Above average precipitation and rapid snowmelt highlight abundant water availability

• Afghanistan received above-average precipitation in March-April except in the northeastern region.

• Rapid depletion in the snow cover is displayed in all basins. While depleting snow water volumes in Khanabad, Khokcha-Ab-I-Rustaq and Panj in the northeast basins brings them to below-average, the snow water volumes in Arghandab, Ghazni and Helmand basins in the south have rapidly depleted to respective long-term average levels. The snow water volumes in the remaining basins in central, north and northwest regions are still above-average despite rapid depletion.

• The above-average rainfall and brisk snowpack depletion in basins with record level snow water volumes are expected to abundantly replenish country’s reservoirs. Sufficient water would be ensured to the irrigated wheat crop that will be attaining the critical flowering stage in May.

• The actual temperatures have been above-average in the first 10 days of April while being average to below-average through the end of April. Rapid depletion of snowpacks occurred due to above-average temperatures in early April. On the other hand, below average temperatures during latter half of April has led to sluggish growth of crops and may delay the harvest.

• The above-average temperatures expected in May-July are likely to provide the extra heat energy (growing degree days) necessary during the critical flowering, grain formation/hardening and harvest of standing crops.

Precipitation anomalies:

The cumulative precipitation from October 1, 2018 through April 25, 2019 expressed as percent of long-term average (1981-2010) indicates widespread above-average precipitation in all provinces (Figure 1). Seasonal cumulative precipitation remains at 145 percent or more across the country except in Badakhshan and Takhar (115 to 130 percent) in northeast; and 100 to 115 percent in Farah in the west. This has provided abundant water not only for healthy growth of winter wheat but also aided planting, emergence and vegetative growth of spring wheat in March to April.

Temperature anomalies:

The average daily temperature anomalies (⁰C) from long-term average (1961-1990) in early April indicate above-average temperatures that led to rapid snowmelt and sharp decline in snow water volumes.  However, during the latter half of April, the prevailing average to below-average temperatures may lead to sluggish growth and delayed harvest of standing crops.

Snowpack and snow water storage:

The relative changes in current snow depth differences between April 30 (top panel) and peak snow depth in mid-March (bottom panel) highlight the depleted snowpack (Figure 2). The visible change in snow cover between the two dates is typical in the season while above-average April rains may have accelerated the depletion of snowpack.

Figure 3 highlights rapid depletion of snow water volumes in Balkhab and Kabul basins as of April 30. In general, the rapid depletion of snowmelt in basins from record levels to average within a month is unique to this year. This brisk depletion may lead to healthy buildup of reservoir volumes and provide abundant water for the standing wheat crop and pastures in the country.

FORECASTS

Precipitation:

Cumulative precipitation forecasts for 7-day periods ending May 8 and May 15 are shown in the left and right panels of Figure 4 respectively. Dry conditions are expected to prevail in the next two weeks across the country except light rains over Nuristan and high elevation areas in Badakhshan provinces during the second week of the forecast.  

Temperature:

The North American Multi-Model Ensemble forecast of 2-meter air temperature anomalies for May - July (with April initial conditions) indicates 30 to 60 percent probability of above-average temperatures in the eastern region (Figure 5). The prevailing temperatures are expected to conclude snowmelt especially in the southwestern and northwestern basins in the coming weeks and expected above-average temperatures in May-July may provide additional heat units necessary for healthy grain filling/hardening of wheat in the country.