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
   202003     0.51
   202004     0.44
   202004     0.44
   202005     0.15
   202006    -0.25
   202007    -0.55
   202008    -0.77
   202009    -0.96
   202010    -1.15
   202011    -1.33
   202012    -1.49