Global Precipitation & Temperature Outlook for October 2016

October 4, 2016

Overview
The October Outlook indicates large expanses of exceptionally warmer than normal temperatures from Quebec into Newfoundland and Labrador, Canada, and coastal West Africa, along with significant warm anomalies elsewhere throughout the world as detailed below. October is forecast to be exceptionally wetter in the Kimberly region of Western Australia. (For data sources see "About This Blog Post" below.)

Temperature Outlook
The darkest red spots on the temperature map below indicate a forecast of exceptionally warmer temperatures, beyond a 40-year expected frequency. Notice the wide belt of dark red across central Quebec, Canada extending into Newfoundland and Labrador. Also notable are the reds and oranges in the surrounding expanse indicating severe to extreme (10-40 years) warm anomalies for much of eastern Canada and the northeastern US.

Primarily moderate (5-10 years) warm anomalies are expected in the eastern US, reaching from Minnesota through the Atlantic Seaboard and south to the Gulf Coast. However, more severe warm anomalies are forecast in the Northeast, in northern Michigan, and in Michigan's Upper Peninsula. Alaska, too, is expected to be warmer than normal.

Extreme to exceptional (20 to beyond 40 years) warm anomalies are predicted in Mexico's western state of Nayarit north of Puerto Vallarta, and warm anomalies of varying severity are forecast for the Yucatan Peninsula, Central America, and the Caribbean. In South America warm anomalies trace a path from Northeast Brazil up through Amapá, and from western Bolivia south through Chile.

Western Europe is forecast to be warmer than normal, especially Spain. Moderate to exceptional warm anomalies are expected in a vast expanse of Russia from European Russia into the western portion of the Central Siberian Plateau.

In Africa exceptional warm anomalies are forecast along coastal Western Africa, trailing down to northern coastal Angola. Warm anomalies of varying severity are expected in northwestern Africa, and scattered across southern Africa.

Southern India, Sri Lanka, Bangladesh, Myanmar, Southeast Asia, Malaysia, and parts of Indonesia are expected to experience moderate to exceptional warm anomalies.

A few areas of blues and greens stand out on the temperature map, indicating a forecast of cooler than normal temperatures, particularly Bolivia and South Sudan.

Precipitation Outlook
The October precipitation map, below, clearly shows some dry anomalies in yellow and orange, though few are particularly severe. Severe to exceptional wet anomalies - deeper shades of blue on the map - are forecast for several regions.

Severe to exceptional dry anomalies are forecast for Guinea-Bissau and western Guinea; west of Lake Baikal in Irkutsk, Russia; along Ecuador's coast; and along a path from Lima, Peru past La Paz, Bolivia. Dry anomalies of lesser severity are expected in Turkey and western Georgia; the Middle East into Central Asia; the Central Siberian Plateau; and Quebec, Canada near the Gulf of St. Lawrence.

The following regions are forecast to be exceptionally wetter than normal: the Cordillera Central Mountains in Colombia and Ecuador; in Peru's northern Cordillera Oriental Mountains and between the Rios Marañón and Ucayali; Gabon; western Mongolia; northern Xinjian, China; Java; and the Kimberly region of Western Australia.

Wet anomalies are also forecast for: the conjoined borders of Montana, North Dakota, and Saskachewan; northern Bolivia; Ireland; Andhra Pradesh, India; southern Sumatra, Borneo, and Papua; and much of northern Australia and southern Victoria.

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, 2016 which includes forecasts for October 2016 through June 2017 based on NOAA CFSv2 forecasts issued September 24 through September 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.