Global Precipitation & Temperature Outlook October 2019

Global Precipitation & Temperature Outlook October 2019

4 October 2019

OVERVIEW
The October Outlook indicates a forecast of much wetter than normal conditions in Africa across the Sahel, and in central Afghanistan. Most of Australia is expected to be warmer than the norm, with exceptional anomalies blanketing nearly all of the nation’s western half.

PRECIPITATION OUTLOOK
Blues and greens on the precipitation map for Africa call attention to the unusual extent of wetter than normal conditions on the continent. Wet anomalies of varying intensity are expected across the breadth of the Sahel and spilling north into the southern Sahara and south into countries along the Gulf of Guinea. Wet anomalies are also forecast in parts of the Horn of Africa and along the east coast through central Mozambique; pockets of the land-locked nations of South Sudan and Uganda; Democratic Republic of the Congo (DRC); and along the central west coast of Africa in Cameroon, Equatorial Guinea, Republic of the Congo, and northern Angola. Anomalies will be extreme to exceptional in southern Sudan, southern Chad, southwestern Nigeria, northern Cameroon, northeastern Tanzania including Zanzibar, coastal Republic of the Congo and coastal DRC, and northwestern Angola.

Some small pockets of moderate dry anomalies are forecast for central Tunisia, northeastern Libya, and western and southern Madagascar.

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.

Most of Europe can expect nearly normal precipitation. Some moderate wet anomalies are forecast for Ireland, Northern Ireland, Scotland, and Belgium. Moderate to severe wet anomalies are expected in northeastern Sweden and across the Gulf of Bothnia into Finland.

Some moderately wetter than normal conditions are forecast in Russia in large pockets of the eastern Vychegda Lowlands, across the northern Urals and the northern reaches of the Western Siberian Plain, and around Mirnyy in southern Sakha Republic. Intense wet anomalies are forecast for the Kamchatka Peninsula in the east and regions to the north of the Peninsula. Some drier than normal conditions are forecast west of Lake Baikal and in the region of Russia between Kazakhstan and Mongolia. Eastern Kyrgyzstan will be somewhat wetter than the norm.

In the Middle East, wet anomalies are forecast for northern Iraq, western and southeastern Iran, and western Yemen. Western Georgia will be moderately drier than normal.

Central Pakistan will be exceptionally wetter, and wet anomalies of varying intensity are forecast for much of the remainder of the country. Moderate wet anomalies are expected in central Afghanistan. India, too will be wetter than normal in many regions, and though anomalies will not be exceptional they are expected to be extreme in Punjab, down the middle of Maharashtra, north of Hyderabad in Telangana, and in southern Odisha. Sri Lanka will also see wet anomalies. Central Bangladesh will be moderately wetter than normal. Dry anomalies are forecast for northwestern Bangladesh, western Bhutan, and pockets of India’s Far Northeast.

Wet anomalies of varying intensity are expected to trace an ever-widening path across China’s breadth from the southern border of Xinjiang in the west past Beijing to the Bohai Sea. Anomalies will be exceptional in southern Xinjiang, western Qinghai, and central Gansu. Southeastern Yunnan will also be wetter than normal. Severe dry anomalies are forecast for southern Tibet. Southeastern South Korea will be moderately wetter than the norm.

Relatively normal conditions are forecast for most of Southeast Asia with some wet anomalies in northern Vietnam, northeastern Laos, and pockets of northern Myanmar, and primarily dry anomalies in central and southern Vietnam. Peninsular Thailand will be much drier than normal, as will northeastern Borneo, southern Sumatra, and central Philippines. Severe dry anomalies are expected in Java. Primarily moderate wet anomalies are forecast for western and southern Borneo, eastern Sulawesi, western and southern Papua, Indonesia and nearby islands.

In Australia, moderate dry anomalies will cover much of the eastern half of the nation and the southwest, but anomalies will be severe to exceptional in Victoria. Primarily moderate dry anomalies are forecast for northern Tasmania. Relatively normal precipitation conditions are expected in New Zealand.

Greenland will be drier than normal and some drier than normal pockets are forecast for Canada in southern Baffin Island, east of Michikamau Lake in Newfoundland and Labrador, and straddling the border of Northwest Territories and Nunavut. Some moderate wet anomalies are forecast for British Columbia. The U.S. can expect similar wet anomalies around Seattle, in North Dakota, eastern Wisconsin, Michigan’s Lower Peninsula, Upstate New York, and northern Vermont. Moderately drier than normal conditions are forecast in Alaska north of Fairbanks and south of Anchorage, and in the southwestern U.S. including southern California, southern Nevada, southern Utah, and northern Arizona.

Northern Mexico will be significantly wetter than normal in a broad path from Chihuahua south through coastal Guadalajara. Wet anomalies are also forecast for Guerrero and parts of the Yucatan, as well as southern Guatemala, El Salvador, pockets of Honduras, western Nicaragua, and Jamaica. Drier than normal conditions are forecast for Panama.

In South America, dry anomalies are forecast through the Andes along the Pacific Coast from Columbia through northwest Ecuador, picking up again in Peru and trailing into southern Bolivia and northwestern Argentina, and will include relatively small intense pockets. Dry anomalies are also forecast for a vast area in central and southeastern Brazil including Mato Grosso, Tocantins, Piauí, Bahia, Goiás, Minas Gerais, Espiritu Santo, and São Paulo. Anomalies will be severe to extreme in São Paulo State.

Wet anomalies of varying intensity are forecast for much of the north and northwest region of the continent, including Guyana, Suriname, Venezuela, most of Colombia, eastern Ecuador, northern and central Peru, and the western Amazon Basin. Similar conditions are forecast for northern Bolivia, Uruguay, and Rio Grande do Sul, Brazil. Anomalies will be exceptional in pockets of Colombia and Peru. Anomalies in Uruguay will be widespread and severe.

TEMPERATURE OUTLOOK
Most of Australia is expected to be warmer than the norm, with exceptional anomalies blanketing nearly all of the nation’s western half from western South Australia up through the center of the Outback, and reaching north to the Kimberley Plateau and west through the Hamersley Range. The area around Katherine in Top End, Northern Territory, will also be exceptionally warmer than normal. In the eastern half of the nation, exceptional warm anomalies are forecast west of Brisbane in the Darling Downs, severe to extreme anomalies in the eastern Murray-Darling Basin, severe anomalies in the western portion of the Basin, and primarily moderate to severe anomalies elsewhere. New Zealand will be somewhat cooler than normal.

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.

Southeast Asia, Malaysia, the Philippines, and many regions of Indonesia will be warmer than normal. Severe to exceptional anomalies are expected in Thailand, Laos, Vietnam, and Cambodia, and some moderate anomalies in Myanmar, though conditions may be more intense from the Gulf of Martaban trailing into southernmost Myanmar. Severe to exceptional warm anomalies are also forecast for Sumatra, Java, northern Borneo and the central and southern Philippines. Cooler than normal conditions are expected in the Bird’s Head (Doberai) Peninsula of West Papua, Indonesia and the nearby island of Seram.

In East Asia, intense warm anomalies are forecast for a vast area of southeastern China with exceptional anomalies blanketing Hainan, Guangxi, Guangdong, southern Hunan, Jangxi, and into Anhui. China’s northeastern provinces will also be warmer than normal, with anomalies reaching extreme intensity. Moderately warmer than normal conditions are expected in much of the center and west of the nation, with more intense anomalies in Qinghai and in the Taklimakan Desert in the west. Exceptionally warmer than normal temperatures will cover the Korean Peninsula. Extreme warm anomalies are expected throughout most of Japan. In Mongolia, severe to extreme warm anomalies are forecast in the east, and moderate to severe anomalies in the west.

Across the border in southern Russia conditions will be much the same as in Mongolia, with severe to extreme warm anomalies surrounding Lake Baikal, and a vast stretch of moderately warmer than normal conditions from east of the Urals to the Sea of Japan. Some moderate warm anomalies are forecast for pockets of southern and eastern Kazakhstan, southern Kyrgyzstan, and central Tajikistan.

In South Asia, intense warm anomalies are expected in southern India, with severe to exceptional anomalies in Karnataka and Kerala. Moderately warmer than normal conditions are forecast in eastern India for states along the Bay of Bengal and into the interior. Pockets of the north will be cooler than normal, including Punjab, eastern Rajasthan, northeastern Uttar Pradesh, and into eastern Nepal and Bhutan’s western tip. Cooler than normal conditions are also forecast for a border-to-border stretch across northern Pakistan from Peshawar in the west past Lahore in the east. Conditions in the southern regions of the country, however, are expected to be warmer than normal and will include exceptional anomalies along the coast through Karachi. Afghanistan’s Ghazni Province in the east-central region can expect warmer than normal temperatures.

Exceptionally warmer than normal conditions are forecast for much of the Arabian Peninsula, around the Persian Gulf into southern Iraq, and well into Iran. West of the Euphrates River in Iraq severe warm anomalies are expected. Northeastern Iran will be moderately warmer than normal, as will eastern Syria. Likewise, moderate warm anomalies are forecast for some pockets of southern Turkey, while Turkey’s northern coast on the Black Sea will be somewhat cooler than normal.

The forecast for Africa includes warm anomalies of varying intensity in the northwest and across the southern Sahara. Anomalies will be exceptional in northeastern Sudan into Egypt’s southeast corner, and will be severe to extreme in western and southeastern Algeria and much of Niger. Warm anomalies are also forecast along a path through the Ethiopian Highlands, with some intense pockets. Warm anomalies forecast elsewhere on the continent include an exceptional pocket west of Lake Turkana in Kenya; fairly intense anomalies near Mogadishu on the coast of Somalia, in coastal Angola, and from southeastern Tanzania into northeastern Mozambique; and, primarily moderate warm anomalies in Guinea, Sierra Leone, Liberia, Zambia, northwestern Tanzania, and southern and western South Africa. Intense warm anomalies are forecast for western and northern Madagascar.

Cool anomalies are expected across the Sahel and reaching into South Sudan, where anomalies will be intense. Primarily moderate cool anomalies are forecast in pockets of eastern Uganda, northern Kenya, and western and south-central Democratic Republic of the Congo.

Central Europe will be moderately warmer than normal, with similar conditions reaching north into southern Norway. Moderate warm anomalies are also expected in central Romania, southern Italy, and much of Spain with more intense anomalies on Spain’s Mediterranean Coast and west of Madrid.

The U.S. can expect warmer than normal temperatures in the southern Ohio River Valley, the South, Southeast, and Mid-Atlantic. Anomalies will be moderate overall but severe from the Carolinas into Georgia, central Florida and the Panhandle, and southern Alabama into Mississippi. Central Colorado will be moderately warmer than the norm, as will southern Arizona. Warm anomalies are forecast for New Mexico and will reach extreme intensity in the center of the state. Intense warm anomalies are forecast for northern Alaska and moderate anomalies in the west. In Canada, warm anomalies of varying intensity are forecast for northern Quebec and Nunavut.

In Mexico, warm anomalies are expected in Baja, from southern Chihuahua south through Guadalajara, in the Yucatan, and in the southern states. Anomalies will be exceptional in Nayarit on the Pacific Coast. Intense warm anomalies are forecast in many regions of Central America, and warm anomalies of varying intensity are expected in western Cuba, Jamaica, the Bahamas, and Puerto Rico.

Conditions in much of Brazil’s eastern bulk will be warmer than normal, with anomalies reaching extreme intensity in São Paulo State. Moderate warm anomalies are expected in northwestern Venezuela; pockets of Colombia; northwestern and central Peru; surrounding La Paz, Bolivia; and northwestern Argentina. Anomalies more intense are expected in south-central Bolivia and near Copiapo, Chile. Cooler than normal conditions are expected in north-central Venezuela; Manaus, Brazil; western Loreto, Peru; spanning the northern portion of the border between Peru and Bolivia, and reaching through northern Bolivia; the Chaco Austral region of north-central Argentina; and southern Chile and Argentina.

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, 2019 which includes forecasts for October 2019 through June 2020 based on NOAA CFSv2 forecasts issued September 24 through September 30, 2019.

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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