How to save data in a formatted text file

I have 2 vectors and an array that I need to write into a text file in a particular format (to be read by another program). The first line of the text file is the header info, that contains (num_alts, starting alt, alt div, num lats, starting lat, lat division):

num_alts = 5;
num_lats = 1:1:3;
header = [5, 60.000000, 100.0000000, 3, 45.0000, 2.00000];

The next part of the text file are integers from 0 to the number of alts: alt_int=0:1:num_alts;

Next, for each num_lat (from header file), there is a vector of data (from an array) that needs to be printed num_lat1, data1, new row, num_lat2, data2, new row, num_lat3, data3. There may be multiple rows of data for each num_lat. There data* is a column in an array called 'ne_profiles' Here is an example of the output I require:

5 60.000000 100.0000000 3 45.0000 2.00000 0.0 1 2 3 4 5 1 45.0 1.00000000e+000 4.88660000e+010 6.43080000e+011 8.23960000e+010 .... 1.02960000e+10 2 47.0 1.00000000e+000 3.88660000e+010 5.43080000e+011 6.23960000e+010 .... 2.02960000e+10 3 49.0 1.00000000e+000 5.88660000e+010 4.43080000e+011 5.23960000e+010 .... 3.02960000e+10

A txt file of a larger formatted data set is also attached (test.txt).

I was thinking I could create a new variable and format it from previous variable, but then any unused cells of the array receive a value of 0, which messes up the formatting for the text file. There must be an easier way to save the text file with multiple variables(a vector for each numlat*/data*), specifying how it should be written (e.g. new line after each latitudes data)

   %Format PRF file as a variable
    %prf_file(1,1) = max(max(altitudes));%max altitude
    prf_file(1,1) = length(altitudes); %number of alts 1000
    prf_file(1,2) = min(min(altitudes));%starting alt 60 km
    prf_file(1,3) = altitudes(2,1) - altitudes(1,1); %alt div 1 km
    prf_file(1,4) = length(Latitude);% num lats,  
    prf_file(1,5) = min(min(Latitude));%starting lat,
    prf_file(1,6) = Latitude(1,2) - Latitude(1,1);%lat division
    prf_file(1,7:1:prf_file(1,1)+7) = 0:1:prf_file(1,1);
  for i = 1:prf_file(1,4)%length(Latitude)
      %j=i+1;%row index
      prf_file(i+1,1) = i;
      prf_file(i+1,2:length(altitudes)+1) = ne_profiles(1:length(altitudes),i);
  end
    save('mytest_PRF.txt', 'prf_file', '-ASCII','-append');

Any suggestions would be appreciated.

Best regards,

Alex