A Review of the 2009-10 El Nino Winter

Sam Lashley
Senior Meteorologist
NWS Northern Indiana

A strong El Nino episode was ongoing during the 2009-10 Winter Season. The development of El Nino conditions were forecast well in advance by the National Weather Service (NWS) Climate Prediction Center (CPC).  The CPC began issuing discussions related to a possible El Nino event during the early summer of 2009. The first “El Nino Watch” was issued in June and the first “El Nino Advisory” was issued in July along with expected impacts during the winter across the United States. The Winter Outlook issued by CPC in the fall of 2009 was heavily weighted toward typical El Nino impacts across the United States.  

This presentation will look back at the winter months of 2009-2010 to see how conditions across the NWS Northern Indiana Office forecast area (Northern Indiana, Southwest Lower Michigan and Northwest Ohio) compared to normal and to conditions typically expected during El Nino events as forecast by CPC. The presentation will focus on long range outlooks issued prior to the winter season, the large scale atmospheric pattern and El Nino strength during the winter months, and actual weather conditions that occurred across our local area.