(By Ely Portillo and Steve Lyttle, elyportillo@charlotteobserver.com; slyttle@charlotteobserver.com) Sunshine and above-freezing temperatures are melting snow and ice across the Charlotte metro region again today, after residents dealt with yet another morning of treacherous roads and sidewalks.But forecasters are nervous about a weak storm system that could bring some freezing rain early Tuesday to the area -- and an even stronger system that could threaten the region with snow, sleet and freezing rain Friday and Saturday.