Global Precipitation & Temperature Outlook for December 2016

December 2, 2016

Overview
The December 2016 Outlook follows a pattern that has recurred for some time now: a temperature forecast that lights up with exceptional heat anomalies. This month, many parts of South Asia, East Asia, and Southeast Asia are forecast to be much warmer than normal. Not to be overlooked on the precipitation forecast map: significant dry anomalies are expected to envelope Sri Lanka. (For data sources see "About This Blog Post" below.)

Temperature Outlook
The dark red areas across southern Asia, shown on the temperature map below, indicate a forecast of exceptionally warmer temperatures in: much of Iran; western Afghanistan and eastern Afghanistan from, roughly, Kabul to Kandahar; much of Pakistan; Rajasthan, India; a vast northern belt across China from the Taklimakan Desert in the west reaching almost to the Yellow Sea in the east; and, southern Mongolia as well as a large pocket in western Mongolia.

Temperature outlook. Reds indicate above normal monthly average temperature. Blues indicate below normal monthly average temperature. The darker the color, the more extreme the anomaly relative to a 1950-2009 climatic baseline. Colors are based… — Temperature outlook. Reds indicate above normal monthly average temperature. Blues indicate below normal monthly average temperature. The darker the color, the more extreme the anomaly relative to a 1950-2009 climatic baseline. Colors are based on the expected return period of the anomalies.

Warm anomalies ranging from moderate to extreme are forecast for: Central Asia; China; Taiwan; much of India, particularly its southern tip; Sri Lanka; Myanmar; Southeast Asia; Malaysia; much of Indonesia; New Guinea; Mindanao, Philippines; and from Brisbane, Australia southward down the coast.

Central Saudi Arabia and parts of Yemen are also forecast to experience much warmer than normal temperatures.

In Africa, moderate to occasionally extreme warm anomalies are expected from West Africa south around the Gulf of Guinea; and on the other side of the continent in Somaliland and northern Somalia. Scattered warm anomalies are also forecast in southern Africa. A small pocket of cool anomalies is forecast in southwestern Ethiopia.

In the Western Hemisphere significant warm anomalies of varying severity are forecast for: eastern Ontario into western Quebec, Canada; the US Northeast; Florida; Cuba; Chiapas, Yucatan, and near Puerto Vallarta, Mexico; Guyana; Suriname; French Guiana; the Amazon Basin and northeast Brazil; and western Bolivia.

Precipitation Outlook
Looking closely at the precipitation map below, moderate to exceptional dry anomalies are forecast for Sri Lanka. Moderate dry anomalies are forecast for: Siberia, southern Iran, Saudi Arabia, Uganda, western Kenya, Tanzania, and Rio Grande do Sul, Brazil.

Precipitation outlook. Reds indicate below normal monthly total precipitation. Blues indicate above normal monthly total precipitation. The darker the color, the more extreme the anomaly relative to a 1950-2009 climatic baseline. Colors are based on… — Precipitation outlook. Reds indicate below normal monthly total precipitation. Blues indicate above normal monthly total precipitation. The darker the color, the more extreme the anomaly relative to a 1950-2009 climatic baseline. Colors are based on the expected return period of the anomalies.

Wet anomalies are forecast for: Kazakhstan, northern Mongolia, Myanmar, the Malaysian Peninsula, Western Australia, Cameroon, Equatorial Guinea, Gabon, and Venezuela. Wet anomalies may be extreme in western Myanmar, the Malaysian Peninsula, northern Kazakhstan, and southern Gabon.

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 December 2, 2016 which includes forecasts for December 2016 through August 2017 based on NOAA CFSv2 forecasts issued November 24 through November 30, 2016.

Technical details:

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.