...A Heat Advisory remains in effect for the entire Four State Region through 7 PM CDT Tuesday... ...HEAT ADVISORY NOW IN EFFECT UNTIL 7 PM CDT WEDNESDAY... * EVENT...An upper level ridge will remain in place across the Southern Plains through Wednesday, resulting in afternoon temperatures again climbing into the mid 90s to near 100 degrees. Southerly winds will maintain the high humidity through Tuesday, with resultant heat indices ranging from 105 to 110 degrees. Limited relief from the heat is expected tonight, with low temperatures only falling briefly into the mid and upper 70s. * TIMING...Through 7 pm CDT Wednesday. * IMPACT...High heat index readings will increase the risk of heat-related illnesses.