PIEDMONT TRIAD, N.C. (WGHP) — A Dense Fog Advisory is in effect until 10 a.m. Visibility is expected to drop to ¼ mile or less for several hours during the morning commute.  Please use caution when traveling across the Piedmont. Dense fog affecting Triad drivers on Wednesday morning Cloudy skies are ahead for today, with unseasonably warm high temperatures, in the mid-60s.  A cold front is going to cross the mountains this evening, bringing a line of showers to the Piedmont around the dinner hour.  The front itself won't cross the Piedmont until later tonight, but it will be bringing chillier air to the end of the week.  We're expecting partly to mostly cloudy skies Thursday and Friday, with highs in the upper-40's to lower-50s. A second cold front barrels through the Carolinas late Friday, bringing cold, Arctic air to the weekend forecast.  Highs will drop to the lower-40s Saturday under partly cloudy skies.  Sunday and Monday, lows will be in the lower-20s to upper-teens, and highs will only make it to the upper-30s! The forecast becomes a little better Tuesday, which is Christmas Eve.  We will have partly cloudy skies with highs in the mid-40s.