WSIM Precipitation Forecast for May 2015 based on NCEP CFSv2 forecasts issued 4/15/2015-4/21/2015

Precipitation outlook for May 2015 based on an ensemble of 28 NOAA CFSv2 seasonal forecasts issued April 15-21, 2015. Blues indicate more precipitation than usual, reds less precipitation than usual. Units are in “return period” (the inverse of the probability of seeing an anomaly of that magnitude or worse).

Recent observed accumulated precipitation for northern Pakistan region. Data source: CPC (Gauge-based) Unified Precipitation (Climatology 1981-2010) (updated on 21 April 2015)

Recent observed accumulated precipitation for northern Pakistan region. Data source: CPC (Gauge-based) Unified Precipitation (Climatology 1981-2010) (updated on 21 April 2015)

  • First, we want to draw your attention to western India and Pakistan.  Note that we are forecasting surpluses with return periods with >10 years period.  This is on top of well above normal precipitation in March and April (see graph at right) that has led to spotty flooding in the region.  As a result, the soil is already saturated.  If these rains do materialize as forecast, there is potential for wider area flooding.  The monsoon typically arrives in this region in June/July.  Even a normal monsoon on top of this prior saturation can be problematic.
  • The surplus in Brazil is expected to expand northward across the central portion of the country and increase in size and intensity from the April 2015 forecast.
  • We see an emerging deficit in Venezuela and nearby countries consistent with our composite seasonal forecasts in April 2015.
  • Deficits in southeast Asia, the Phillipines, and Papua/Papua New Guinea.

This blog post presents results from our "WSIM Precipitation and Temperature Forecasts" report issued on April 23, 2015. This report current includes forecasts for May 2015 through January 2016 based on NOAA's CFSv2 forecasts issued April 15 - 21, 2015.


Many analyses reported in ISciences-authored blog posts are based on data generated by the ISciences Water Security Indicator Model (WSIM). Other sources, if used, are referenced in footnotes accompanying individual posts. WSIM is a validated capability that produces monthly reports on current and forecast global freshwater surpluses and deficits with lead times of 1-9 months at 0.5°x0.5° resolution. This capability has been in continuous operation since April 2011 and has proven to provide reliable forecasts of emerging water security concerns in that time-frame. WSIM has the ability to assess the impacts of water anomalies on people, agriculture, and electricity generation. Detailed data, customized visualizations, and reports are available for purchase.

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