The Outlook for May 2016 includes the forecast of exceptional precipitation in the eastern portion of Venezuela's Orinoco watershed. Much hotter than average temperatures are forecast to dominate much of Southeast Asia and Indonesia, along with many other parts of the world.
The presence of darker blues on the map in eastern Venezuela indicates a forecast of extreme to exceptional precipitation - what would be expected to occur once in 20 to 40 years or more. Likewise, in Africa blues of the same shades run through Ethiopia down into northern Kenya; and from northern Zambia into Democratic Republic of the Congo and Tanzania.
Much of northern India, eastern Pakistan, northern Afghanistan, and western Uzbekistan are forecast to experience above normal precipitation. Surplus precipitation anomalies are also forecast in May for the Yangtze and Yellow River Basins in China.
Drier than normal conditions are forecast for: Bhutan, Myanmar, western Thailand, South Africa, northeastern Brazil, and parts of Peru.
The darkest red areas on the temperature map below indicate a forecast of exceptionally hotter temperatures. Widespread exceptional anomalies are particularly noticeable across Southeast Asia, Malaysia, Indonesia, the Philippines, and Papua New Guinea. Places far from each other - such as Alaska and South Island, New Zealand - share a May forecast that is much hotter than normal. Many other parts of the world are also forecast to be exceptionally hotter, including: eastern Nicaragua, San Jose, Panama; along the Pacific Coast of South America and in central Brazil; the western Sahel and the Arabian Peninsula; Gujarat, India; and Brisbane, Australia.
Elsewhere the predominance of yellows and oranges indicates widespread warm anomalies of lesser severity, while a few bright blue spots - South Sudan and southern Democratic Republic of the Congo - stand out with cool anomalies forecast.
About this blog post:
Each week, ISciences processes an ensemble of 28 seasonal temperature and precipitation forecasts issued by the National Oceanic and Atmospheric Administration's Climate Forecast System Version 2 (CFSv2). We present our results in a proprietary weekly report titled Global Water Monitor and Forecast: Precipitation and Temperature Outlook. This blog post summarizes our Outlook released May 2, 2016 which includes forecasts for May 2016 through January 2017 based on NOAA CFSv2 forecasts issued April 24 through April 30, 2016.
- Each CFSv2 forecast is bias corrected by:
- Constructing probability density functions from CFSv2 hindcasts.
- Fitting the hindcast probability distribution functions to a generalized extreme value distribution.
- Using an inverse lookup to an extreme value distribution fitted to the observed temperature and precipitation record (Fan & van den Dool 2008, Chen et al. 2002).
- The map colors depict the return period of the median forecast anomaly.
- Regions where the interquartile range of the ensemble spans both above normal and below normal conditions are hashed as having uncertain direction.
- Regions where the interquartile range of the ensemble divided by the median forecast is large (>0.4) are hashed as having uncertain magnitude.
- Results are reported in terms of return period using a 1950-2009 baseline.
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