Global Precipitation & Temperature Outlook for November 2017

3 November 2017

Overview
South Africa stands out in the November Outlook with a forecast of exceptionally hotter than normal temperatures. Much of Asia, Indonesia, and the southern and eastern US are expected to be warmer than normal.

Precipitation Outlook
Drier than normal conditions are forecast along a path tracing the Andes in South America from Colombia through Ecuador, Peru and Bolivia, and are expected to be extreme in western Ecuador and other points along the path. Severe to extreme dry anomalies are predicted along the Gulf of Mexico from Veracruz to Laguna de Términos in the Bay of Campeche, then turning south through Guatemala, Honduras, and into Nicaragua.

Moderately drier than normal conditions are forecast for a large block reaching from north-central Mexico into western Texas, the Texas Panhandle, and New Mexico. Moderate dry anomalies are expected in much of Florida, winding up the coast through South Carolina. Dry anomalies may reach severe intensity west of Lake Okeechobee, Florida.

In the Mideast and Central Asia, conditions are expected to be moderately drier than normal in: Saudi Arabia, Iraq, Iran, central Turkmenistan, eastern Afghanistan, Tajikistan, and northern Pakistan. Severe dry anomalies are forecast for western Georgia and along the Black Sea coast into Turkey.

Moderate to extreme dry anomalies are forecast for western Tasmania, Australia, and along western Victoria's coast.

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… — 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.

Wetter than normal conditions are expected in some central and southern African nations including South Sudan, western Ethiopia, northern Central African Republic, Equatorial Guinea, eastern Democratic Republic of the Congo, eastern Uganda, central Somalia, eastern Tanzania, northern Mozambique, Malawi, and southwestern Namibia. Anomalies may reach extreme intensity in south Sudan and Equatorial Guinea.

Moderate to extreme wet anomalies are forecast in Russia's far northeast and in North Sumatra province, Indonesia. Moderate wet anomalies are predicted in southern Laos, eastern Thailand, southern Vietnam, western Hainan, Sri Lanka, southwestern Australia, and northeastern New South Wales, Australia.

Primarily moderate wet anomalies are forecast for the US Northern Prairie states reaching into Canada, the Ohio River Valley, and Central California. Moderate to exceptional wet anomalies are forecast for northern Alaska. In South America wet anomalies of varying intensity are expected in: southern Venezuela into Colombia and Brazil; central Colombia; central Brazil; northern Bolivia; Paraguay; and central Chile into Argentina.

Temperature Outlook
As seen in the temperature forecast map below, South Africa jumps out in dark red, indicating a forecast of exceptionally hotter than normal temperatures. Other regions with a forecast of exceptional warm anomalies include: northwestern Alaska; central-Pacific Mexico fanning inland from Puerto Vallarta and leading northeast nearly to the US border; pockets in the eastern Andes ranges through Peru and Bolivia; southwestern Namibia; southwestern Yemen; pockets throughout Iran; eastern Tajikistan; pockets in western China; and northern Sumatra.

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… — 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.

Much of the southern and eastern US will be warmer than normal, with moderate to extreme warm anomalies reaching from Texas to Maine. Warm anomalies of similar intensity are forecast for a vast stretch of western Russia and far northeastern Russia. As previously mentioned, much of Asia and Indonesia are also expected to be warmer than normal, along with Saudi Arabia, Iraq west of the Euphrates, northeastern Brazil, and southern Mexico from the Gulf of Tehuantepec to the Gulf of Mexico.

Exceptionally cooler than normal temperatures are forecast for South Sudan, and cool anomalies of varying intensity are expected in eastern Central African Republic, central Democratic Republic of the Congo, eastern Uganda, southern Tanzania, and central Mozambique. Warm anomalies are expected around the Gulf of Guinea and may be extreme in Benin and southern Nigeria.

In the West, moderate cool anomalies are forecast across the Canadian Plains provinces and in eastern Bolivia.

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, 2017 which includes forecasts for November 2017 through July 2018 based on NOAA CFSv2 forecasts issued October 25 through October 31, 2017.

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.