New York City experiences record-breaking heatwave

Cold air doesn't clash with hot air as dramatically, so the jet stream calms down and drifts further up towards the pole. As the jet stream buckles and slows, this can allow high-pressure systems to move into an area. As we've seen, these high-pressure systems can cause a heatwave.

The hottest it has ever reached in Central Park was 106 degrees, on July 9, 1936. Just by reaching 97 degrees in the afternoon, Mr. Ramsey said, Central Park had already surpassed a record for the date that had stood since 1888.

If the temperature in Central Park were to climb to 100 degrees, it would be the first time it would hit triple digits since July 18, 2012.