QuikScat has SIGNIFICANT limitations in detecting small circulation centers. It has missed a few TDs in the Gulf over the past few years when Recon. itself was able to fix a well-defined LLC (can't remember which one, but as I recall, Derek was "open waving" that one as well).
Remember Hurricane Iris back a few years ago? Tiny hurricane with 145 mph in the Caribbean. At the time, QuikScat showed NO CLOSED CIRCULATION, but easterly winds south of the CAT 4 hurricane. Was Iris an open wave at the time? No, no, no.
http://storm.aoml.noaa.gov/Hwind/Public ... _paper.pdf
Quoting page 10: "The QuikSCAT observations that were
received in H*Wind at 1127 UTC for Hurricane Iris on 8 October showed an easterly flow over the entire storm, and did not acknowledge any sign of a closed circulation at the surface (FIGURE 3A)."
As you can see in the figure on page 10 of that report, the study had to apply an algorithm to correct QuikScat's wind barbs south of Iris that were 180 degrees from the direction they should have been.