BALTIMORE (WJZ) — A heat advisory went into effect at noon today for a large portion of the state.

The heat advisory has been issued for Anne Arundel, Baltimore, Calvert, Howard, Montgomery, Charles, Prince George’s, Harford, and St. Mary’s Counties, along with Baltimore City, from noon until 8 p.m.

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“It is the combination of the heat and the humidity that could create dangerous conditions for anyone susceptible to heat-related problems,” WJZ Meteorologist Tim Williams says. “So if you’re going to be outside, stay hydrated, stay in the shade, definitely do not exert yourself if at all possible and just try not to overdo it.”

Tim says these are the highest temperatures we’ve seen so far this summer. The heat index was already in the triple digits at noon.

The current heat record for the day is 99 degrees, set in 1966.

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There is also a possibility of thunderstorms in the early evening, between 6 p.m. and 7:30 p.m.

“This atmosphere is just going to need to flex,” says WJZ’s Marty Bass. “And when it does there’s going to be some cause and effect.”

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There could be damaging winds, and hail is even possible.

Baltimore City Health Commissioner Dr. Leana Wen has issued a Code Red heat advisory for the area. She says the heat could become dangerous.

“Heat is a silent killer and a public health threat, particularly for the young, the elderly and those in our city who are the most vulnerable,” said  Wen.

“With extreme heat expected, it is important for all residents to protect against hyperthermia and dehydration. Please be cautious and remember to stay cool and hydrated.”

The Health Commissioner can declare a Code Red alert during periods of heat that are severe enough to present a substantial threat to life or health of vulnerable Baltimore citizens including the young and elderly.

For a list of city cooling centers, CLICK HERE.

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