in the year 2020. The rainy season period in days is predicted to vary from the minimum of 110 days to a maximum of 280 days.
About 110 days of the rainy season will be experienced at the towns within the boundary of Nigeria, Niger and Chad republics located in the northern part of the country. The towns in many places around the Atlantic Ocean in the south will receive rainfall within a period of 300 days in the year, 2020.
Thus, the predicted rainy season days span from 110 to 160 days in the Sahelian region of the north. As we progress southwards, the rainy season period increases from 160 to 200 days for some towns in Plateau, Niger and Adamawa states.
The inland cities of the south such as Enugu, Onisha, Ekiti, and Ibadan will expect a growing season between 210 and 280 days. The report notified farmers in Abuja, Kogi, and Makurdi to expect the length of the season within a range from 200 to 250 days.
The coastal areas are predicted to experience a long rainy season that may likely extend to 310 days. However, the growing pattern throughout the season is not expected to vary much from the normal across the country in recent years.
The variation expected in the length of growing season for the year 2020 is likely to affect a large section of the north-west where places like Sokoto, Kebbi, Gusau, Kaduna, Zaria and Kano are possibly going to experience an extended length of the growing season which may extend beyond 7 days.
In the central states, Abuja and Plateau could also experience an extended length of the growing season. However, Uyo in Akwa Ibom state reflects a slight reduction in length of the growing season but this signal will be quite insignificant and may not affect cropping season.
The rainfall amount in millimetres for several places as part of the 2020 SRP that NiMet presented to the public. The country is predicted to receive rainfall amounts ranging from 400 mm in the north to over 3000 mm in the south.
Places located in the extreme northern states of the country such as Sokoto, Katsina, Yobe and Borno are expected to have the least rainfall amounts within the range from 400 to 800 mm. Rainfall amounts in the range from 800 to 1200 mm have been predicted for places around Yelwa, Zaria, Dutse, Gombe and Yola.
The central cities comprising Abuja, Lafia, Jos, Benue and most southwestern states are expected to have between 1200 and 1600 mm. Places along the coastline of the country such as Delta, Port Harcourt, Benin, Calabar and Uyo are expected to have total rainfall amounts exceeding 2400 mm.
However, places around Shaki, Iseyin, Abeokuta and Katsina are expected to have below-normal rainfall. Reversely, above normal rainfall is expected in few places across the nation such as around Kebbi, Kaduna, Kano and Uyo.
Furthermore, the 2020 SRP contains “dry spell” prediction in selected towns across the nation. Dry spell is described as a situation when the rain ceases to occur over a short period of time in days after crops establishment and thus, causing the crops to wilt.
The term dry spell is commonly used by agriculturalists. The prediction shows that several states in the northeast and northwest will experience a dry spell of between ten and twenty-one days in the month of June.
The notable towns mentioned in the prediction to experience a dry spell in the month of June are Bauchi, Jigawa, Sokoto, Zamfara, Katsina, Kano, Kebbi, Yobe and Borno in the month of June. This may last 10 to 21 days after the onset spilling into July.
The moderate dry spell that may last 8 to 15 days is expected around Yelwa, Bida, Minna, Zaria, Funtua, Lafia, Bauchi, Abuja, Gombe and Yola in June 2020. In the year 2020, severe the effect of a dry spell is expected over the coast of Lagos, Ijebu Ode, Ibadan, Akure, Shaki, Iseyin, Ilorin and Ado Ekiti.
The length of days with relatively dry spells is expected to last between 10 to 25 days in places like Abeokuta, Osogbo, Shaki, Iseyin, and Ilorin with more than 50% chance of occurrence while the coast of Lagos, Ikeja, Ibadan, Ijebu Ode and Akure could have dry spells above 30 consecutive days in a worst-case scenario.
This is certainly a cause for concern and the farmers in the areas should prepare to mitigate the effects of the dry spell. The 2020 dry spell is likely to start as early as 18th of July in Abeokuta and as late as 4th of August along the coast of the southwest.
Temperature variation across the country was another parameter predicted by NiMet. The predictions for day and night temperatures were similarly presented. Alongside the temperature, predictions were predictions of incidences of Malaria and Meningitis in several towns across the nation.
On temperature prediction in 2020, greater parts of the country were generally predicted to experience warmer temperature in some months of the year 2020. What are the variations and increases in temperature in several towns? What are the implications for these predictions? What is the mitigation strategy for the farmers in the affected areas? To be concluded next week.
Professor Othman is the Executive Director of the National Agricultural Extension and Research Liaison Services (NAERLS), ABU Zaria.