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
   201909     0.06
   201910     0.27
   201911     0.40
   201912     0.30
   202001     0.20
   202002     0.21
   202003     0.25
   202004     0.28
   202005     0.22
   202006     0.04