Global Precipitation & Temperature Outlook March 2018

Global Precipitation & Temperature Outlook March 2018

2 March 2018

OVERVIEW
The March Outlook indicates that East Africa, Southeast Asia, and Paraguay will be significantly wetter than normal. A vast stretch of much warmer than normal conditions is forecast from West Africa leading across Mediterranean Africa, through the Levant, and from northern Iran through Central Asia across much of northern China into Mongolia.

PRECIPITATION OUTLOOK
A large blue/green block in East Africa on the precipitation map below calls attention to a forecast of significantly wetter than normal conditions, with a return period of 10 to 40 years, in Kenya, Uganda, Tanzania, southern Ethiopia, and southern South Sudan. Some severe dry anomalies are forecast for western Gabon, nearby in southern Republic of the Congo, and into far western Democratic Republic of the Congo. Relatively moderate dry anomalies are expected scattered across northern Africa and in Madagascar's southern half.  

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.

In the Middle East, some moderate dry anomalies are forecast for Jordan, northern and southwestern Saudi Arabia, and north-central Iran.

Many parts of Europe should see wetter than normal conditions. Wet anomalies may be severe, conditions normally seen only once every 10 to 20 years, in western Spain and in Portugal. Primarily moderate wet anomalies are forecast for much of France, Belgium, and the United Kingdom, and parts of Central and Eastern Europe including Switzerland, Austria, Hungary, Slovenia, Croatia, Bosnia and Herzegovina, Serbia, and eastern Ukraine.

Primarily moderate wet anomalies are also forecast in a vast stretch from the Caucasus across northern Kazakhstan and Russia to Russia's Far East, where anomalies may be more intense. Kyrgyzstan and Tajikistan may be drier than normal, with some severe conditions.

Moderate dry anomalies are forecast for southern Mongolia into northern China, and wet anomalies ranging from moderate to extreme are forecast for Tibet, Sichuan, and Guangxi. Intense wet anomalies are expected to blanket much of Southeast Asia, particularly Thailand, Laos, Cambodia, and Vietnam, and will be exceptional in some regions. Conditions will be moderately wetter than normal in many parts of Indonesia and Papua, and in northern Australia.

In the West, moderate to severe wet anomalies are forecast for the US Northern Plains and Northern Rockies trailing into Canada. Conditions along the Gulf of Alaska are forecast to be drier than normal. In South America, Paraguay stands out with a forecast of moderate to severe wet anomalies throughout the country, and anomalies may be extreme as they reach into northern Argentina, and in south-central Bolivia. Primarily moderate dry anomalies are forecast for parts of Ecuador, Peru, northwestern Argentina, and Uruguay. 

TEMPERATURE OUTLOOK
As is obvious in the temperature map below, much warmer than normal temperatures are forecast across a vast swath from West Africa leading across Mediterranean Africa, through the Levant, Turkey, the Caucasus, and from northern Iran through Central Asia across much of northern China into Mongolia. Anomalies will be exceptional in many regions.

Exceptionally cooler than normal conditions are forecast for eastern Central African Republic, South Sudan, west-central Kenya, and central Democratic Republic of the Congo. Cooler than normal temperatures are also expected in southern Kenya, eastern Uganda, central Tanzania, northwestern Angola, and northern Botswana.

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.

In Europe, moderate warm anomalies are forecast for the Iberian Peninsula, southern France, and Switzerland, with more severe warm anomalies in southern Italy and parts of the Balkans. Conditions may be exceptional in Sicily. Northern UK and Northern Europe may be somewhat cooler than normal.

Moderate to occasionally extreme warm anomalies are forecast in many parts of Asia including Pakistan, northern India, much of eastern China, the Korean Peninsula, Japan, and far eastern Russia. Indonesia and Papua will be moderately warmer than normal with some areas more severe.

Temperatures near Brisbane, Australia are forecast to be extremely warmer than normal.

Much of Canada's eastern half is forecast to be moderately warmer than normal, reaching into the US Northeast. Moderate warm anomalies are expected in eastern New Mexico and eastern Colorado. Warm anomalies will be severe in north-central Mexico and extreme in Nayarit and northern Jalisco. 

In South America, moderately warmer conditions will prevail in many regions, with more severe anomalies in northwestern Amazonas and Minais Gerais, Brazil, as well as in western Bolivia. Areas of moderate warm anomalies include: much of Brazil north of São Paulo, southern Guyana, southern Colombia, eastern Ecuador, Peru, Uruguay, and eastern Argentina. Moderately cooler than normal conditions are forecast for Paraguay.

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 March 2, 2018 which includes forecasts for March 2018 through November 2018 based on NOAA CFSv2 forecasts issued February 22 through February 28, 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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