The combined data set of polar mesospheric clouds (PMCs) from multiple SBUV instruments, which now extends for 38 years, has been shown to be very effective for evaluating long-term trends of ice water content, temperature, and water vapor in the mesosphere. These studies have focused on the latitude range where PMCs are most commonly observed (>50° in both hemispheres). Increased mesospheric water vapor (resulting from increasing methane) and decreased mesospheric temperature (caused by CO2 cooling) are also predicted to expand the PMC existence region to lower latitudes. However, this region (e.g. 40°-50° latitude) is very challenging for nadir-viewing PMC detection due to the combination of higher background albedo, weaker PMC signal, and greater stratospheric ozone variability. Current SBUV results in this region are quite uncertain, and difficult to validate. The Ozone Mapping and Profiler Suite (OMPS), flying on the Suomi NPP satellite, includes a Nadir Profiler (NP) instrument that is very similar to SBUV. OMPS also includes a Limb Profiler (LP) instrument that measures limb scattered radiation looking backwards along the S-NPP orbit track. LP thus collects “common volume” profile measurements with 1 km sampling approximately 7 minutes after NP observations along the entire S-NPP orbit. The LP data provide a robust indicator of PMC existence and brightness that can be used to evaluate NP performance. We will present results from 5 years of S-NPP observations.