CFSv2 Seasonal SSTs (clim19912020)
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
   202306     0.77
   202307     0.97
   202308     1.20
   202309     1.51
   202310     1.77
   202311     1.82
   202312     1.73
   202401     1.56
   202402     1.42
   202403     1.32