Impacted counties include Lucas, Wood, Ottawa, Sandusky, Erie, Lorain, Hancock, Seneca, Huron, Medina, Wyandot, Crawford, Richland, Ashland, Wayne, Marion, Morrow, Holmes, and Know counties.
"Essentially a Red Flag Warning is issued when critical fire weather conditions are occurring or are imminent," Sarah Jamison said who is a Senior Service Hydrologist for the Cleveland at NWS. " A combination of winds, low relative humidity, and warm temperatures can contribute to extreme fire spread and fire behavior."
The reason you may have never heard of a Red Flag Warning is because Jamison said they are pretty rare.
The last one issued for our area was just about six years ago on June 28, 2012.
Another reason for the rarity is the criteria for Ohio needs to be just right:
Ten hour fuels must be at or below 8 percent. (A 10 hour fuel refers to dry items like grass, leaves, branches that would take 10 hours of climate moisture to no longer be a threat of quickly catching fire.)
The afternoon and evening relative humidity levels are expected to fall to 25 percent or lower and the surface winds (sustained or gusts) are expected to exceed 15 mph (13 knots) for at least two consecutive hours.
"Currently the ground liter (decayed leaves/ground debris) have dried out in recent days," Jamison said. "This with the low RH (relative humidity) and winds make the situation primed. We often don't meet the RH/Wind criteria in conjunction with the low fuel moisture as we do today, which is why this issuance is infrequent."
The storm prediction center issues Fire Weather Outlooks and currently Ohio is in the elevated level.
According to Jamison the Red Flag classification, "...are designed more for specific partners, i.e. forestry, fire services, ODNR, etc. than they are the general public."
That being said for the general public should stay away from outdoor burning at this time.