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
   201809     0.42
   201810     0.72
   201811     1.02
   201812     1.08
   201901     1.05
   201902     0.99
   201903     1.00
   201904     0.98
   201905     0.90
   201906     0.74