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
   201812     0.69
   201901     0.67
   201902     0.72
   201903     0.81
   201904     0.86
   201905     0.87
   201906     0.87
   201907     0.87
   201908     0.79
   201909     0.64