Global Precipitation & Temperature Outlook November 2020

3 November 2020

OVERVIEW
The Outlook for November 2020 indicates that the Orinoco River Watershed of Venezuela will be much wetter than normal, while the Andes region through western Colombia and Ecuador will be much drier. Much of Madagascar will be drier than normal as well. The western U.S. can expect to be hotter than normal, particularly the Southwest. And nearly all of the vast expanse of Russia will see temperatures above normal.

PRECIPITATION OUTLOOK
In South America, precipitation surpluses are forecast from Venezuela reaching into eastern Colombia, Guyana, Suriname, French Guiana, and the eastern Amazon Basin in Brazil. Surpluses will be exceptional south of the Orinoco in the Guiana Highlands of Venezuela. In western Colombia and Ecuador through the Andes Range conditions will be drier than normal with moderate to exceptional precipitation deficits. Deficits are also forecast for central and southern Chile and will reach extreme intensity in pockets of the Lake District in the south and across the border into Patagonian Argentina. Generally moderate precipitation deficits are expected in north-central Argentina; Uruguay; Rio Grande do Sul, Brazil; and following the Cordillera Oriental Mountains through southeastern Peru, western Bolivia, and northwestern Argentina. Some pockets of moderate surplus are forecast in Mendoza Province, Argentina and in northern Paraguay.

A few small pockets of precipitation surplus are expected in Central America and the Caribbean. Conditions in Mexico will be relatively normal.

Near-normal conditions are also forecast for many areas of the U.S. but moderate to severe deficits are expected in Wyoming and Colorado; and moderate deficits in Southern California, a few pockets in Texas west of Amarillo and east of San Antonio, and in Michigan’s Upper Peninsula. Northern Alaska will be wetter than normal as will the state’s Panhandle region.

Canada’s northern Yukon will be moderately drier than normal but wetter than normal conditions are forecast in a broad path from northern British Columbia into northwestern Alberta, western Northwest Territories, and also from northern Saskatchewan and Manitoba into southern Nunavut reaching Hudson Bay.

Precipitation in Europe will be normal with some surplus in northern Scandinavia.

In Africa, Madagascar stands out with a forecast of moderate to extreme precipitation deficits throughout much of the country. Across the Mozambique Channel in mainland Africa, moderate deficits are forecast in central Mozambique and in Zimbabwe. Elsewhere, drier than normal conditions are forecast for Sierra Leone and Guinea reaching into southern Mali, and pockets of Burkina Faso, Ghana, Togo, Benin, and Nigeria. Deficits will be severe in Benue State, Nigeria. Deficits will also be severe in a strip of eastern South Sudan between the Kangen River and the Ethiopian border. Surpluses are expected in many other regions of South Sudan, particularly the north, and will be extreme to exceptional on the White Nile. Areas with a forecast of generally less intense surplus include Ethiopia’s western border region, northeastern Uganda, central Tanzania, western South Africa, southern Republic of the Congo, and south-central Côte d’Ivoire.

Moderately drier than normal conditions are forecast in Saudi Arabia, southern Iraq, and the bulk of central Iran. Deficits may be extreme in Ha’il Province in northern Saudi Arabia.

Moderate precipitation deficits are also forecast in Afghanistan, northern Pakistan, Far North India, and pockets of Tajikistan, Turkmenistan, and Uzbekistan. Deficits will reach severe intensity in Gilgit-Baltistan, Pakistan (formerly Northern Areas). Some moderate deficits are expected in scattered pockets of India’s western coast. Bangladesh can expect surpluses with severe to extreme conditions in Dhaka District. Surpluses will reach east through the Indian states of Nagaland and Manipur but will be moderate.

In Southeast Asia, northern Myanmar will be moderately wetter than normal as will southern Laos into central Vietnam. Deficits are forecast in northwestern Vietnam and Peninsular Thailand. Some pockets of surplus, primarily moderate, are expected in Indonesia. Surpluses will be widespread in southern Papua, Indonesia and into Papua New Guinea.

The southern portion of Western Australia is forecast to be wetter than normal and similar conditions are expected in central Northern Territory, southeastern Queensland, and pockets in the eastern Murray-Darling Basin.

China can expect moderately drier than normal conditions in the north from the Bohai Sea to the Mongolia border, and precipitation deficits ranging from moderate to severe will cover much of southern Mongolia. Pockets of moderate deficit are forecast in other regions of China including northern Gansu into Qinghai, central Sichuan, and along the southeast coast. Moderately wetter than normal conditions are forecast for southern Qinghai, Chongqing, and far northern Inner Mongolia. Southern Japan will be drier than normal with severe deficits near Tokyo.

Russia will be wetter than normal from the Urals through the Western Siberian Plain and south past Lake Baikal. Surpluses will be generally moderate but may be slightly more intense near Baikal. Surpluses are also expected along the Laptev and East Siberian Seas and the Sea of Okhotsk.

TEMPERATURE OUTLOOK
Nearly all of Russia is expected to be warmer than normal with extreme to exceptional anomalies - conditions that occur once in 20 to 40 years - in the Arctic along the East Siberian Sea reaching well inland. In western Russia, Moscow will be moderately warmer than normal, St. Petersburg will be extremely warmer, and exceptional anomalies are forecast south of Volgograd.

In Central Asia, much of Kazakhstan will be moderately warmer than normal but conditions will be more intense north of the capital, Nur-Sultan (Astana), and in the northern Caspian Basin. Western Uzbekistan, western Turkmenistan, and eastern Tajikistan will be moderately warmer than normal.

Temperatures in South Asia will be near-normal in much of Afghanistan, Pakistan, and the bulk of central India. However, India’s southern tip and Sri Lanka will be exceptionally warmer. The country’s Far Northeast can expect severe to exceptional warm anomalies, and the Far North will be moderately to severely warmer than normal. Somewhat cooler than normal temperatures are forecast for pockets of Gujarat and Rajasthan. Central Nepal will be warmer than normal, while the east will be cooler. Bangladesh will be moderately warmer with anomalies growing more intense in the east.

China’s forecast indicates normal or moderately warmer conditions in the west, but anomalies of varying intensity in much of the remainder of the country. Yunnan in the south will be extremely to exceptionally warmer than normal as will Qinghai and regions bordering the Bohai Sea. Warm anomalies will be moderate to extreme in the North China Plain; moderate to severe in North China; and moderate in the Southeast including Taiwan. Japan will be moderately warmer than normal but anomalies will reach severe intensity in Hokkaido. Mongolia, too, will be warmer than normal in most regions with intense anomalies in the east.

Much of Southeast Asia, Malaysia, Indonesia, and the Philippines will be warmer than normal. Areas that can expect exceptionally warmer than normal temperatures include southern Myanmar, Phenom Penh (Cambodia), northern Sumatra, the Lesser Sunda Islands, central and southern Philippines, and the Maoke Mountains in the New Guinea Highlands of Papua, Indonesia.

Western Australia will be spared for the most part but warmer than normal temperatures of varying intensity are forecast for the remainder of the nation. Anomalies will be exceptional across the north around the Gulf of Carpentaria from eastern Top End through Far North Queensland, and in nearly all of the southern state of Tasmania. Warm anomalies will be severe to extreme along Australia’s south coast from Adelaide well past Melbourne; moderate in the east near Canberra, Sydney, and Brisbane; and moderate to extreme in the west from Perth leading south. Temperatures in New Zealand will be warmer than normal with severe anomalies overall but extreme anomalies west of Christchurch and north of Auckland. New Caledonia will be much warmer than normal.

Central and Eastern Europe will be moderately warmer than normal as will central Spain and southern Italy. Warm anomalies will be more intense in the Baltic area and far eastern Ukraine.

In the Middle East, warmer than normal temperatures are forecast for Georgia, Armenia, Azerbaijan, eastern Turkey, the Levant, northern Saudi Arabia, Iraq, much of Iran, and Yemen’s southwestern tip. Anomalies will be intense in many pockets. Somewhat cooler than normal temperatures are expected in northern Oman, southern Saudi Arabia, and north of Sanaa in Yemen.

Some moderately warmer than normal temperatures are forecast in northern Africa. Conditions will be more intense in West Africa where coastal nations from the southern reaches of Western Sahara around the Gulf of Guinea can expect anomalies reaching exceptional intensity. Much warmer than normal temperatures are also predicted for nearly all of Madagascar and across the Mozambique Channel in parts of Mozambique, Zimbabwe, Botswana, and northern South Africa. Other regions forecast to be warmer than normal include southern and northwestern Kenya, eastern Tanzania, Rwanda, Burundi, western Democratic Republic of the Congo, Angola, Zambia, and along the Red Sea. Temperatures will be cooler than normal in South Sudan, reaching across its borders into surrounding nations, and in eastern Uganda. Anomalies will be exceptional in eastern South Sudan.

Normal temperatures are forecast for much of South America. However, Brazil’s small far-eastern states can expect to be much warmer than normal with extreme to exceptional anomalies. Warmer than normal temperatures of varying intensity are forecast for northeastern Guyana, southeastern and northwestern Venezuela, Columbia, Ecuador, the Cordillera Central Mountains in Peru, the Cordillera Orientales in Bolivia, pockets of Chile, northwestern Argentina, and Patagonia. Anomalies will be extreme in Guyana and exceptional in pockets of the Andes Range, including near Laz Paz, Bolivia, and in Patagonia. Somewhat cooler than normal conditions are forecast in a pocket of northern Pará, Brazil, and from northwestern Bolivia into Peru.

In Central America and the Caribbean, temperatures will be warmer than normal in southern Guatemala, El Salvador, eastern Nicaragua, Costa Rica, Panama, Jamaica, Haiti, Dominican Republic, and the Bahamas. Anomalies will be intense in Nicaragua and Jamaica.

Many regions of northern Mexico will be warmer than normal with exceptional anomalies in the Baja Peninsula and across the Gulf in northern Sonora. Anomalies will also be exceptional on the central Pacific Coast in Nayarit.

All of the U.S. west of the Mississippi River is expected to be warmer than normal. Anomalies will be exceptional in the Southwest, extreme to exceptional in California and nearby states, severe to extreme in the Rockies, severe with extreme pockets in Nebraska and Kansas, and moderate in remaining areas. Illinois, Indiana, the southern portion of Michigan’s Lower Peninsula, and northern Ohio will also see moderately warmer than normal temperatures. Alaska will be warmer than normal in the north near Barrow.

In Canada, moderately warmer than normal temperatures are forecast for southern British Columbia, but intense warm anomalies are expected in several large islands in Canada’s far north including Victoria, Banks, and Melville Islands in the Beaufort Sea.

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 November 2, 2020 which includes forecasts for November 2020 through July 2021 based on NOAA CFSv2 forecasts issued October 25 through October 31, 2020.

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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