Statewide Discussion: Fire danger continues today with the highest indices generally east of I-35 while rain/storms in the Panhandle and northwest Oklahoma provide a break from the building concern in those areas with increasing chances in western and northern Oklahoma this afternoon and evening. Tuesday will usher in dry air to western Oklahoma and areas that receive little or no rainfall today will experience elevated fire danger again. Further east on Tuesday, gulf moisture prompting higher dew point temperatures will provide a pause from recurrent afternoon relative humidity values dropping below 25% although no rainfall is currently in the mix. Overall, a slight reduction midweek with higher afternoon relative humidity values and no critical wind speeds to support rapid rates of fire spread despite temperatures warming into the +15° above normal range.
Today: The highest fire danger concern today will develop along and east of I-35 with progressively drier air moving further east to the OK/AR border. Rain and storms over the weekend in parts of the Oklahoma Panhandle continuing this morning into the northwestern counties will provide a short respite from fire danger concern in those locations. Rain/storm chances continue to build in far northwestern and western Oklahoma this afternoon extending into north-central Oklahoma this evening and overnight although decreasing as the system approaches the I-44 corridor. Relative humidity values will increase in advance of the rain potential although given composite fuel moisture lightning ignitions cannot be ruled out on the eastern edge storms.
- East of I-35: Clear skies, above normal temperatures 80°-85° and afternoon relative humidity values 23-28% will support 1-Hr. fuel moisture at 5% holding receptive fine-fuels in place. Given composite fuel moisture values reflected in Energy Release Component value +/- 95th percentile, resistance to control will continue on any going wildfire noting the large diameter fuels are completely combusting, problematic fire behavior is prevalent and resource commitment is above normal. South winds sustained 7-15 mph with some gusts topping 20 mph (especially north) will support moderate to rapid rates of fire spread in drought-stressed, grass-dominant fuels. Grasses where grazing has been absent will support head fire rates of spread 78-135 ft/min with flame lengths 9-15 ft. ROS nearer to 165 ft/min should be anticipated in the northern counties where heavier grass loading exists. In mixed fuels (Grass/brush/timber), ROS +/-50 ft/min and FL 7-9 ft. coupled with torching and spotting should be expected while timber litter will offer ROS +/-25 ft/min and FL around 5 ft.
- Western/Southwestern/Central Oklahoma: Rain-storm chances develop this afternoon into the evening posing lightning ignition potential associated with possible storms. Otherwise, relative humidity values will struggle to dip below 35% as temperatures warm into the 80°s holding fine-dad fuel moisture to around 7%. Atmospheric moisture increases into the late afternoon further limiting 1-hr. fuel moisture from dipping into critical concern. Any new wildfire will be subjected to southerly winds sustained 13-19 mph with erratic gusts in the vicinity of storm cells. Rangeland fuels will support head fire rates of spread 90-115 ft/min noting that fires occurring in the vicinity of storm cells will likely exhibit erratic fire behavior and bursts of ROS nearer to 175 ft/min.
Tuesday: Very good overnight moisture recovery will stall development of active burning conditions, and increased gulf moisture in the east will hold afternoon relative humidity values above 30% although dry conditions remain. In the wake of the passing storm system, dry air will penetrate western Oklahoma increasing fire danger for those areas where no rainfall is received although lower wind speeds will limit fire spread potential. Overall, a downtick in the number of fire is expected and probability of initial attack success is high.
Near-Term: Despite well-above normal temperatures, higher dewpoint temperatures will limit fine-dead fuel moisture from tapping critical values through mid-week and no anomalous wind speeds are forecasted. As such, rates of fire spread will support continued initial attack success. Next chance for rainfall may come late week as a cold front approaches the area, but forecaster confidence is low at this time.
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