The National Weather Service's Honolulu office has a new tool to alert government officials and the public when weather conditions could spawn wildfires.

The Fire Weather Watch and Red Flag Warning Program will combine a drought index number with sustained wind speed and relative humidity to determine when to post a fire warning.

On days when the relative humidity is 45 percent or less, sustained winds are 20 mph or greater, and the drought index number is 600 or more, a fire watch or warning will be posted on the National Weather Service Web site, and public officials and the media will be alerted.

The program will operate much in the same way as high surf or flash flood watches and warnings are now issued, said Ray Tanabe, warning coordination meteorologist with the Honolulu National Weather Service office.

"We expect there may be four or five days during the summer months when we need to post fire watches or warnings," Tanabe said.

Last summer, the large Waialua brushfire on O'ahu and Olowalu fire on Maui occurred within two nearly one-week runs of "red flag" days, Tanabe said. Last year was a bit unusual in that there were about 20 days on which a fire watch or red-flag warning could have been issued, he said.

The issuance of a red-flag warning does not predict or guarantee new fires will occur, but warns that fuel and weather conditions are conducive for new ignitions and control problems with existing fires, weather service officials said.

Capt. Terry Seelig, spokesman for the Honolulu Fire Department, said the new fire watch and warning advisories will enable the Fire Department to urge greater public vigilance in preventing fires and to issue reminders to the public to report a fire or suspicious activity as quickly as possible during fire watches or red-flag warnings.

"It gives us another opportunity to talk to the public about preventing fires and being prepared for them," Seelig said.

The new alert system will also have the effect of keeping cooperating county, state and federal agencies on their toes and ready to respond during times of higher risk, Seelig said.