>I just took a quick look at NINO3.4 SST Anomalies, and for the week centered on Wednesday May 12th, they’ve dropped into negative numbers: -0.075 deg C.
http://i44.tinypic.com/x10s9y.png
NINO3.4 SST Anomalies – Week Of May 12, 2010
SOURCE
OI.v2 SST anomaly data is available through the NOAA NOMADS website:
http://nomad3.ncep.noaa.gov/cgi-bin/pdisp_sst.sh?lite=