Global Precipitation & Temperature Outlook for July 2016

Global Precipitation & Temperature Outlook for July 2016

Overview
Though some precipitation anomalies are apparent in the July forecast it is, once again, the extent and severity of heat anomalies that command our attention. (For data sources see "About this blog post" below.)

Temperature Outlook
Many hotspots forecast last month remain in this month's outlook but a few new areas are worth noting first: Abnormal to exceptionally hotter temperatures are forecast across much of northern Canada, including Yukon Territory, Northwest Territories, and western Nunavut; also, exceptional (greater than 40 years) heat anomalies are forecast for most of Japan. 

Temperature outlook for July 2016. 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.

Warm anomalies are forecast for much of the eastern United States, with exceptionally warmer temperatures expected in Florida, southern Maine, northern Michigan, and central Louisiana. Alaska and southern Arizona are also forecast to be warmer than normal.

In Mexico warmer than normal temperatures are forecast in Baja and across the Gulf of California into northwestern Sonora, central Coahuila, Jalisco, and from Oaxaca through much of the Yucatan. In western Cuba and Jamaica exceptional heat anomalies are forecast. Moderate to severe heat anomalies are forecast for Guatemala, Belize, Honduras, eastern Nicaragua, and Costa Rica. Much of the northern half of South America is forecast to experience moderate to exceptional warm anomalies.

Heat anomalies ranging from moderate to exceptional are forecast across northern Africa, coastal West Africa, and into and across southern Africa. Pockets of cool anomalies are predicted for several Central African nations. Warm anomalies are forecast for Saudi Arabia and around the Persian Gulf.

Romania, western Ukraine, and Belarus will be warmer than normal. Likewise, a vast expanse of the northern portion of European Russia is forecast to be warmer than normal, as is a large area surrounding Lake Baikal. Central Kazakhstan and Kyrgyzstan are forecast to be cooler than normal.

Moderate to exceptional heat anomalies are forecast for southern India, Sri Lanka, many parts of China, Mongolia, the Korean Peninsula, and Southeast Asia. Much of Australia - with the exception of the southern part of Western Australia - is forecast to be warmer than normal, along with South Island, New Zealand.

Precipitation Outlook
The absence of any noteworthy patches of dark red on the July precipitation map indicates that few, if any, exceptionally drier than normal (greater than 40 years frequency) areas are forecast. However, several regions can expect moderate (5-10 years) to severe (10-20 years), or in some isolated cases, extreme (20-40 years) dry anomalies. 

Precipitation outlook for July 2016. 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.

Extreme to exceptionally drier than normal conditions are forecast for the narrow southern portion of Thailand that extends into the Gulf of Thailand. Eastern Cambodia and southern Vietnam are forecast to be extremely drier than normal with surrounding areas moderately to severely drier.

Moderate to extreme dry anomalies are forecast for: Kerala, Karnataka, and Andhra Pradesh in southern India; and northwestern Ethiopia. Dry anomalies of somewhat lesser severity are forecast for: Central Russia between the Volga Uplands and the Ural Mountains; Veracruz, Mexico; eastern Ecuador extending north into Colombia and southeast into Peru; along the Amazon Basin in northern Brazil; Nevada, US; and southern Nunavut, Canada.

Wet anomalies are forecast In the United States for a northward band from Yuma, Arizona through Nevada and Utah; and in West Virginia. Elsewhere, wet anomalies also forecast for: northeastern Argentina and in Uruguay; southern Spain; the Balkans; northern Kazakhstan and across the border into Russia; central Chad; northern Somalia; northern Xinjiang, China; Shanghai, China and to the west; the Korean Peninsula; Java; and Western Australia. 

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 July 5, 2016 which includes forecasts for July 2016 through March 2017 based on NOAA CFSv2 forecasts issued June 24 through June 30, 2016.

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.