Global Precipitation & Temperature Outlook January 2019

Global Precipitation & Temperature Outlook January 2019

2 January 2019

OVERVIEW
The January Outlook indicates much wetter than normal conditions forecast for southern China through the Pearl River Basin encompassing the Pearl’s northern tributaries; and, oceans away in Uruguay. Temperatures in Northeast China are expected to be exceptionally warmer than usual, anomalies with a return period of 40 or more years.

PRECIPITATION OUTLOOK
Wet anomalies are forecast in southern China from Guangxi through northern Guangdong, stretching across northern tributaries of the Pearl River and veering northeast through Zhejiang. Conditions could reach exceptional intensity (40+ years return period). Moderate dry anomalies are forecast in a far-reaching band across northern China from the Taklamakan Desert in the west through central Inner Mongolia, and stratified bands in central Mongolia. Some drier than normal pockets are also forecast in Japan.

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.

Southeast Asia is expected to be moderately to severely wetter than normal and anomalies will be widespread in Thailand. Relatively normal precipitation is forecast for Malaysia and Indonesia. In Australia, moderate to severe dry anomalies are forecast in southeastern Queensland west of Bundaberg.

Widespread, primarily mild to moderate wet anomalies are expected to trace a vast, horizontal path in Russia from European Russia through the eastern edge of the Central Siberian Plateau, while moderate dry anomalies are forecast for northern Far East Russia. Some wet anomalies are forecast for Central Asia, generally mild across northern Kazakhstan and pockets elsewhere in the region, with moderate to severe anomalies in eastern Kyrgyzstan and northern Afghanistan. Moderate dry anomalies are forecast on the Arabian Peninsula, with relatively normal precipitation conditions elsewhere in the Middle East.

In Europe, some mild to moderate wet anomalies are expected in the Baltics, Belarus, western Ukraine, and pockets of Germany, Poland, and Czech Republic. Southeastern Spain will be moderately drier than normal.

In Africa, wetter than normal conditions are forecast around the Gulf of Guinea from coastal Ghana through western Cameroon, and in northern Somalia. Other areas of wet anomalies include: southeastern Ethiopia, north-central Kenya, western Republic of the Congo, and pockets in western Democratic Republic of the Congo (DRC). Morocco will be moderately drier than normal.

In South America, primarily moderate dry anomalies are forecast in northern Colombia, Venezuela’s northern half, and into Guyana but conditions may be severe in Venezuela between Lake Maracaibo and Caracas. Moderate to severe anomalies are also expected in eastern Brazil from Bahia to São Paulo. Much wetter than normal conditions are forecast in Brazil’s southernmost state of Rio Grande do Sul and in neighboring Uruguay and anomalies could reach exceptional intensity. Northeastern Argentina will also be wetter than normal though conditions are not expected to be as intense as in Uruguay. Elsewhere on the continent, regions forecast to be wetter than normal include: Brazil’s northeastern coast from Amapá through Ceará; and, a path from southern Colombia winding through north-central Peru, westernmost Brazil, and into central Bolivia.

Central America will see some pockets of drier than normal conditions. Moderate wet anomalies are forecast for northeastern and central Mexico, downgrading to mild in western Texas.

Elsewhere in the US, mild to moderate dry anomalies are forecast for the western portion of the Ohio River Basin, northern Michigan, and the Northern Plains States and northern Rockies. Moderate dry anomalies are forecast for northern Quebec, Canada, and southern Alberta. Wetter than normal conditions are forecast for central Canada and Canada’s Pacific Coast.

TEMPERATURE OUTLOOK
A vast block of deep red on the Temperature map below calls attention to a forecast of exceptionally warmer than normal conditions in China west and north of the Yellow Sea, reaching through Mongolia’s eastern half as well as into Primorsky, Russia on the Sea of Japan. Severe to exceptional warm anomalies are also forecast for northwestern China (Xinjiang), Yunnan in the south, and Taiwan. Conditions on the Korean Peninsula will be only slightly less intense, ranging from severe to extreme. Primarily severe warm anomalies are forecast for Japan with some extreme pockets.

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.

Likewise, severe warm anomalies are expected in many parts of Southeast Asia as well as some large extreme pockets. Intense warm anomalies will also dominate much of Indonesia, Malaysia, and the Philippines, and will be exceptional and widespread in Sumatra, Java, eastern Borneo, and northern Philippines.

Many parts of Australia will also be warmer than normal with exceptional anomalies in the Great Sandy Desert in northern Western Australia and the Tanami Desert in central Northern Territory. Moderate to extreme warm anomalies are forecast for the southeastern quadrant of the country, with severe anomalies tracing the southeastern coast and Tasmania, and a vast pocket of extreme intensity in the Diamantina River region of southwestern Queensland. Primarily severe warm anomalies are forecast for North Island, New Zealand and moderate anomalies in South Island.

In South Asia, conditions in India will be moderately warmer than normal but severe anomalies are expected in Karnataka and also in Sri Lanka. Cooler than normal temperatures are forecast for a pocket along the northern border of Uttar Pradesh and Bihar, India just south of Nepal. Moderate to severe warm anomalies are forecast for Pakistan and Afghanistan, and severe anomalies will be widespread in northern Afghanistan.

Similar conditions are expected in Central Asia and a vast stretch across southern Russia. Anomalies could reach exceptional intensity around Lake Baikal.

In the Middle East, intense warm anomalies are forecast for Yemen’s western third and the southeast, and Iran’s southern provinces. Moderate to severe warm anomalies are forecast for much of Saudi Arabia.

In Europe, warm anomalies are expected in Northern, Central, and Eastern Europe and will be severe in southern Norway, Denmark, Netherlands, northern Germany, Poland, and western Ukraine. Relatively normal temperatures are expected in Mediterranean Europe.

Much of northern Africa will also be relatively normal. Elsewhere on the continent, severe to exceptional warm anomalies are forecast for: the Horn of Africa, Madagascar, South Africa, Lesotho, Cameroon, central Nigeria, pockets around the Gulf of Guinea, and Burundi. Regions with a forecast of warm anomalies of generally lesser intensity include: Sudan, Republic of the Congo, western and southern DRC, Angola, northern Zambia, and Tanzania. Cool anomalies are forecast for southwestern Ethiopia, northeastern Kenya, and a pocket of north-central DRC.

In South America, warm anomalies of varying intensity are forecast in Brazil from Rio Grande do Norte in the east to Rio Grande do Sul in the South. Anomalies will be exceptional along the coast around Rio de Janeiro through São Paulo. Conditions will also be much warmer than normal in western Bolivia along a path through northwestern Argentina. Severe warm anomalies will trace a path from northern Ecuador though western Peru and northern Chile. Temperatures are expected to be moderately warmer than normal in Colombia and pockets of Venezuela and central and western Brazil. Areas of cool anomalies include central Brazil and Chilean Patagonia.

In Mexico and Central America, severe warm anomalies are forecast for Nayarit, Mexico; southern Guatemala, Costa Rica, and Panama.

While the southern half of the US will see normal temperatures, widespread warm anomalies are forecast for much of the northern half from central California through the Great Lakes. The southern reaches of these warm anomalies will be moderate but conditions in the Northern Plains States and Pacific Northwest will be severe, and an extreme patch is forecast in north-central Montana. Across the border in Canada the extent of warm anomalies will increase, covering a vast area encompassing all provinces west of Quebec. Anomalies are expected to be extreme to exceptional in Alberta and 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 January 2, 2019 which includes forecasts for January 2019 through September 2019 based on NOAA CFSv2 forecasts issued December 25 through December 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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