This morning’s Fire Situation Report was focused on the Warnings and Watches and the fire danger in western Oklahoma as the weather develops. As a supplement to this morning’s report, we would like to offer some additional situation awareness.
Elevated fire danger is likely through the remainder of the week across western Oklahoma as well as increasing into central and then eastern regions of the state.
Fire danger will remain in western Oklahoma following the front and is likely to expand eastward as drier air develops. Temperatures will be cooler and winds will slacken, but fuel receptiveness will only increase.
The trend of above-normal temperatures and a couple of recent shots of moisture have prompted green-up in agricultural fields and to a limited extent in winter grasses. That will somewhat reduce fire behavior where the benefit is present, but timber fuels and the dominance of dormant grasses will continue to present potential for very active fire behavior in the foreseeable future.
Wednesday – The possibility of precipitation this evening in eastern Oklahoma may lessen fire danger in the area, if it happens. Drier air will push into central Oklahoma, drying fine fuels much more noticeably than the previous two days.
Western OK - Temperatures will be cooler with afternoon highs 50°-60° with minimal sky cover. Marginal overnight moisture recovery and declining dew point temperature will result in afternoon relative humidity values of 15-20%. Fine-dead fuel moisture will fall into the 4-5% range – very receptive. Northwest winds sustained 10-20 mph with some higher gusts will result in moderate to rapid rates of fire spread. Fires occurring on Tuesday will need to be closely monitored with emphasis on the eastern and southern portions especially where any large diameter fuels are present.
Central OK – Drier conditions will establish early in the burning period and widespread 20% RH observations are expected. Temperatures in the mid-50°’s to mid-60°’s and a good amount of sunshine will facilitate fuel fine fuel moisture in open and un-sheltered areas to reach the 5% mark. Timber litter fuels will lag behind that somewhat and offer an opportunity for a reduction in fire behavior, but will support increased fire behavior observed in days previous. Northwest winds 12-16 mph with gusts near 20 mph will promote rates of fire spread in grass dominated fuels as high as 250 ft./min. and 30 ft./min in timber fuels.
Eastern OK – Drier conditions are expected; however the significance of fire danger development will be largely dependent upon whether or not precipitation is realized this afternoon and overnight. Nonetheless, relative humidity values will fall below 30% tomorrow afternoon and some areas may observe as low as 20% prompting significant drying with northwest winds 10-15 mph. Large/significant fire occurrence is not expected, however increasing initial attack activity is expected into the afternoon.
Thursday – Dry conditions continue and winds will switch back to southwest through the day. Wind speeds are not expected to significant - 5-10 mph and limited gusts. Relative humidity values may likely be around 20% statewide in the afternoon. Receptive fuels will likely lend to increasing initial attack activity; however large/significant fire occurrence probability is not expected to be problematic.
Drew Daily, Fire Staff Forester, Oklahoma Forestry Services
Posted on Tue, February 28, 2017