CFSv2 Seasonal SSTs (clim19822010)
first  rec: avg(lastbs-1, lastobs, CFSv2 month 1)
second rec: avg(lastbs, cfs month 1, CFSv2 month 2)
last   rec: CFSv2 month 9
other  rec: CFSv2 3-mo average
 TrgSeason    SST34
   201705     0.54
   201706     0.59
   201707     0.57
   201708     0.47
   201709     0.39
   201710     0.37
   201711     0.27
   201712     0.07
   201801    -0.03
   201802     0.01