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
   202012    -1.14
   202101    -1.03
   202101    -1.03
   202102    -0.89
   202103    -0.67
   202104    -0.50
   202105    -0.37
   202106    -0.32
   202107    -0.34
   202108    -0.45
   202109    -0.59