Seasonal forecast and implications for the October 2016 – May 2017 wet season

Seasonal forecast models indicate a likelihood for average to below-average precipitation across much of Afghanistan during the 2016/17 wet season (October – May), with above-average temperatures prevailing. Close monitoring of the volume of the snowpack and water levels in rivers is necessary in all regions during the upcoming wet season to understand whether there will be sufficient water available for irrigation. Similarly, spring rainfall must be monitored closely, as deficits could adversely affect rainfed wheat production between March and May 2017.

• In Afghanistan the main rain and snow season, or wet season, begins in October with relatively low accumulations, and gradually increases over the following months before tapering off in late April and May. In general, the peak of the wet season is during the beginning of the year, from January through April. Due to the mountainous terrain and prevailing weather patterns in the region, there is a significant degree of variability in seasonal accumulations of snow and rain.
• Wheat, by far the dominant staple crop in the country in terms of both production and consumption, is sown mostly in the autumn in areas irrigated by snowmelt, whereas in rain-fed areas it is sown primarily in the spring. The main harvests vary by elevation and location, and range from May to August, or even later in the highest elevation areas.
• A poor spring rainfall season has the potential for significant adverse impact on the planting and development of rain-fed wheat and other crops. While below-average snowpack can also adversely affect irrigated wheat production, the likely or potential impact of this on aggregate irrigated production is much less severe. As indicated in Figure 1, the year-to-year variability for rainfed wheat production is much greater than that for irrigated production.

• There is a clear link between sea surface temperatures (SSTs) in the Pacific Ocean and the likelihood of different seasonal outcomes during the wet season in Afghanistan. Currently, SSTs in the east-central equatorial region of the Pacific Ocean are anomalously cool, and have a possibility of reaching the defined threshold for La Niña. Regardless of whether this occurs, these cool temperatures coupled with significantly warmer than average SSTs in the western Pacific provide a temperature gradient that increases the likelihood for below-average cumulative precipitation during the coming wet season.
• Seasonal forecast models indicate a likelihood for average to below-average precipitation in Afghanistan during the beginning of the wet season from November through January (Figure 3). During the months that typically bring the greatest cumulative precipitation, from February through April, there remains an elevated probability for below-average precipitation in southern and eastern Afghanistan. In the north, models indicate above-average precipitation (Figure 5).
• In recent decades, temperatures in Afghanistan have generally been above the long-term average, due to climate change and global warming. However, forecast models indicate a likelihood for temperatures during the coming wet season to be particularly high and above those of last year (Figures 4 and 6).
• Since 2000, years with La Niña or similar SST conditions in the Pacific Ocean have been associated with below-average vegetation conditions during the spring in Afghanistan (Figure 7). However, due to the variability of weather patterns in the region, there remains a large spread of possible seasonal outcomes for Afghanistan between November 2016 and May 2017. Nevertheless, the most likely scenario is for average to below-average rainfall and snowfall in most areas during the coming wet season. FEWS NET will continue to monitor and provide updates during the season. 

• Close monitoring of the volume of the snowpack and water levels in rivers is necessary in all regions during the upcoming wet season to understand whether there will be sufficient water available for irrigation. Similarly, spring rainfall must be monitored closely, as deficits could adversely affect rainfed wheat production between March and May 2017.
• Land surface temperatures and snowmelt should also be monitored as the expected above-average temperatures may increase the risk of spring flooding in some areas, as snow may melt more quickly than usual, particularly at lower elevations.