Network Hash Rate 19,722.259 GH/s
I think you are off by 1000. There is no way the Litecoin hashrate is 19TH/s with scrypt.
It's clearly almost 20 GH/s, but that is still almost double what it was a week ago. Apparently all of the new alt-coins can't put a dent into LTC mining or those rumored FPGA miners have entered the "minestream."