Global Precipitation & Temperature Outlook for October 2017

3 October 2017

The October Outlook indicates warmer than normal temperatures forecast for a number of places in the world but Yemen stands out as exceptionally hotter, with conditions you'd expect to see once in 40 years. 

Precipitation Outlook
Much wetter than normal conditions are forecast for a vast stretch of China from southern Shandong on the coast into the interior through southern Henan and into Shaanxi. Similar conditions are expected in South America, roughly tracing the eastern ranges of the Andes from Bolivia through Peru, and southeast through much of northern Bolivia. Wet precipitation anomalies nearly as intense are forecast for Equatorial Guinea, Gabon, and El Salvador.

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.

Moderate to severe wet anomalies are expected in northern Xinjiang Province, China, into Almaty, Kazakhstan, and throughout Kyrgyzstan. Some moderate wet anomalies will reach from South Korea into southern Honshu, Japan. Primarily moderate wet anomalies are forecast for: much of Southeast Asia; Indonesia; Papua; western Australia and southeastern Queensland; Azerbaijan; pockets in the western Amazon Basin; and western Minnesota trailing into South Dakota.

A prominent path of severe to exceptional dry anomalies is predicted in the western Andes from coastal Ecuador down through southwest Bolivia. A small pocket of exceptional dry anomalies is forecast in eastern Central African Republic, with primarily moderate dry anomalies in the rest of the country and into Cameroon. Dry anomalies ranging from moderate to extreme are forecast for: the Ohio River Valley trailing south to the Gulf; in Russia from the Laptev Sea in the east down to the Sea of Okhotsk; and, the western Tibetan Plateau. Moderate dry anomalies are forecast for: the European Plain in Russia west of the Urals; northern Afghanistan; western Maharashtra, India; and Tasmania, Australia.

Temperature Outlook
Exceptionally warmer than normal temperatures are forecast for Yemen, the northern and eastern shores of the Persian Gulf, and a pocket in eastern Afghanistan, along with warm anomalies of varying intensity on the Arabian Peninsula, in much of Iran, and in southern India and Sri Lanka.

Warm anomalies reaching extreme or even exceptional severity are forecast in western Africa, around the Gulf of Guinea and south, into Central African Republic and northern Democratic Republic of the Congo. Severe warm anomalies are forecast for eastern Sudan, Eritrea, and parts of Ethiopia.

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.

Southeast Asia is expected to be much warmer than normal also, with extreme to exceptional anomalies radiating outward into Myanmar, Bangladesh, northeast India, Malaysia, Indonesia, and the Philippines. Likewise, intense warm anomalies are forecast for Taiwan, southeast China, and a vast swath of western China from Yunnan north. Warm anomalies of varying severity are forecast for much of Australia but may be more severe in Tasmania and across the north.

Severe warm anomalies are forecast for much of the Iberian Peninsula, and Northern Europe may be moderately warmer than normal. 

In the West, moderate to occasionally extreme warm anomalies are expected across northern and eastern Canada reaching into northern Michigan and the Northeast US, and in Brazil's eastern half. Isolated pockets of exceptional warm anomalies are forecast in: Nayarit, Mexico; southeastern Nicaragua; southern Peru; and western Bolivia near La Paz.

A few places are expected to be cooler than normal. Much cooler than normal temperatures are forecast for eastern South Sudan and northeastern Uttar Pradesh, India. Cool anomalies of lesser severity are forecast for northern Bolivia, eastern Kazakhstan, and central Khabarovsk Krai in eastern Russia.

Note on Administrative Boundaries
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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 October 2, 2017 which includes forecasts for October 2017 through June 2018 based on NOAA CFSv2 forecasts issued September 24 through September 30, 2017.

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.


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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