Bug not so buggy MESONET ridprefix must be case-sensitive

[acidhorse1972]

// if you try https://mesonet-nexrad.agron.iastate.edu/level2/raw/khtx/
// it will return a 404 NOT FOUND error
// MESONET is case-sensitive so you mustn't use lower-case letters in the function above
// This is how it should be https://mesonet-nexrad.agron.iastate.edu/level2/raw/KHTX/