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
   201708    -0.17
   201709    -0.61
   201710    -0.96
   201711    -1.23
   201712    -1.47
   201801    -1.55
   201802    -1.37
   201803    -1.00
   201804    -0.63
   201805    -0.35