Long-Lead Seasonal Temperature and Precipitation Prediction Using Tropical Pacific SST Consolidation Forecasts

Abstract

Objective seasonal forecasts of temperature and precipitation for the conterminous United States are produced using tropical Pacific sea surface temperature forecasts for the Niño-3.4 region in conjunction with composites of observed temperature and precipitation keyed to phases of the ENSO cycle. The objective seasonal forecasts are validated against observations for the period February?March?April (FMA) 1995 to September?October?November (SON) 2002, and compared to NOAA's Official Seasonal Forecasts issued by the Climate Prediction Center (CPC) for the same period. The objective forecasts are shown to produce skill that is comparable to (and even exceeding) that achieved by the Official Seasonal Forecasts at all leads out to 12.5 months. The forecasts are divided into high-frequency (HF) and trend-adjusted (TA) components in order to show that seasonal forecasters could achieve higher skill in both temperature and precipitation forecasts by taking full advantage of trend information, especially at longer leads. The objective forecasts are fully automated and available each month as a tool for use in preparation of the Official Seasonal Forecasts. (The latest objective forecasts are available on the CPC homepage at http://www.cpc.ncep.noaa.gov/products/precip/CWlink/ENSO/total.html.)