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
   202409    -0.44
   202410    -0.72
   202411    -0.97
   202412    -0.95
   202501    -0.84
   202502    -0.56
   202503    -0.24
   202504     0.03
   202505     0.18
   202506     0.22