slp        precip at 40N Jan every 10 deg
   1013.77      4.31
   1012.98      4.65
   1014.87      3.81
   1014.78      3.73
   1017.59      2.93
   1021.42      0.00
   1026.60      0.00
   1027.29      2.33
   1031.14      0.00
   1032.71      0.00
   1030.42      0.00
   1028.49      0.00
   1025.68      0.00
   1021.96      0.00
   1014.97      3.53
   1011.01      2.72
   1007.15      4.11
   1003.46      4.22
   1002.03      6.53
   1004.51      6.41
   1009.00      7.66
   1012.73      5.39
   1015.28      4.15
   1016.24      3.67
   1022.27      2.01
   1026.24      0.00
   1024.14      0.00
   1020.36      2.05
   1015.69      4.64
   1011.84     10.01
   1010.73      4.70
   1011.84      3.95
   1013.71      3.74
   1015.50      3.83
   1014.91      2.47
   1013.17      7.49