Bone-chilling fog hung low in the Rogue Valley Thursday, and weather prognosticators say the murky layer likely will stick around through the middle of next week.
The National Weather Service issued a dense fog advisory that remains in effect until 10 a.m. today.
"We don't have it breaking up totally," meteorologist Chuck Glaser said. "There'll be some times we might get a little clearing. There will be some pockets where it's stronger than others."
Visibility remained at one-quarter mile for most of the Rogue Valley until noon Thursday, but increased to one mile of visibility by 2 p.m. and about 211/2; miles by about 3 p.m.
Visibility is expected to decrease again during the cooler nighttime hours.
"A quarter (mile) is the lowest it's been all night long," Glaser said.
Meteorologists advise drivers to be cautious while driving on the roads because of the nip in the air, saying the fog may cause ice to form on some of the roads, especially on bridges and overpasses.
Medford airport officials said two arriving flights were canceled on Christmas Day because of the fog. There were two additional cancellations Thursday morning, but airport officials reported a majority of flights have been arriving as scheduled.
"We're looking pretty good," said airport director Bern Case, adding crews performing cloud seeding operations Thursday morning in an attempt to thin the fog further. Continued seeding operations may result in light snow in the vicinity of the airport, potentially adding to the slickness on nearby roads.
The cold, damp haze is hanging on because of a strong temperature inversion hovering over the area. It has prompted weather officials to issue an air stagnation advisory through New Year's Day.
"Possibly it'll go beyond that," Glaser said.
Temperature highs are expected to remain in the 40s for the rest of the week. Nighttime lows are expected to drop into the high 20s.
Reach reporter Ryan Pfeil at 541-776-4468 or by email at firstname.lastname@example.org.