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
   201806     0.12
   201807     0.38
   201808     0.64
   201809     0.99
   201810     1.29
   201811     1.36
   201812     1.18
   201901     0.95
   201902     0.84
   201903     0.90