The cities of Medford and Ashland will open temporary cooling shelters as Jackson and Josephine counties and other areas of Southern Oregon face a heat advisory lasting until 8 a.m. Saturday.

Daytime temperatures are expected to climb into the high 90s and may reach as high as 106 Thursday in Medford, according to the advisory and the latest forecast for Medford. Overnight temperatures will fall between the high 50s and high 60s, according to the advisory issued Wednesday.

“Hot temperatures may cause heat illness,” the advisory said.

In addition: “Certain medications may make you more vulnerable to heat illness,” the advisory said. “(C)heck with your doctor or pharmacist for details.”

The NWS advisory recommends that people drink lots of fluids, use air conditioning, avoid the sun and make sure relatives and neighbors are OK.

People who head outside should wear clothes that are lightweight and loose-fitting, the advisory said.

“Try to limit strenuous activities to early morning or evening,” the advisory said. “Take action when you see symptoms of heat exhaustion and heat stroke.”

According to the federal Centers for Disease Control and Prevention, people suffering from heat-stroke can experience body temperatures of at least 103. Other symptoms include a hard, rapid pulse, “hot, red, dry or damp skin,” headache, nausea, dizziness, confusion and fainting, the CDC website says.

Heat exhaustion, the CDC says, can entail “heavy sweating,” as well as “cold, pale and clammy skin,” a pulse that is rapid but weak, muscle cramps and vomiting, according to the agency website.

NWS also recommends that people who work outdoors take “frequent rest breaks in shaded or air-conditioned environments.”

“Anyone overcome by heat should be moved to a cool and shaded location,” the advisory said. “Heat stroke is an emergency! Call 911.”

Medford has opened a shelter at 324 W. 6th St., operated by ACCESS volunteers. Hours are noon to 8 p.m. Thursday and Friday, city officials announced.

The shelter will provide water, restrooms, snacks and a cooling area and water for pets. People can come and go. Text MED4SHELTERS to 888777 to receive the latest information on shelter activations in Medford.

The city of Ashland will open a cooling center from noon to 7 p.m. Thursday and Friday at 2200 Ashland St.

“Space is limited,” a city release said. “This is a low-barrier, no-frills, cooling center — a safe and clean space with access to cool water and restrooms. The center is staffed at all times by volunteers.”

See ashlandoregon.gov or text 97520SHELTER to 888777 to be notified about upcoming shelter activations.