File name

STJ1574_13.gag

STJ            rain gauge network (in this case, STJ denotes St. John’s River Water Management District) 
1574           rain gauge ID 
13             Year 2013  
gag            Product ID (reformated gauge tip data) 

File header

STJ1574 St_Augustine_Shores -81 18 49.1 29 47 58.5

GAG STJ1574           same as in file name 
St_Augustine_Shores   gauge location
-81 18 49.1           gauge longitude (81o18' 49.1") 
 29 47 58.5           gauge latitude  (29o47' 58.5") 

Data format

......................................
2013 01 07 007 23 00 00 0.02
2013 01 08 008 16 26 19 0.01
2013 01 08 008 20 31 38 0.01
2013 01 08 008 20 35 14 0.01
2013 01 08 008 20 42 15 0.01
2013 01 08 008 20 52 11 0.01
2013 01 08 008 20 52 14 0.01
2013 01 08 008 20 56 12 0.01
2013 01 09 009 20 19 14 0.01
2013 01 12 012 17 32 12 0.01
2013 01 17 017 22 28 17 0.01
2013 01 27 027 18 19 43 0.01
2013 01 27 027 18 19 45 0.01
......................................

There are 8 data fields. 
1) year 
2) month
3) day of month
4) Julian Day of year
5) hour in UTC 
6) minute 
7) second 
8) rain [inch]  (eg. 1 tip = 0.01 inch)