The National Weather Service in Medford Friday extended its Excessive Heat Warning for Jackson County as local meteorologists anticipate triple-digit temperatures continuing into early next week — and possibly matching or surpassing an all-time temperature record.

The new advisory warns of “dangerously hot conditions” through at least 9 p.m. Tuesday in Jackson County and portions of Josephine, Curry, and Siskiyou counties.

The updated advisory states that the Weather Service’s Medford airport weather station has a 40% chance of tying or exceeding its all-time temperature record of 115 degrees Fahrenheit on Saturday.

The Weather Service’s Excessive Heat Watch began with triple-digits July 4, and the current forecast shows highs at or in excess of 100 degrees potentially lasting through Thursday, July 11.

Officials in Medford have worked with ACCESS to open a cooling shelter until 8 p.m. Friday and from noon to 8 p.m. Saturday and Sunday, July 6 and 7, at the former Kelly Shelter, 324 W. Sixth St. in Medford. Ashland has activated a cooling center until 7 p.m. Friday and from noon to 7 p.m. Saturday and Sunday, July 6 and 7, at 2200 Ashland St. The cooling center may extend to July 8 and 9, depending on the heat wave and volunteer availability to staff the shelter, city officials said this past week.

For info on Medford shelter openings and updates, text MEDF4SHELTERS to 888777. To be updated on Ashland shelter activations, see ashlandoregon.gov or text 97520SHELTER to 888777.

The apex of the heat wave will be Saturday, when the forecast calls for a high of 113 degrees, according to the NWS website on Friday. It will shatter the previous record of 104 degrees, set on July 6, 1922, according to almanac data provided by Dan Weygand, lead meteorologist at the local Weather Service.

During an Excessive Heat Warning, the Weather Service advises that people take precautions to avoid heat-related illness, such as staying hydrated and staying indoors in air conditioned spaces when possible.

The heat would be a strong start for breaking Medford’s record for the most 100-degree days in July — 13 — set in 2014.