Global Precipitation & Temperature Outlook April 2019

3 April 2018

OVERVIEW
The April Outlook indicates a forecast of warmer than normal temperatures in many parts of the world, and regions with especially widespread or intense anomalies include Siberia, Alaska, Thailand, Sri Lanka, around the Gulf of Guinea in Africa, and through much of the Andes in South America. Areas forecast to be wetter than normal include northern Africa and pockets of the Middle East.

PRECIPITATION OUTLOOK
Central and northern Algeria, Tunisia, and much of Libya will be wetter than normal. Moderate to severe dry anomalies are expected in parts of east Africa including southern South Sudan, southern Ethiopia, southern Somalia, much of Kenya, Uganda, Rwanda, Burundi, northwestern Tanzania, and southern and northeastern Democratic Republic of the Congo (DRC). Anomalies could reach exceptional intensity in small pockets of northeastern DRC. Republic of the Congo will be moderately drier than normal, with more intense conditions in the northeast. Moderate dry anomalies are also forecast for eastern Angola, southern Zambia, Zimbabwe, northern Botswana, and pockets in northern Mozambique. Further south, Swaziland and surrounding regions of South Africa are expected to be moderately wetter than normal.

Primarily moderate wet anomalies are forecast for southern Turkey, northern Syria, Iraq, Kuwait, from Riyadh to the Red Sea in Saudi Arabia, western Iranian provinces including Khuzestan, and along Iran’s Caspian Sea coast. Anomalies may be severe surrounding Basra, Iraq and southeast of Baghdad into Lorestan Province, Iran.

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.

In Europe, moderate dry anomalies are forecast for France, Germany, northeastern Poland, Belarus, Lithuania, and Finland, but anomalies may be severe in France from Dijon to Nancy in the east and from Paris to Orleans in central France. Conditions in Russia will be somewhat drier than normal from, roughly, Nizhny Novgorad in the Middle Volga region eastward past the Ural Mountains; and, somewhat wetter than normal in the Central Siberian Plateau.

Moderate wet anomalies are expected along the Caspian Sea in Kazakhstan’s western province of Mangystau; in northern Afghanistan from Mazar-e-Sharif south to the Harirud River, and east of Kabul; and northern Pakistan from Peshawar past Islamabad to Lahore; and nearby in Punjab, India. Some moderate dry anomalies will dapple through India’s southern half and will cover most of Sri Lanka. Bangladesh will be wetter than normal with moderate to extreme anomalies reaching into nearby regions of Far East India and into northern Myanmar.

In East Asia, moderate dry anomalies are forecast for northern Mongolia, moderate to severe dry anomalies in South Korea, and moderate to severe wet anomalies in China’s central Tibetan Plateau and south of the Yangtze River in Zheijiang and Jiangxi in the east.

Western Thailand is forecast to be moderately drier than normal, with generally mild dry anomalies elsewhere in Southeast Asia. Some pockets of dry anomalies are expected in the Philippines, on New Guinea, and scattered across eastern Australia. Wet anomalies are forecast along part of Australia’s northern coast near Darwin.

In South America, moderate to extreme dry anomalies are forecast from eastern Venezuela through French Guiana and into Amapá, Brazil. Northern Amazonas will see conditions slightly less intense between the Rio Negro and Rio Unini. Northeastern Brazil will be wetter than normal, with anomalies ranging from moderate to severe in Maranhão, and northern Piauí and Ceará. Wet anomalies are forecast in central Bolivia from La Paz to Sucre. In Central America and the Caribbean, Panama will be somewhat drier than normal and Cuba will be wetter than normal. Further north in Mexico, moderate dry anomalies are forecast for the western states of Michoacán, Mexico, Morelos, and Guerrero, and also in southern Veracruz and Tabasco.

In the U.S., Alaska is expected to be drier than normal. Wet anomalies are forecast in the Pacific Northwest, northern California, the northern U.S. Rocky Mountains, and in southwestern Texas.

TEMPERATURE OUTLOOK
The temperature map lights up with many areas forecast to experience much warmer than normal temperatures. Most notable is the vast stretch across nearly all of Russia indicating warm anomalies for the entire country and extreme to exceptional anomalies in Siberia. Warm anomalous conditions of varying intensity extend into Scandinavia and include extreme anomalies in Lapland. The Baltics will be moderately warmer than normal, as will Denmark, Netherlands, Switzerland, southern France, Romania, Albania, southern Italy, Scotland, and Ireland.

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 t… — 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.

In Africa, warm anomalies of varying intensity are forecast across the center of the continent in a broad band from Gambia in the east to Somalia in the Horn, and extending from the Sahel through central DRC. Anomalies will be exceptional in coastal areas from Gambia, around the Gulf of Guinea, Cameroon, Equatorial Guinea, Gabon; and, Republic of the Congo, northern DRC, Djibouti, Somaliland, southern Somalia, and surrounding Nairobi (Kenya), Warm anomalies are also forecast in the southern nations of Namibia, Botswana, South Africa, Zimbabwe, and northern Madagascar. Anomalies will be exceptional in the Kalahari Desert and in northeastern Madagascar. Cooler than normal conditions are forecast for northern Algeria, northern Tunisia, and western Mozambique,.

In the Middle East, conditions in Iraq east of the Euphrates River will also be cooler than normal, and across the border into western Iran. Anomalies are expected to be extreme east of Baghdad. In Central Asia, Kazakhstan will be moderately warmer than normal; moderate to extreme warm anomalies are forecast for eastern Tajikistan.

Intense warm anomalies are expected in southwestern Pakistan and in much of India except the Gangetic Plain. Exceptional anomalies are forecast for eastern Maharashtra, central Chhattisgarh, Odisha, and Sri Lanka. Conditions will be cooler than normal in eastern Nepal into Bhutan, India, and northern Bangladesh.

In East Asia, moderate warm anomalies are expected in Mongolia, Northeast China, around Beijing, and much of the Korean Peninsula. More intense anomalies are forecast in Tibet north of the Yarlung (Brahmaputra) River, western Sichuan, and southern and southeastern China. Anomalies will be exceptional in Hong Kong, Hainan, and Taiwan.

Thailand, Laos, and central Vietnam will be exceptionally warmer than normal, and intense warm anomalies are forecast for remaining regions in Southeast Asia as well as Malaysia, Indonesia, and Philippines. Anomalies may be exceptional in Singapore, Luzon (Philippines), Sulawesi and Papua, Indonesia.

Exceptional warm anomalies are forecast in eastern Queensland, Australia from Rockhampton in the north past Brisbane in the south, downgrading to moderate or severe as they trail south past Sydney. Primarily moderate anomalies are forecast for Western Australia with severe anomalies south of the Hamersley Range. Severe warm anomalies are also forecast surrounding Katherine in the northern region of Northern Territory.

Many regions of South America will be warmer than the norm. Warm anomalies of varying intensity are forecast for nations across the north; many Brazilian states but particularly western states; a vast path in the western part of the continent following the Andes mountains; and in the Pampas. Anomalies are expected to be exceptional in eastern Bolívar (Venezuela), Suriname, French Guiana, Amapá and Rondônia (Brazil) into northern Bolivia, and along the Andes from Peru to Santiago, Chile. Anomalies will be intense in the western Amazon Basin and from Bogota (Colombia) to Cuenca (Ecuador).

In Central America and the Caribbean, exceptional warm anomalies are forecast for Costa Rica and anomalies nearly as intense in Panama. Guatemala and neighboring areas will be moderately warmer than normal. Moderate to severe warm anomalies are expected in Nayarit, Mexico, and in western Sonora, Chihuahua, Coahuila, and Durango, but anomalies will be severe throughout the Baja Peninsula.

In North America, Alaska jumps out on the map with a forecast of exceptionally warmer than normal temperatures across its vast southern half and well into Yukon and British Columbia, Canada. In the conterminous U.S., moderate to severe warm anomalies are forecast in the eastern half of the nation, in the Southwest, the Rockies, and the Pacific Northwest. In Canada, similar conditions are forecast from Manitoba through central Quebec; moderate warm anomalies in Alberta; and severe to exceptionally warmer conditions in British Columbia.

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 April 2, 2019 which includes forecasts for April 2019 through December 2019 based on NOAA CFSv2 forecasts issued March 25 through March 31, 2018.

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.

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