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
   202404     0.80
   202405     0.28
   202406    -0.26
   202407    -0.70
   202408    -1.03
   202409    -1.32
   202410    -1.58
   202411    -1.74
   202412    -1.72
   202501    -1.59