Regional Rainfall Forecast maps Summary Consolidated Seasonal Rainfall Guidance for Global Tropics, May 2015 Initial Conditions Issued 14 May 2015 Forecast Background ENSO update Current State of the global climate SST Forecasts Regional Rainfall Forecast maps Summary

CPC ENSO Update CPC ENSO Alert System Status: El Niño Advisory Synopsis: There is an approximately 90% chance that El Niño will continue through Northern Hemisphere summer 2015, and a greater than 80% chance it will last through 2015. (Updated on May 14, 2015) 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 April 2015 and Tendency (bottom) for April 2015 minus March 2015 Positive SST anomalies were observed across much of the Indian Ocean. Equatorial SSTs were above average across the eqauaterial central and eastern Pacific. SST tendency was positive across the western Indian Ocean. Changes in equatorial SST anomalies were positive across the equatorial eastern Pacific.

Current State of the Global Ocean Last Week Weekly SST Anomaly 3 – 9 May 2015 and Tendency for 3 – 6 May 2015 minus 26 Apr - 2 May 2015 Positive SST anomalies were present over much of the Indian Ocean. SST was above- average across the equatorial central and eastern Pacific. SST tendency was negative over the western Indian Ocean.

OLR Anomaly, April 2015 Negative OLR anomalies (enhanced convection and precipitation, blue shading) was observed over the Greater Horn of Africa and the Lake Victoria regions. Convection was also enhanced over Indonesia, much of Australia, equatorial central Pacific, and parts of South America. Precipitation was suppressed (orange-red shading) over many places in the Gulf of Guinea and Central Africa countries, southeastern Africa, the Maritime Continent, and western Pacific Ocean. .

Low Level 850 mb Wind Anomaly Anomalous low-level (850-hPa) westerly winds were located over the western and central equatorial Pacific. Anomalous anti-cyclonic circulation prevailed over the northern and West Africa.

Upper Level 200 mb Wind Anomaly Anomalous upper-level (200-hPa) easterlies were observed across equatorial central and eastern Pacific.

Monitoring the Madden Julian Oscillation The RMM MJO index indicated an incoherent signal during the past 7 days (left panel). The GFS ensemble RMM Index forecasts depict week signal over the coming two weeks (right panel). 8

Evolution of Indian Ocean SST Indices The Indian Ocean Dipole (IOD) showed positive values in late April and early May, with the latest weekly index value as of 10 May 2015 is 0.15 °C.

Summary of State of the Global Climate in April 2015 El Niño conditions are present. The most recent Ocean Nino Index (ONI) value (February – April 2015) is 0.6oC. Positive sea surface temperature (SST) anomalies continued across the central and eastern Pacific. Above-average SSTs were observed across much of the Indian Ocean. The Indian Ocean Dipole (IOD) positive values in late April and early May. Enhanced precipitation was observed over the Greater Horn of Africa and the Lake Victoria regions. Convection was also enhanced over Indonesia, much of Australia, equatorial central Pacific, and parts of South America. Convection was suppressed over many places in the Gulf of Guinea and Central Africa countries, southeastern Africa, the Maritime Continent, and western Pacific Ocean.

Eq. Subsurface temperature Anomalies Nino region SST departures The latest weekly SST departures : Recently, negative anomalies have increased at depth in the western Pacific. Niño 4 0.9ºC Niño 4 = 1.2ºC Niño 3.4 = 1.0ºC Niño 3 = 1.2ºC Niño 1+2 = 2.3ºC Niño 3 0.9ºC Niño 1+2 0.5ºC

IRI/CPC NINO3.4 Forecast Plume Season La Niña Neutral El Niño AMJ 2015 ~0% 5% 95% MJJ 2015 7% 93% JJA 2015 10% 90% JAS 2015 1% 89% ASO 2015 13% 86% SON 2015 2% 85% OND 2015 15% 83% NDJ 2015 3% 82% DJF 2015 17% 80% The majority of the models indicate Niño 3.4 SST anomalies will remain greater than or equal to +0.5C through the end of 2015.

Global SST Outlook: NCEP CFS Global SST Outlook: NCEP CFS.v2 Forecast Initial Conditions 3 – 12 May 2015 Jun - Aug 2015 Sep - Nov 2015 Caution: Ocean areas with skill less than 0.3 are shaded in gray Jul - Sep 2015 Oct - Dec 2015 Aug - Oct 2015 CFS.v2 predicts higher than normal SST across equatorial central and eastern Pacific Ocean. Additional forecast resources are found here: http://www.cpc.ncep.noaa.gov/products/african_desk/cpc_intl/index.shtml http://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/glbSSTe3SeaMask.html

Global SST Outlook: NMME (May 2015 Initial Conditions) Jun - Aug 2015 Jul - Sep 2015 NMME models predict higher than normal SST across the equatorial central and eastern Pacific Ocean. Aug - Oct 2015 Sep - Nov 2015

IOD Outlook (source: Australian Bureau of Meteorology) The average Model outlooks suggest that the Indian Ocean dipole (IOD) will remain near average through the northern hemisphere summer 2015.

Rainfall Guidance, Africa: NMME, Precipitation Skill Masked Std Rainfall Guidance, Africa: NMME, Precipitation Skill Masked Std. Anomalies, (01 – 08 May 2015 IC) Gray shade indicates areas where skill is lower than 0.3. Jun - Aug 2015 Jul – Sep 2015 The forecasts call for climatology over much of Africa. There is a slight to moderate tilt in the odds to favor below-average rainfall over portions of the Gulf of Guinea countries in Jun to Aug and Jul to Sep seasons. In contrast there a slight tilt in the odds to favor above-average rainfall over portions of the Sahel region and Somalia. Aug – Oct 2015 Sep – Nov 2015 Individual model forecasts can be found here: http://www.cpc.ncep.noaa.gov/products/international/nmme/nmme1.shtml

(01 – 08 May 2015 IC) Jun - Aug 2015 Jul – Sep 2015 Aug – Oct 2015 Rainfall Guidance, CAM and Caribbean: NMME, Precipitation Skill Masked Std. Anomalies, (01 – 08 May 2015 IC) Gray shade indicates areas where skill is lower than 0.3. Jun - Aug 2015 Jul – Sep 2015 The forecasts call for a slight to moderate tilt in the odds to favor below-average rainfall over portions of Central America and the Caribbean. Aug – Oct 2015 Sep – Nov 2015 Individual model forecasts can be found here: http://www.cpc.ncep.noaa.gov/products/international/nmme/nmme1.shtml

(01 – 08 May 2015 IC) Jun - Aug 2015 Jul – Sep 2015 Aug – Oct 2015 Rainfall Guidance, South America: NMME, Precipitation Skill Masked Std. Anomalies, (01 – 08 May 2015 IC) Gray shade indicates areas where skill is lower than 0.3. Jun - Aug 2015 Jul – Sep 2015 The forecasts call for a slight to moderate tilt in the odds to favor below average rainfall along the northern coast of South America. In contrast, there is a slight to moderate tilt in the odds to favor above-average rainfall over portions of Bolivia, Paraguay and Brazil. Aug – Oct 2015 Sep – Nov 2015 Individual model forecasts can be found here: http://www.cpc.ncep.noaa.gov/products/international/nmme/nmme1.shtml

(01 – 08 May 2015 IC) Jun - Aug 2015 Jul – Sep 2015 Aug – Oct 2015 Rainfall Guidance, Central Asia: Precipitation Skill Masked Std. Anomalies, (01 – 08 May 2015 IC) Gray shade indicates areas where skill is lower than 0.3. Jun - Aug 2015 Jul – Sep 2015 The forecasts call for climatology over much of Central Asia, except for a slight to moderate tilt in the odds to favor above average rainfall over Iran and Afghanistan. In contrast, there a slight tilt in the odds to favor below-average rainfall over portions of India and Pakistan. Aug – Oct 2015 Sep – Nov 2015 Individual model forecasts can be found here: http://www.cpc.ncep.noaa.gov/products/international/nmme/nmme1.shtml

Summary El Niño conditions are present. Above-average Sea surface temperatures (SST) was observed over the central and eastern Pacific Ocean. Positive SST anomalies were observed over much of the Indian Ocean. There is an approximately 90% chance that El Niño will continue through Northern Hemisphere summer 2015, and a greater than 80% chance it will last through 2015. 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/