Many moons ago, the IEM started providing a website with the National Weather Service NEXRAD Level II data. The address to this website was the same hostname as the main IEM website. The bandwidth for this service would over-whelm the website, so it was moved to a new URL back in May 2012.
I added an automatic redirect for folks using the old address to the new address. This redirect creates needless load on the servers and is not efficient. It also creates confusion, as on Thursday 3 April, when the IEM webfarm grinds to a halt, but the nexrad service chugs along happily. Folks using the redirect think the actual level II website is down or very slow, when it is actually fine.
So on Monday morning (7 April), I am removing this redirect and folks will need to manually update their software to use the new address. Summarizing:
OLD: http://mesonet.agron.iastate.edu/data/nexrd2/raw/ NEW: http://mesonet-nexrad.agron.iastate.edu/level2/raw/
The software change is typically modifying the polling address. Please let me know of any questions.