Global Precipitation & Temperature Outlook for June 2017

2 June 2017

Overview
Exceptionally warmer than normal temperatures are forecast for a number of places in June but may be particularly widespread across northern South America and across the Sahel in Africa. Gabon will be much wetter than normal and Western Australia is expected to be much drier.

Precipitation Outlook
In Africa, as noted above, Gabon is forecast to be exceptionally wetter than normal and wet precipitation anomalies will reach into the surrounding countries of Equatorial Guinea, Cameroon, and Republic of the Congo, though of lesser intensity. A band of moderate to exceptional wet anomalies is expected across the middle of Democratic Republic of the Congo. Wet anomalies of similar intensity are also forecast for eastern Zambia into central Tanzania. Large pockets of severe to exceptional dry anomalies are forecast for Ethiopia, particularly in the west. Eastern Somaliland is expected to be moderately drier than normal. Moderate to severe dry anomalies are forecast for northeastern and central Kenya.

A wide expanse of dry anomalies is apparent in much of Australia's western half. Moderate dry anomalies are predicted for much of the southern portion of Western Australia, but exceptional anomalies are expected surrounding Perth with severe to extreme anomalies radiating outward. Extreme wet anomalies are forecast for Northern Territory's Top End, the northernmost region of the Territory.

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.

Scanning the map for other large patches of color indicating widespread anomalies, the southern United States jumps out in blues and greens. Moderate to extreme wet anomalies are forecast for a vast swath from Texas through Florida, which may be most intense in eastern Texas, Louisiana, and southern Mississippi. Primarily moderate dry anomalies are forecast for northern California and Washington. 

Also noticeable, in Russia a large area of wet anomalies ranging from moderate to extreme is forecast for the eastern Volga River basin northeast of Kazakhstan. A vast expanse of dry anomalies is forecast in the Central Siberian Plateau.

Wet anomalies of varying intensity are forecast in: Ireland; Scotland; western Myanmar; southeast China; eastern Borneo; Sulawesi; and New Guinea. 

Dry anomalies of note - moderate to extreme - are forecast in a relatively small pocket of northeastern Brazil in Pará and Maranhão. Dry anomalies are also expected in Roraima, Brazil. 

Extreme to severe dry anomalies are forecast for Bhutan, and dry anomalies of varying severity are forecast for northern Thailand, northwest Laos, and central Vietnam.

Temperature Outlook
Many regions on the temperature map below pop out with large areas of red and dark red, indicating extreme to exceptional warm anomalies. These include: much of northern South America; the Sahel in Africa; much of coastal West Africa; Somaliland and parts of northern Somalia; southeast Kenya; Madagascar; southern Saudi Arabia; Yemen; eastern Oman; south/central Iran; Sumatra; northern Laos; and a large pocket in Russia's Central Siberian Plateau. 

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.

Severe to extreme warm anomalies are forecast for Southeast Asia, Malaysia, Indonesia, the Philippines, Papua New Guinea, southern China, Inner Mongolia, Mongolia, and South Africa. 

Warm anomalies of varying severity are expected in many parts of Europe; across southern Africa; southern India and Sri Lanka; southwest Western Australia, eastern Queensland, and Tasmania; the western US and southern Florida; southern Nunavut and northeastern Canada; central Mexico, Chiapas, and Yucatan; Guatemala; Belize; El Salvador; Honduras; and western Cuba. 

Cool anomalies are forecast for pockets of Democratic Republic of the Congo, central Australia, and eastern European Russia.

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 June 2, 2017 which includes forecasts for June 2017 through February 2018 based on NOAA CFSv2 forecasts issued May 25 through May 31, 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.

Comment

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.

For more information contact info@isciences.com.

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