Friday began on a mild note with readings in the low 50s, but the mercury tumbled into the low 40s during the afternoon as north-northeast winds gusting near 40 mph brought a blustery chill accompanied by scattered lake-effect rain showers, a product of Lake Michigan water temperatures still in the 50s. Saturday morning will dawn chilly with lows in the low and mid-30s along with some areas of frost and freeze. Even though this weekend's high temperatures are expected to climb only to the low or mid-50s — making this the city's coolest weekend since mid-May when highs reached 47 and 55 on May 14-15, respectively — these readings will still be above the normal high of 50 degrees. The mild trend is expected to continue next week with afternoon highs in the low 60s by Thursday and Friday.