MEM Local Controller described a loss of separation event during simultaneous approach procedures to Runways 36L/R and Runway 9; claiming the weather conditions were unsuitable for the operation.

Narrative

MEM was running ILS staggered approaches to Runways 36L and 36R and ILS approaches to Runway 9. The weather was low ceilings and poor visibility. The M03 Final Controller for Runway 36L had given me several aircraft that were compressing hard on the preceding Runway 36R arrival. So I had to watch the compression issues; get the aircraft arriving Runway 36L in sight as well as the aircraft arriving Runway 9; as well as get departures out off [of] Runway 9 as soon as I could see the arriving aircraft on Runway 36R. There had already been breakouts due to aircraft being too high for the approach or compression on Runway 36L. I mentioned to the supervisor that we should suspend Runway 9 arrivals if we were going to continue to have compression issues with the Runway 36L and 36R arrivals because I didn't have anywhere to go with missed approaches off of Runway 36L. I broke our MD88 off of Runway 36L because of compression issues. I issued him a turn to heading 250 and an altitude of 2;000. He initially turned but then I noticed that it appeared that he had stopped his turn on a 310 or so heading and was still heading towards the Runway 9 final. I told him to turn NOW to a 230 heading and broke a CL65 off of the Runway 9 final to ensure separation. When the ceilings or visibility are low; DO NOT run two CONVERGING runways. M03 had simultaneous parallel approaches; we need to use them.