3       row variables and mean/spread/prob info
U      33   100  M5  1000 850 700 500 250 
V      34   100  M5  1000 850 700 500 250
W      39   100  M5  1000 850 700 500 250
  1      special derived variables, each  of which, needs code to process specially
DTRA  501   100  M5  1000 850 700 500 250