The National Weather Service in Mount Holly has issued a heat advisory, which is in effect from noon Tuesday until 8 p.m. Wednesday.

Maximum heat index values are forecast to be around 100 in the valleys on Tuesday afternoon and Wednesday afternoon.

Maximum temperatures in the valleys are expected to be in the lower 90s on Tuesday and Wednesday. Lows on Tuesday night are anticipated to be in the lower 70s.

The excessive heat will create a health risk, especially for the elderly and for those with pre-existing health issues.

Here is the latest forecast:

Today: Patchy fog before 9am. Otherwise, mostly sunny, with a high near 87. Calm wind becoming west around 6 mph in the afternoon.

Tonight: Patchy fog after 2am. Otherwise, partly cloudy, with a low around 71. West wind around 5 mph becoming calm after midnight.

Tuesday: Patchy fog before 8am. Otherwise, mostly sunny, with a high near 92. Calm wind becoming west 5 to 8 mph in the morning.

Tuesday Night: Mostly clear, with a low around 72. Southwest wind around 6 mph becoming calm in the evening.

Wednesday: Sunny, with a high near 91. Light west wind becoming southwest 5 to 10 mph in the morning.

Wednesday Night: A slight chance of showers and thunderstorms. Partly cloudy, with a low around 71. Chance of precipitation is 20%.

Thursday: A chance of showers and thunderstorms after 11am. Mostly sunny, with a high near 85. Chance of precipitation is 30%.

Thursday Night: A chance of showers. Mostly cloudy, with a low around 63. Chance of precipitation is 30%.

Friday: A chance of showers. Partly sunny, with a high near 79. Chance of precipitation is 30%.

Friday Night: A chance of showers. Mostly cloudy, with a low around 63. Chance of precipitation is 30%.

Saturday: A chance of showers. Partly sunny, with a high near 76. Chance of precipitation is 30%.

Saturday Night: Mostly cloudy, with a low around 64.

Sunday: A chance of showers and thunderstorms. Partly sunny, with a high near 81. Chance of precipitation is 30%.