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
   202408    -0.17
   202409    -0.58
   202410    -0.94
   202411    -1.12
   202412    -1.09
   202501    -0.93
   202502    -0.61
   202503    -0.21
   202504     0.14
   202505     0.37