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FCAC ( CACOF ) FORO DEL CLIMA DE AMERICA CENTRAL. Meteorological drought forecasting Inter-COF collaboration with Central America. Cedric J. VAN MEERBEECK 1 , Simon J. Mason 2 , Berny Fallas 3 and Patricia Ramirez 4
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FCAC (CACOF) FORO DEL CLIMA DE AMERICA CENTRAL Meteorological drought forecastingInter-COF collaboration with Central America Cedric J. VAN MEERBEECK1, Simon J. Mason2, Berny Fallas3and Patricia Ramirez4 1The Caribbean Institute for Meteorology and Hydrology (CIMH), 2International Research Institute for Climate and Society (IRI), 3Instituto Costarricensede Electricidad (ICE), 4Comité Regional de RecursosHidráulicos (CRRH) CariCOF Seasonal Forecast Training, May 26-27, Kingston, Jamaica
Regional Climate Outlook ForumsCariCOF- FCAC CariCOF FCAC
Drought Early Warning (DEW) Depicting the 2009-2010 Caribbean Drought Monitoring: Caribbean (and Central American!!) SPI and Deciles(Caribbean Drought and Precipitation Monitoring Network)Prediction: Caribbean and Central American seasonal precipitation outlook (FCAC and CariCOF)
Drought Early Warning (DEW) Where are we now? But: Even if reliable, how easily could we use a singular forecast of 25% … 35% … 40% of below-normal rainfall? So we produce seasonal forecasts for the Caribbean and Central America… CariCOF Dec2013-Jan-Feb 2014 & Mar-Apr-May 2014 FCAC Dec2013-Jan-Feb-Mar 2014
Drought Early Warning (DEW) Where do we want to go? But:Even if reliable, how easily could we use a singular forecast of 25% … 35% … 40% of below-normal rainfall? • What kind of drought forecasts best inform DEW? • Reliable = forecast probabilities correspond well with observed frequencies • Timely • Understandable language • Salient = forecast must relate to an outcome of direct interest to the user • Sharp = assigned probabilities are high enough for effective sectoral resources allocation • Cost-effective and sustainable = requiring guaranteed continuity of operations in the face of frequent understaffing and limited funding
Drought forecasting – how will it work? HOW MUCH RAINFALL WE NORMALLY EXPECT
Drought forecasting – how will it work? HOW MUCH RAINFALL WE EXPECTED IN JFM
Why add in persistence in seasonal forecasts TRADITIONAL SEASONAL RAINFALL OUTLOOK
Why add in persistence in seasonal forecasts HOW MUCH RAIN FELL SO FAR?
Why add in persistence in seasonal forecasts SAME SEASONAL RAINFALL FORECASTbut adding in observed rainfall surplus/deficit
Why add in persistence in seasonal forecasts THIS IS WHAT REALLY HAPPENED!!
SPI thresholds – drought and excessive precip. SPI = rainfall totals over a period expressed in units of standard deviations around the historical mean as determined using a gamma distribution. Caribbean Drought and Precipitation Monitoring Network adopted the following thresholds: Table SPI classification used from January 2011
6-month SPI demo for OND2009 – JFM2010 CDPMN Monitor – old drought categories
6-month SPI demo for OND2009 – JFM2010 Initial results – Drought probabilities
Drought risk forecasting – how could it look like? WHERE IS DROUGHT RISK IMMINENT?HOW BAD WILL IT GET 3 MONTHS FROM NOW?
6-month SPI demo for OND2009 – JFM2010 Region-wide verification BARBADOS GRENADA
Drought outlook for the end of August 20146-month SPI outlook
SPI outlook MAMJJA – what’s the probability for impactful drought? • In the wet season, sufficient rain falls over the territories to not cause drought impacts, even when rainfall is a bit lower than usual. • Only severely dry conditions (or worse) would cause significant impacts to our economic sectors, in particular agriculture and water resource management. • So we ask: • for the hurricane season 2014, what are the chances for impactful drought across the Caribbean? • Is there any area where drought risk is imminent? • Is there any concern beyond the wet/hurricane season?
SPI outlook MAMJJA1. what’s the probability for impactful drought? Except for coastal French Guiana, which is actually entering a dry season in August, we expect impactful drought isunlikely.
SPI outlook MAMJJA2. any area with imminent drought risk? Drought is imminent over French Guiana.
SPI outlook MAMJJA3. any concern beyond the wet/hurricane season? • El Niño is associated with a drier wet season. • If El Niño manifests, less water will be stored during the wet season. • By consequence, less water would be available for use in the dry season, which is our tourist season. CONSERVE WATER!!Especially in the Eastern and Southern Caribbean
SPI outlooks – what lies ahead? • Development, Tailoring, Operationalisation, Improvement and Streamlining of the SPI outlook methodology by CariCOF and FCAC. This includes: • technical capacity building through training workshops: Jamaica, 26-27 May + Costa Rica, 2-6 June • enhanced stakeholder participation; • targeted climate products and services development. • Questions we, Meteorologists and Climatologists, ask you the Users: • What is the most usable output visualisation of the SPI outlook to you? Maps? Tables? … • Which time scale and time lead is most usable to you? • Are you more interested in probabilities or odds/relative odds?