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
   202104    -0.50
   202105    -0.38
   202105    -0.38
   202106    -0.26
   202107    -0.20
   202108    -0.23
   202109    -0.29
   202110    -0.42
   202111    -0.51
   202112    -0.54
   202201    -0.52