Some parts of north Alabama saw their first 100-degree temperature readings Tuesday, with a persistent swell of heat and humidity conspiring to inch heart indices near a dangerous 110 degrees through the remainder of this week.

Even as the mercury hits triple digits in neighboring counties, Cullman will likely see daytime high temperatures that top out in the mid-90s from now until Saturday. That’s hardly a reprieve, though: The Huntsville office of the National Weather Service has extended the ongoing heat advisory for its entire north Alabama coverage area, including Cullman County, until 7 p.m. on Friday.

NWS advises safety measures that most won’t have to hear twice: Staying in places where it’s comfortably cool during the hottest part of the day. “Hot temperatures and high humidity may cause heat illnesses to occur,” NWS warns, urging residents to “drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors.”

Those measures won’t be available to everyone, though — especially those whose day jobs keep them outdoors. If your work puts you in close contact with the elements this week, NWS advises extra precautions including frequent breaks in shaded and air conditioned areas, wearing light and loose-fitting clothing, and knowing ahead of time how to spot the signs of heat-related illnesses.

Key to protecting yourself and loved ones when the temperature surges is learning the difference between signs of heat exhaustion and the more serious, emergent signs of heat stroke.

Faintness, dizziness, excessive sweating, clammy skin, nausea, muscle cramps, and a rapid or weak pulse all can signal heat exhaustion. In most cases, finding a cooler, air conditioned space and drinking plenty of water can aid in helping those signs subside, along with taking a cool shower or applying cold compresses.

Heat stroke, on the other hand, requires rapid attention. If you or anyone nearby experiences signs of heat stroke, call 911 and take immediate action to cool off. Signs of heat stroke can include a lack of sweat, throbbing headache, a strong rapid pulse, skin that’s red, hot, and dry, and a body temperature in excess of 103 degrees. In some cases, a person suffering from heat stroke also may lose consciousness.

Though forecasts through Friday call for a moderate afternoon chance of rain each day, no substantial rainfall is on meteorologists’ horizon until Saturday at the earliest, when the chance of rain rises to 70 percent. Thanks to a seasonably wet spring and recent rains, Cullman County remains free from any current drought advisories — though portions of Alabama to the north and south have been placed under the U.S. Drought Monitor’s “Abnormally Dry” advisory status, the agency’s lowest-grade drought threat.

Children, pets, and the elderly are especially at risk in extreme heat. Never leave pets or people in unattended vehicles on a hot day, NWS cautions, and check in on older relatives and acquaintances to ensure they’re remaining in air conditioned areas and have access to water and a phone.