Global Precipitation & Temperature Outlook August 2021

3 August 2021

OVERVIEW
The ISciences Precipitation and Temperature Outlook for August 2021 indicates a forecast of much hotter than normal temperatures for a number of regions notably Japan, site of the Summer Olympic Games currently in progress. Much of Brazil, too, will be exceptionally hot, and the northern Amazon Basin is expected to be much wetter than normal.

PRECIPITATION OUTLOOK
In South America, exceptional precipitation surpluses are forecast in Amazonas, Brazil, in the region surrounding the confluence of the Amazon River and the Rio Negro, moderating as they reach outward. Moderate surpluses are forecast in the Upper Tocantins River Watershed in Pará State around the Tucuruí Reservoir. Surpluses of varying intensity are expected in Brazil’s small northeastern states. Wetter than normal conditions will be widespread south of the Orinoco River in Venezuela and in the northeast reaching into northern Guyana. A pocket of moderate surplus is forecast in Central French Guiana. Surpluses, primarily moderate, are expected in southwestern Bolivia.

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.

Central Bolivia will see moderate deficits; mild to moderate pockets are forecast in many regions of Peru; and small pockets in Ecuador, northern Colombia, and near Caracas, Venezuela. Much of Paraguay will be moderately drier than normal. Similar conditions are forecast in pockets of southern Brazil, Uruguay, and northern Argentina though precipitation deficits will become severe in the Argentine Andes region reaching across the border into Chile. Moderate deficits will pock Argentina’s Atlantic Coast in Buenos Aires Province and Patagonia, but moderate surpluses are expected in southernmost Patagonia.

In Central America and the Caribbean, eastern Honduras and Haiti will be drier than normal while moderate surpluses are forecast in pockets of Panama, Belize, and eastern Guatemala. Mexico’s Yucatan Peninsula will also see moderate surpluses. In the nation’s northwest, however, surpluses of greater intensity are forecast from Sonora into Chihuahua. Near the central Pacific Coast, western Durango and western Jalisco will be somewhat wetter than normal. Pockets of moderate to severe deficit are forecast in central and northeastern states and along the southern shore of the Gulf of Mexico.

Several regions of the United States are expected to be somewhat wetter than normal. Mild to moderate surpluses are forecast from eastern Texas through the Gulf States and Florida, and north through the Carolinas, Virginia, and into Maryland. In the West, similar conditions are forecast from southern Idaho through Utah, much of Arizona, parts of New Mexico, and into western border areas of Texas. Nevada and Oregon will also see some pockets of surplus. Precipitation in Canada will be relatively normal.

The Czech Republic in Central Europe will be moderately wetter than normal as will southern Moldova. Moderate deficits are expected in central and southern Italy, becoming severe along the nation’s west coast through Rome and near Naples. In the Balkans, deficits will be moderate in Kosovo, Macedonia, Albania, and northern Greece. Norway’s northern extreme will also see moderate deficits.

Precipitation anomalies in Africa will be mild, overall. However, some severe deficits are expected in Somaliland and eastern Ethiopia, and moderate pockets elsewhere including eastern Zimbabwe and northwestern Angola. Areas with a forecast of wetter than normal conditions include southern Tanzania, Kenya’s northwestern corner, western Uganda near Lake Albert, and Djibouti.

Moderate to severe deficits are expected in much of Turkey, and deficits in western Georgia will reach extreme intensity. Elsewhere in the Middle East, surpluses of varying intensity are forecast for northern and northwestern Iran, reaching into Turkey and Kirkuk, Iraq. Some pockets of moderate surplus are expected in Iran’s central south. On the Arabian Peninsula, moderate to severe deficits are forecast in eastern Oman, southwestern Saudi Arabia, and some pockets in Yemen.

In Central Asia, western Tajikistan will be much wetter than normal, including Dushanbe, as will southeastern Kyrgyzstan. In Russia, moderate precipitation deficits are expected in the Upper and Middle Yenisei River Watershed, and some moderate surpluses in pockets of Russia’s Far East north of the Sea of Okhotsk.

South Asia can expect moderate surpluses in Bangladesh and southern India, becoming severe as they reach Sri Lanka. Gujarat in western India will be moderately drier than normal but dry anomalies will be more intense in India’s Far North, and will reach extreme intensity spanning the border of Uttar Pradesh and Bihar in the Gangetic Plain. Deficits are also forecast for parts of Nepal and central Pakistan.

In East Asia, widespread, primarily moderate surpluses are expected in Southeast China but anomalies will be extreme to exceptional in southern Taiwan. Surpluses are also expected in Guangdong’s Leizhou Peninsula which dangles in the South China Sea. In western China, conditions will be wetter than normal in the Kunlun Mountains of Tibet (Xizang), the Quilian Mountains of Qinghai, and the Aksu River region of Xinjiang near Kyrgyzstan. Some pockets of moderate deficit will dapple northwestern China. Central and northern Mongolia will be wetter than normal.

The forecast for Southeast Asia includes deficits in central and southern Vietnam, eastern and coastal Cambodia, Thailand’s southeast corner, and the Lower Irrawaddy River region and delta in Myanmar. Deficits will be extreme in central Vietnam and the Mekong River region in Cambodia. In the Pacific, the central and northern Philippines will be moderately drier than normal, but Indonesia and nearby regions can expect somewhat more precipitation than usual, with severe to extreme surpluses in the Lesser Sunda Islands.

Precipitation in Australia and New Zealand will be relatively normal. Some pockets of moderate surplus are forecast in northeastern Queensland and along the coast of Northern Territory near Darwin. New Zealand will be moderately wetter than usual south of the Waitaki River and moderately drier on North Island in Gisborne District in the east.

TEMPERATURE OUTLOOK
Temperatures in Japan, site of the Summer Olympic Games currently in progress, will be exceptionally hotter than normal. Elsewhere in East Asia, the Korean Peninsula can expect warm anomalies ranging from severe to exceptional. Temperatures in Northeast China and the North China Plain will be relatively normal but warm anomalies are predicted for many other regions of the nation. Beijing can expect severe heat anomalies, moderating as they reach into surrounding areas. Shanghai will be moderately warmer than normal as will Taiwan, while anomalies of varying intensity are forecast in Southeast and South China, including exceptionally hotter temperatures in Hainan. Other regions with a forecast of much warmer than normal conditions include Yunnan, Tibet (Xizang), Xinjiang in the northwest, western Inner Mongolia, and the upper Han River region, a tributary of the Yangtze. In Mongolia, temperatures are expected to be normal in Ulaanbaatar but moderately warmer in the nation’s northwest and in the central south (western Gobi Desert).

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.

Nearly all regions in Southeast Asia and the Pacific will be warmer than normal. Severe to extreme anomalies are forecast throughout Southeast Asia and exceptionally hotter temperatures in Cambodia and pockets of Vietnam. Much of the Philippines will experience exceptional heat, as will the Lesser Sunda Islands. New Guinea is forecast to be exceptionally hot. Heat anomalies of varying intensity are forecast for remaining areas in the region.

While temperatures in Australia’s southwest quadrant will be normal, warmer conditions are expected elsewhere. Severe to exceptional anomalies will dominate Queensland including intense heat from Rockhampton past Brisbane. New South Wales will be moderately warmer overall but temperatures will be more intense in the east, reaching extreme intensity on the coast including Sydney. Moderate to severe anomalies are forecast for Victoria and Tasmania. Severe warm anomalies are expected in the nation’s north from the Kimberley Plateau through much of Northern Territory but temperatures will be more intense in Darwin, Arnhem Land, and around the Gulf of Carpentaria. All of New Zealand is forecast to be warmer than normal, exceptionally warmer along South Island’s east coast through Christchurch.

In South Asia, India can expect warmer than normal temperatures in a vast area from Bhopal to the nation’s southern tip, and also in the northern extremes and Far Northeast. Anomalies will be extreme to exceptional in states along the northern Bay of Bengal and from Karnataka through Kerala in the south. Sri Lanka will be warmer than normal. Warm anomalies of varying intensity are forecast for Bangladesh, Nepal, and Bhutan. Pakistan’s westernmost province, Balochistan, will be exceptionally hotter. Conditions in Afghanistan will be warmer along a broad north-south path from Mazar-e Sharif to the Pakistan border, and also south of Kandahar.

Central Asia will be warmer than normal with moderate to severe anomalies and some pockets of exceptional heat. Kyrgyzstan, however, can expect to be moderately cooler than normal in the east. A vast area of Russia is forecast to be warmer from the Ural Mountains through the Central Siberian Plateau. Anomalies will be extreme to exceptional from the eastern Ob River Watershed through the lower and middle regions of the Yenisei River Watershed. Magadan Oblast in Russia’s Far East will be cooler than normal.

In the Middle East, exceptional heat anomalies are forecast for the Levant and areas in Iraq west of the Euphrates River. Warm anomalies of varying intensity are expected on the Arabian Peninsula including exceptional heat in Riyadh, Saudi Arabia and northern Oman; extreme anomalies in Bahrain, Qatar, and UAE; and severe anomalies in Yemen. Al Wusta Governate in Oman will be somewhat cooler than normal. Conditions in Turkey will be exceptionally hotter on its southern coast and in the west, generally moderate elsewhere. The Black Sea coastline will be cooler than normal. In Iran, warm anomalies are expected along the Caspian Sea and through the northeast, near the Persian Gulf, and in Yazd Province. Anomalies will be intense in Yazd and on the Persian Gulf.

Temperatures will be relatively normal in much of Europe. However, Iceland, much of Greenland, and the Balkans will be warmer than normal with some areas of Greenland exceptionally hotter. Severe to extreme anomalies are forecast in Iceland, Macedonia, Albania, and Greece, and widespread moderate anomalies in Romania and Bulgaria. Southern Italy will be moderately warmer as well but anomalies may be more intense in Sicily. Temperatures west of Bologna will be moderately cooler than normal as will a pocket in northern Spain in the central Cantabrian Mountains. Southeastern Spain will be moderately warmer. In Northern Europe, moderately warmer temperatures are forecast in southern Norway.

Widespread warm anomalies of varying intensity are expected across northern Africa with exceptionally hotter temperatures dominating much of Egypt and northern Sudan. Exceptionally hotter conditions are also expected from Guinea in West Africa through nations around the Gulf of Guinea, downgrading as they reach inland. In the Horn of Africa, severe warm anomalies are expected in the Ethiopian Highlands and southern Kenya, and moderate warm anomalies in southern Somalia. Central South Sudan will be cooler than normal as will the southern Congo Basin. In southern Africa, moderate to severe warm anomalies are forecast for many areas along with more intense conditions in north-central Namibia and in South Africa’s northeastern provinces.

In South America, a vast area in central Brazil as well as its far northeastern states will be exceptionally hotter than normal with temperatures of lesser intensity in the surrounding areas. Across the northern arc of the continent, temperatures are expected to be moderately warmer overall from Ecuador through Colombia and into western Venezuela. A few cool pockets are forecast in Venezuela’s central north. The Guianas will be warmer than normal with some severe anomalies in northern Guyana reaching into the Upper Caroni River region of Venezuela. Warm anomalies are expected through the Peruvian Andes and will include some areas of exceptionally hotter temperatures. Bolivia’s southern corner, much of Chile, and most of Argentina will be warmer than normal with moderate to severe anomalies overall.

Warm anomalies of varying intensity are forecast throughout Central America. In the Caribbean, warmer than normal temperatures are predicted for the Bahamas, Jamaica, and in Cuba’s western tip, with exceptional anomalies near Havana. Mexico can expect intensely warmer conditions in Baja, the north-central states, from Mazatlán to Acapulco on the west coast, and in the south between the Gulf of Mexico and the Gulf of Tehuantepec. The Yucatan will be moderately warmer than normal as will northern Veracruz. Cooler than normal temperatures are forecast in northwestern Mexico spanning the border of Sonora and Chihuahua.

In the United States, warmer temperatures are forecast in the West, Pacific Northwest, and Montana, moderate overall but severe at the intersection of Oregon, Idaho, and Washington, and in Reno, Las Vegas, and western Arizona. Temperature anomalies could be extreme in Death Valley, California. Elsewhere, moderate to severe warm anomalies are forecast for northern Michigan, much of New England, Florida, and a pocket of southwestern Mississippi. Texas will be much warmer south of Corpus Christi, and moderately warmer in Terrell County, West Texas. Central Oklahoma will be cooler than normal as will a pocket in northwestern Colorado.

Alberta and British Columbia, Canada, will be moderately warmer than normal with conditions reaching into the Yukon and Northwest Territories. Anomalies will be more intense near BC’s north-central border and in the Fraser Plateau in the center of the province. Likewise, anomalies will be severe around Lesser Slave Lake in Alberta and in Alberta’s southwest corner. Northeastern Manitoba into Ontario will be moderately warmer but the southern region of Lake Winnipeg could see extremely warmer temperatures. Moderate to severe warm anomalies are forecast in Ontario around Lake Superior. Eastern Canada can expect mild to moderate warm anomalies with severe anomalies in eastern Labrador and Nova Scotia.

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 August 2, 2021 which includes forecasts for August 2021 through April 2022 based on NOAA CFSv2 forecasts issued July 25 through July 31, 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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