Consolidated Seasonal Rainfall Guidance for Africa, November 2013 Initial ConditionsIssued 7 November 2013 • Forecast maps • Forecast Background • ENSO update • Current State of the global climate • SST Forecasts • Summary
Methodology • The forecasts are subjectively derived from canonical correlation analysis (CCA) seasonal forecast runs, the NCEP CFS, the National Multimodel Ensemble (NMME) forecasts, and the International Multimodel Ensemble (IMME) forecasts • Polygons are drawn for areas, where there is an agreement between the models to tilt the odds to favor one category over another. Preference is sometimes given to the CCA when skill is moderate to high. • The NMME models include: the NOAA CFS, the Canadian models, NOAA GFDL, NCAR, NASA • The IMME models include: the ECMWF, the UK MO, and Meteo France • Forecasts are expressed in probabilistic terms to convey uncertainty.
Seasonal Rainfall Guidance for Africa, Oct IC, Issued 7 Nov 2013, Valid Nov 2013 – May 2014 Based on an assessment of CCA forecasts, CFSv2, and NMME, the use of climatology is suggested for Africa from zero to 4 months lead.
CPC ENSO Update • CPC ENSO Alert System Status: Not Active (updated 7 November 2013) • Synopsis:ENSO-neutral is expected through the Northern Hemisphere Spring 2014 http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.shtml
Current State of the Global Ocean Last Month SST Anomaly (top) for October 2013 and Tendency (bottom) for October minus September Positive SST anomalies were observed over parts of the Indian Ocean and the northern Pacific Ocean. SST was slightly below normal across the equatorial eastern Pacific. Above-average SST persisted across the northern Atlantic. SST tendency was positive across portions of equatorial eastern Pacific. Positive SST tendency was observed over the northern Indian Ocean.
Current State of the Global Ocean Last Week Weekly SST Anomaly 27 Oct – 02 Nov 2013 and Tendency for 27 Oct – 02 Nov 2013 minus 20 – 26 Oct 2013 SST was below normal in the equatorial eastern Pacific. Positive SST anomalies persisted over many parts of the northern Atlantic. Positive SST anomalies were present over much of the Indian Ocean and parts of the western Pacific. SST tendency was negative over the North Atlantic Ocean SST tendency was positive over parts of the Indian Ocean
OLR Anomaly, October 2013 Negative OLR anomalies (enhanced convection and precipitation, blue shading) were observed over portions of West Africa, the Greater Horn of Africa and near the Mozambique Channel in Africa, over much of India and western Pacific extending into Indonesia, Papa New Guinea and western Australia, and over Bolivia and portions of Brazil. Precipitation was suppressed (orange-red shading) over portions of the Lake Victoria and southern Africa regions in Africa, many parts of the Indian Ocean, eastern Australia and over the Central Pacific Ocean.
Low Level 850 mb Wind Anomaly Stronger than normal cross-equatorial flow was observed near the Horn of Africa and India. Anomalous cyclonic circulation was present over western Pacific. Westerly anomalies persisted across Equatorial eastern Pacific.
Monitoring the Indian Ocean Dipole (IOD) The IOD index remains neutral.
Monitoring the Madden Julian Oscillation Time Over the last few days, the MJO index emerged in Phase 8 and has exhibited an eastward propagation . The ensemble GFS indicates a gradual weakening MJO signal during the upcoming weeks. Longitude
Summary of State of the Global Climate in October 2013 • Neutral ENSO state continued to prevail in October. Equatorial sea surface temperatures (SST) anomalies continued to be negative across the eastern Pacific and positive over parts of the western Pacific. • SST was above-average over the northern Atlantic and portions of the Indian Ocean. The IOD index remained near neutral during October 2013. • Precipitation was above average over parts of West Africa, the Greater Horn of Africa, and along the Mozambique Channel. Precipitation was also enhanced over much of India and the western Pacific, as well as central South America. In contrast, precipitation was suppressed in the vicinity of Lake Victoria and parts of southern Africa. Precipitation was also suppressed over southeastern Indonesia.
IRI/CPC NINO3.4 Forecast Plume • Most models predict ENSO-neutral continuing into Northern Hemisphere spring 2014. • The consensus forecast favors ENSO-neutral through the Northern Hemisphere Spring 2014
Global SST Outlook: NCEP CFS.v2 Forecast Initial Conditions 22 – 31 October 2013 Nov 2013-Jan 2014 Feb-Apr 2014 Caution: Ocean areas with skill less than 0.3 are shaded in gray Dec 2013-Feb 2014 Mar-May 2014 Jan 2013-Mar 2014 CFS.v2 predicts neutral ENSO conditions to persist through the northern hemisphere fall season. Additional forecast resources are found here: http://www.cpc.ncep.noaa.gov/products/african_desk/cpc_intl/index.shtml http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/
Global SST Outlook: NMME (left) and IMME (right) NDJ NDJ DJF DJF http://www.cpc.ncep.noaa.gov/products/NMME/seasanom.shtml
Global Precipitation Outlook: NMME (left) and IMME (right) NDJ NDJ DJF DJF http://www.cpc.ncep.noaa.gov/products/NMME/seasanom.shtml
IOD Outlook (source: Australian Bureau of Meteorology) The IOD signal is expected to remain week through the Northern Hemisphere Winter.
Summary • SST predictions favor ENSO-neutral to continue into northern hemisphere Spring 2014. • Precipitation forecast skill is very low and therefore the use of climatology is suggested for Africa. • Additional forecast resources can be found here: http://www.cpc.ncep.noaa.gov/products/african_desk/cpc_intl/index.shtml http://www.cpc.ncep.noaa.gov/products/NMME/ http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/ http://iri.columbia.edu/our-expertise/climate/forecasts/seasonal-climate-forecasts/