Climate

Seasonal Climate Outlook

Background

The Qatar Meteorological Department is introducing monthly and seasonal (3-month) climate outlooks for Qatar and adjoining regions, beginning April 2014. Monthly and seasonal climate forecasts are generated world wide with an underlying assumption that sea surface temperatures in global oceans, snow-cover, soil-moisture of the land surface and other such slowly varying boundary conditions determine the ensuing global and regional climate anomalies. Leading climate centers around the world use fully coupled ocean-atmosphere general circulation models for generating seasonal climate forecasts wherein both sea surface temperatures and associated atmospheric circulation co-evolve. Climate forecasts are generally in the form of anomalies from a long-term climatology as simulated in the models. Individual climate centers produce monthly/seasonal forecasts based on a large suite of simulations (generally initiated every month and extending 6 months in to the future) with different initial conditions using their global climate model and then develop an ensemble forecast product employing advanced statistical techniques.  Show Details...

World Meteorological Organization (WMO) supports and coordinates seasonal forecasts through lead centers (LC) of long-range forecasts (LRF). Korea Meteorological Administration, Seoul, maintains one such lead center. This WMO Lead Center (WMOLC) uses all available forecasts from different climate centers around the world and generates multi-model ensemble (MME) monthly and seasonal climate forecasts for the globe. Several meteorological variables are predicted which include surface temperature (2m), precipitation etc. Apart from WMOLC, other climate centers like International Research Institute for Climate and Society (IRI, New York, USA), National Centers for Environmental Prediction (NCEP/NOAA, USA), APEC Climate Center (APCC, Korea), UK Meteorological Office (UKMO, UK), ECMWF (UK), Bureau of Meteorology (BoM, Australia) etc. also produce monthly/seasonal forecasts.

In preparation of this Climate Outlook for Qatar the monthly/seasonal products generated by the WMOLC have been used. This approach takes in to account a majority of the model forecasts from the Global Producing Centers (GPCs) and combines them using ensemble mean forecast system. However, we also take in to consideration of other forecast products while generating the outlook for the regional temperature and precipitation anomalies for the coming month and season.

The skill of WMOLC ensemble mean forecast products varies from month to month and from one meteorological variable to the other. Generally the skills of temperature forecasts are larger compared to the precipitation forecasts. This disparity in skills between temperature and precipitation forecasts is not unique to this region and is the case globally. The correlation skills estimated based on retrospective (hindcast) forecasts during the past 30 years of MME prediction system are in the range of 0.4-0.6 during different months in the year and for the surface temperatures over this region. These are considered reasonably high compared to the skills observed in other parts of the world.

The current Climate Outlook for Qatar is mainly for monthly/seasonal mean temperature forecast. The reason for the initial focus on temperatures is both due to higher skill and its prime relevance to climate sensitive activities in the national context. With further review of predictive skill and demand of user sectors, the scope of the seasonal climate outlooks can be expanded to cover more features of relevance to this region such as the probability of high wind events, exceedance of certain temperature thresholds etc.

Two types of forecast products are generated by climate centers. One is the probabilistic forecast where the seasonal climate anomalies are predicted to be in one of the three categories (below normal, normal and above normal) and the probability of predicted values falling in these categories is estimated. The other is the deterministic forecast where the magnitude of anomalies is estimated for the ensuing month and the season using different statistical techniques. This outlook uses the forecasts estimated based on simple ensemble mean after correcting the biases in each of the participating models.

Seasonal Outlook for March-April-May 2017

Global

The State of the Climate Summary Information is a synopsis of the collection of national and global summaries released each month. As per recently released 'Global Summary Information- January 2017' by the US National Oceanic and Atmospheric Administration (NOAA), The globally averaged temperature over land and ocean surfaces for January 2017 was 0.88°C above the 20th century average of 12.0°C. This was the third highest January temperature in the 1880–2017 record, behind 2016 (highest) and 2007 (second highest). Also, January had the record low Arctic and Antarctic sea ice extents since observations began in 1979 (http://www.ncdc.noaa.gov/sotc).

The latest forecasts available from the World Meteorological Organization Lead Center for Long-Range Forecast (WMOLC LRF) for the coming season (March-April-May) are nearly similar to those that were issued last month for February-March-April season, excepting the temperature anomalies over the central and eastern equatorial Pacific that are projected to be more positive compared to the near normal temperatures predicted last month. The positive temperature anomalies predicted last month over southern parts of Asia will continue to prevail for the season March-April-May 2017 (Fig.1). Temperature forecasts show more positive anomalies over Australia compared to the forecasts issued last month. Forecasts also indicate high probability of above normal temperatures in the north Indian Ocean mainly over Arabian Sea and Bay of Bengal and adjacent land areas including maritime continent. They also show higher probabilities of warmer than normal temperatures over western Pacific Ocean. Enhanced probability of above normal temperature is predicted over equatorial Atlantic, Mediterranean and in most parts of eastern Africa. Near normal precipitation is predicted for the maritime continent. Weakened probability for below normal precipitation is predicted for the central equatorial Pacific east of the dateline and parts of equatorial Indian Ocean compared to last month. The changes in the forecast probabilities of temperature and rainfall over the central and eastern equatorial Pacific Ocean reflect the evolving changes in the ENSO state compared to last month.

ENSO

El Nino Southern Oscillation (ENSO) is an Ocean-Atmospheric Phenomenon in the Pacific Ocean that impacts the climate in different parts of the globe. The warm ENSO condition is known as El Nino and the cold ENSO condition is known as La Nina. As per the IRI, the tropical Pacific SST anomaly during mid-February 2017 was close to 0.0°C indicating ENSO-neutral conditions. The suite of ENSO predictions from different models being used at IRI indicates SSTs to remain neutral through May 2017, with a chance for El Nino development later in the year (http://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/).

The latest ENSO update from CPC/NCEP also indicates the presence of ENSO-neutral conditions with equatorial sea surface temperatures (SSTs) being near-average across the central and east-central Pacific and above-average in the eastern Pacific Ocean. Their update also says that ENSO-neutral conditions are favored to continue through at least the Northern Hemisphere spring 2017. (http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf).

Regional

Probabilistic MME forecasts (based on 11 global models) from WMOLC shows that temperatures during March, 2017 are likely to be above normal with probabilities in the range of 50-60% across the GCC region. However, forecasts indicate enhanced probability for seasonal (March-April-May) temperatures to be above normal (60-70% probability) in most parts of GCC with relatively higher probabilities over southern parts (Fig.2). Probabilistic MME seasonal (MAM) forecasts of temperatures from IRI are slightly higher compared to the WMOLC combined forecasts (http://iri.columbia.edu/our-expertise/climate/forecasts/seasonal-climate-forecasts/).

The deterministic MME forecasts (based on 12 models from WMOLC) indicate above normal temperatures in the range of +0.5°C to 1.0°C over most of the GCC region in March 2017. Temperature forecasts for the entire season (MAM) are showing similar temperature anomalies but over a relatively smaller area in GCC. The temperature anomalies for the State of Qatar are expected to be in the range of +0.25°C to 0.5°C for March 2017 and during MAM season (Fig. 3) as well. Forecasts from other climate centers are generally in agreement with WMOLC outlook for Qatar and the GCC.

Model forecasts from WMOLC indicate near normal precipitation during March and the season (MAM) as well over the GCC region.

Climate for State of Qatar in February 2017

The monthly mean, minimum and maximum temperatures recorded in Doha in the month of February are (18.5°C, 15.4°C, 21.7°C) respectively. These are deviate by (-0.1, +0.7, -1.7°C) from their respective long-term Climatological values.

Fig 1. Probabilistic MME forecast from WMO LC LRF: 2m Temperature and precipitation


Fig 2. Probabilistic MME forecast from WMO LC LRF : 2m Temperature

Fig 3. Deterministic MME forecast from WMO LC LRF : 2m Temperature