The National Weather Service of Honolulu has issued a red flag warning for the leeward side of all Hawaiian isles, effective until 6 p.m. Thursday.

A red flag warning means that critical fire weather conditions are either occurring now or will shortly, according to NWS, due to a combination of strong winds, low relative humidity, and warm temperatures.

The advisory areas range from the leeward side of Kauai to Oahu’s Waianae coast and mountains and north and south shores; the leeward side of Molokai; the central valley and west side of Maui; Haleakala; and Kona and Kohala on Hawaii island.

“Although windward areas did recently receive some rainfall, fuels remain dry in leeward areas,” said NWS in the advisory. “Combined with gusty trade winds and low relative [humidity], critical fire weather conditions are expected over leeward areas this afternoon, and again on Thursday afternoon.”

Weather officials said trades of up to 20 mph, with locally higher gusts, are expected, while humidity is expected in the 40% to 45% range through afternoon hours.

Any fires that develop will likely spread rapidly, officials said. Outdoor burning is not recommended.