It was a steamy Independence Day over much of the eastern half of the nation, especially in the Ohio Valley and Northeast, where the temperatures surged into the 90s with high humidity. Record highs fell in New York, Georgia, and Maine. More heat is ahead today (Thursday), as the heat index will lift into the triple digits along the Mississippi and Ohio Rivers, and approach 100 into New England. The mercury will surge into the 90s. Heat related illnesses such as heat exhaustion and heat stroke will be possible. People most vulnerable include those who are spending lots of time outdoors, those who do not have air conditioning, young children, the elderly, and those with chronic ailments. Recognize the signs and symptoms of heat illness. Early symptoms include things such as headache, thirst, and muscle cramps. Serious symptoms include weakness, skin that is cool to the touch, fast but weak pulse, nausea, and fainting. Severe symptoms include hot and red dry skin, fast and strong pulse, sweating that has stopped, and unconsciousness. Untreated heat illness can lead to fatal heat stroke. For WeatherNation: Meteorologist Mace Michaels