Global Precipitation & Temperature Outlook October 2021

Global Precipitation & Temperature Outlook October 2021

5 October 2021

OVERVIEW
While the October 2021 forecast indicates hotter than normal temperatures in many regions, Nigeria stands out with both exceptionally hotter and exceptionally drier conditions. Notable also is Quebec, Canada, where most of the province’s vast expanse will be exceptionally hotter. Beijing, China and the surrounding region will be much wetter than normal.

PRECIPITATION OUTLOOK
In Africa, precipitation deficits are expected throughout much of Nigeria outside of the Niger Delta and will include exceptional deficits spanning the river’s lower reaches through Enugu State, in the northeast, and through northern Cameroon into Central African Republic. A pocket in eastern C.A.R. will also see intense precipitation deficits. Moderate to severe deficits are forecast for southern Chad, northern Benin, Burkina Faso, and Niger’s southwest corner. Pockets of moderate deficit are expected in North Africa, particularly Algeria, and in West Africa and southwestern Sudan.

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.

Around the southern Gulf of Guinea, conditions will be wetter than normal along Cameroon’s southwestern border into Equatorial Guinea, and from south-central Gabon into westernmost Republic of the Congo. Further south along the Atlantic Coast, moderate deficits are forecast for southwestern Angola and much of central Namibia.

In the Horn and East Africa, conditions are forecast to be wetter than normal in Djibouti, pockets of the Ethiopian Highlands, Somalia’s northern reaches, southeastern South Sudan, and from Uganda into Kenya and northern Tanzania’s Serengeti Plains. A few pockets in Democratic Republic of the Congo will be moderately wetter than normal, including an area west of Lake Tanganyika. Precipitation deficits are forecast from southeastern Ethiopia into Somalia and northeastern Kenya, and in Kenya’s southern tip. Deficits will be severe in Ethiopia between the Shebele and Genale (Jubba) Rivers. Somewhat drier than normal conditions are expected in pockets of eastern Zambia, northeastern Mozambique, and Madagascar’s northern and southern extremes.

South Africa will be moderately wetter than normal from Johannesburg to the coast.

Europe can expect wetter than normal conditions in northern Sweden’s Västerbotten County; southern Norway west of Oslo; Denmark’s northern tip; the United Kingdom; Brussels; the Champagne region in northeastern France, and the Lower Loire River region and Brittany on the Bay of Biscay; around Lake Geneva (Lac Léman) in Switzerland; and the Caucasus Mountains in southern European Russia. Surpluses will be moderate overall. Much of the Balkan Peninsula will be moderately drier than normal with conditions reaching well into western Romania. Precipitation deficits will be severe near the Iron Gates Dam on the Danube in Romania and throughout much of Bulgaria. Moderate deficits are forecast in southeastern Spain, particularly in eastern Andalusia, and mild deficits in Poland, Belarus, and Ukraine.

Conditions will be moderately drier than normal in pockets of the Middle East including Isfahan Province in central Iran, Ha'il Region in north-central Saudi Arabia, southern Syria and around Aleppo in the north, Cyprus, and pockets of Jordan and northern Iraq. In Turkey, deficits will be widespread in the western half of the nation, extreme east of Istanbul along the Black Sea Coast and severe in the Taurus Mountains of the south, along the Aegean Coast, and west of Istanbul. Generally moderate precipitation surpluses are predicted for southwestern Yemen.

Relatively normal precipitation is forecast for most of Central Asia and Russia. However, deficits are expected in eastern Tajikistan, west of Lake Baikal between the Lena and Angara Rivers in Russia, and surrounding Batagay on the Yana River in northern Sakha Republic. Deficits will be moderate overall. Moderately wetter than normal conditions are forecast in the Russian Arctic on the Kara Sea near the Yamal Peninsula, and a pocket in the Koryak Mountains in the Far East.

In South Asia, many regions of India can expect above normal precipitation though no exceptional anomalies are forecast. In the west, severe surpluses are expected from Gujarat well into Madhya Pradesh and Maharashtra, moderating as they expand outward, but surpluses will be extreme in the Tapi River Watershed of northwestern Maharashtra. Severe surpluses are forecast in eastern Rajasthan reaching through northern Madhya Pradesh into Uttar Pradesh. Farther east, moderate surpluses are expected in Chhattisgarh and southern Bihar, swinging north into eastern Nepal and through northern Bangladesh into neighboring Indian States. In southern India, moderate to severe surpluses are forecast, and moderate surpluses are forecast in southern Sri Lanka. In northern India, moderate to severe deficits are expected in Jammu and Kashmir and a few moderate pockets in northern Uttar Pradesh. Northern Pakistan will be moderately drier than normal as will Afghanistan’s northern half. Conditions are also expected to be moderately drier around Herat in western Afghanistan. Central Punjab in Pakistan will be moderately wetter than normal.

In East Asia, a vast belt of surplus precipitation is forecast in China from southern Xinjiang through the Yellow River (Huang He) Watershed and north past Beijing. Beijing and the surrounding region will be exceptionally wetter than normal as will the Qaidam Basin in northern Qinghai and the central Kunlun Mountains region in Xinjiang. Elsewhere in Xinjiang, surpluses are forecast in the north, exceptional in the Tian Shan Range, severe south of Urumqi, and moderate in the far north. Areas in China with a forecast of moderate deficit include western Tibet (Xizang), western Sichuan, Guizhou, and Guangxi. Northern Taiwan will be moderately wetter that normal, moderate to severe surpluses are forecast for northern North Korea, and relatively normal precipitation is expected in Japan.

Myanmar can expect moderate precipitation deficits in the Irrawaddy Delta and moderate surpluses in the nation’s northwest in the middle region of the Chindwin River. Elsewhere in Southeast Asia, a pocket of moderate deficit is expected in northern Laos where the Ou joins the Mekong, and moderate surpluses are forecast in pockets of the western Philippines, Java, the Maluku Islands, and southern New Guinea.

Australia can expect moderate surpluses in Western Australia from the Gascoyne into the Murchison area. Precipitation in New Zealand and New Caledonia will be relatively normal.

In the Western Hemisphere, moderate surpluses are predicted for the Amazon River’s northern and eastern regions. Surpluses will be extreme in northern Maranhão and severe northeast of Manaus. Elsewhere in South America, surpluses are forecast for southern Guyana, Suriname, and northern French Guiana; from Loreto Department in Peru reaching north along a wide path through Columbia to Venezuela; and in pockets of western Columbia. Surpluses will be moderate overall but extreme in northeastern Columbia and severe in northwestern Loreto. Drier than normal conditions are forecast from Cochabamba, Bolivia along a path leading south into Argentina. Pockets of deficit are also expected near Caracas, Venezuela; Valparaiso and Santiago, Chile; a pocket in the northern Pampas of Argentina and near the southern border with Chile. Small, isolated pockets of deficit are expected throughout the Peruvian Andes.

Northern Central America can expect moderate deficits. Some moderate surpluses are forecast in Costa Rica. No significant precipitation anomalies are forecast in the Caribbean.

Deficits in northern Central America will reach into Mexico’s Yucatan Peninsula and southern states between the Gulf of Mexico and Gulf of Tehuantepec. Moderate surpluses are forecast in a pocket north of Mexico City and moderate surpluses will be widespread in the north from eastern Chihuahua well into Coahuila and south through eastern Durango into Zacatecas.

Moderate precipitation surpluses are also forecast in the United States in southern Texas, eastern new Mexico into Texas, central Nebraska into Kansas, south of Fargo in North Dakota, and north of Seattle, Washington. Deficits are expected in southern Florida and a few pockets in the state’s north.

Widespread, moderate to severe precipitation deficits are forecast in central Quebec, Canada, moderating as they reach east into Labrador and south. Moderate to severe deficits are also expected in Nova Scotia. In Ontario, moderate deficits are forecast east of Georgian Bay and in the province’s far northwest. In western Canada, British Columbia will be moderately wetter than normal in the south from the Thompson River to the U.S. border, and in the north near Williston Lake. Widespread surpluses are forecast in Nunavut.

TEMPERATURE OUTLOOK
Outside of Canada’s far western regions, the vast expanse of the nation will experience warmer than normal temperatures. Exceptionally hotter than normal conditions will blanket much of Quebec, Labrador, and the Maritimes, and extremely warmer than normal temperatures will dominate Newfoundland. In the major metropolitan areas of the east, Quebec City will be extremely hotter than normal, Montreal severely hotter, and Ottawa and Toronto moderately hotter. Temperatures throughout Southern Ontario are expected to be moderately to severely above average while Northern Ontario can expect severe to extreme warm anomalies. In the Prairie Provinces, southern regions of Saskatchewan and Manitoba will be moderately warmer than normal overall, but warm anomalies will be more intense in the north. Northeastern Alberta will be moderately warmer than the norm, but Northwest Territories and Nunavut will be much hotter than normal, with exceptional anomalies in a vast area of Nunavut around Hudson Bay.

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.

Temperatures in the eastern half of the United States will be moderately warmer than normal overall but large areas will see deviations from the norm of greater intensity. Extreme to exceptional anomalies are forecast for Maine, downgrading to severe in neighboring states. Severe warm anomalies are also expected from Central Appalachia into the Blue Ridge Mountains. In the Great Lakes Region, Michigan can expect to be extremely warmer than normal in the north. Severe warm anomalies are forecast in southern Michigan, Wisconsin, and northern Minnesota. Moderate warm anomalies are expected in the Mississippi River Basin and moderate to severe anomalies in the Missouri Basin. A pocket near Cheyenne, Wyoming will be extremely hotter than normal. Much of Idaho will be moderately warmer than normal as will northeastern Utah, pockets of Nevada, southwestern Arizona, and parts of the Panhandle and Big Bend Country in Texas.

Northwestern Mexico will be somewhat cooler than normal spanning the border of Sonora and Chihuahua and from Sonora’s southern tip into Sinaloa. Baja California will be moderately warmer than the norm. Moderate warm anomalies are also forecast in the north-central region of the nation but will be severe in Coahuila. Along the Pacific Coast, intensely hotter than normal temperatures are expected in Nayarit and Jalisco, and farther south from Oaxaca through Chiapas. Moderate warm anomalies are forecast for southern states along the Gulf of Mexico and into the Yucatan Peninsula, but anomalies will be severe in eastern Campeche.

Warm anomalies of varying intensity are forecast throughout Central America and the Caribbean including exceptional anomalies in Jamaica.

In South America, eastern and southeastern Brazil will be warmer than normal with extreme to exceptional anomalies in the smaller eastern states and moderate to extreme anomalies from Amapá in the north into Paraná in the south. Western Amazonas will be moderately warmer than normal while its northeastern region will be cooler. Warm anomalies of varying intensity are forecast throughout the Andes from western Venezuela reaching as far south as Copiapo, Chile where anomalies will be intense. Areas with a forecast of exceptional anomalies include the region south of Huancayo, Peru, and southwestern Bolivia including La Paz.

Moderate warm anomalies are predicted from southern Colombia into northern Peru, and severe anomalies in south-central Venezuela. A pocket in the northern Orinoco Watershed in Venezuela will be somewhat cooler than normal.

Much of Europe and northern European Russia will be warmer than normal, moderately warmer overall but anomalies will be exceptional in Corsica and extreme in Sardinia and southeastern Spain. Several regions are expected to experience severe anomalies, including southern Italy; central, southern, and northeastern Spain; Provence; Switzerland, western Austria and southern Germany; and southern Norway. Relatively normal temperatures are forecast for the eastern Balkans, eastern Ukraine, and the United Kingdom.

Warm anomalies of varying intensity are expected in Africa from Tunisia through northern Algeria and Morocco, and curving in a vast arc encompassing West Africa and nations along the Gulf of Guinea. Anomalies will be exceptional in northwestern Algeria and many regions from coastal Guinea through three-quarters of Nigeria. From there, extreme to exceptional anomalies are forecast in Cameroon, Central African Republic, and Equatorial Guinea. Anomalies of generally lesser intensity are expected in northern and western Democratic Republic of the Congo (DRC), Republic of the Congo, and Gabon. Much of Angola and Zambia can expect warmer than normal temperatures, moderating as they reach through Zimbabwe and Botswana.

Around the Horn of Africa and East Africa, temperatures will be much warmer than normal in many regions but especially widespread and exceptional in eastern Sudan, western Somaliland, eastern Ethiopia, southern Somalia, and southern Kenya. Intense warm anomalies are also expected in Tanzania but anomalies will be generally moderate in parts of Mozambique. Madagascar will be warmer than normal as well.

Cooler than normal conditions are expected in the eastern Sahara Desert, South Sudan, a pocket in southeastern DRC on the Lukuga River, and west-central Namibia. Anomalies will be exceptional in the Sudd in South Sudan.

In the Middle East, much of the Arabian Peninsula will be exceptionally hotter than normal and similar anomalies will reach through southern Iraq and well into Iranian provinces on the Persian Gulf. Temperatures will be cooler than normal in southern Jordan, along the Black Sea Coast in Turkey and Georgia, and spanning the border of Armenia and Azerbaijan.

Much of Central Asia will see normal temperatures but conditions will be cooler than the norm in eastern Kyrgyzstan and moderately to severely warmer than the norm in eastern Tajikistan. In Russia, most of Siberia will be moderately warmer than normal. Novaya Zemlya in the Kara Sea is expected to be moderately to extremely warmer than normal.

Many regions of South Asia can expect temperatures above normal. In India, widespread warm anomalies are forecast in the south; from Madhya Pradesh in central India to the Bay of Bengal; in the west in coastal Gujarat and through western Rajasthan; in the far north; and Far Northeast. Anomalies will be extreme to exceptional at the intersection of Karnataka, Andhra Pradesh, and Tamil Nadu; Chhattisgarh and pockets of Odisha; the Far Northeast; Gujarat’s coastal tips; and Himachal Pradesh and Jammu and Kashmir. In the Gangetic Plain, temperatures will be moderately warmer than normal around Lucknow in Uttar Pradesh but cooler than normal in a pocket of the state’s northeast.

Bangladesh will be much hotter than normal with extreme to exceptional anomalies. Warm anomalies of varying intensity are expected in western and northern Nepal and eastern Bhutan with severe anomalies in Kathmandu. Pakistan, too, will see warm anomalies of varying intensity, exceptional near the coast including Karachi. Afghanistan will be moderately warmer than normal north of Kabul but anomalies will be severe to exceptional from Kabul nearly to Kandahar.

Intense warm anomalies are forecast throughout most of Southeast Asia. Exceptional anomalies will dominate Myanmar’s southern half and northwestern Thailand. Anomalies of varying intensity are forecast for Malaysia, Indonesia, the Philippines, and New Guinea. Anomalies will be exceptional in many areas including Malaysia, Sumatra, and the Philippines.

In East Asia, severe to extreme warm anomalies are forecast for Japan in Honshu and the southern islands. Extreme warm anomalies are forecast for much of South Korea while North Korea will be moderately warmer than the norm. In China, widespread warm anomalies of varying intensity are forecast along the East China Sea, in Southeast China, South China, Tibet (Xizang), southern Xinjiang, Qinghai, and western Inner Mongolia. Anomalies will be extreme near Shanghai, in northern Qinghai, and in southwestern Sichuan, and will reach exceptional intensity in southern Tibet. Taiwan, too, will be exceptionally hotter than normal.

Northern Australia will be warmer than normal with exceptional anomalies in Top End, Northern Territory and the Cape York Peninsula in Queensland. Warmer than normal conditions anomalies will reach south through Queensland to Brisbane where anomalies will be severe. Tasmania will be warmer than normal, particularly in the south including Hobart. North Island, New Zealand can expert moderate warm anomalies but anomalies in South Island will be severe overall and extreme in Canterbury. New Caledonia will be extremely hotter than normal.

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, 2021 which includes forecasts for October 2021 through July 2022 based on NOAA CFSv2 forecasts issued September 24 through September 30, 2021.

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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